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Dual-500 king of the Castle
- Thread starter grapplesaw
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Lee,
Snagged the last one. (Only 1 I could find -- the law of Supply & Demand has conspired to make this a bit more dear...but given the lab I'm piecing together it's a relative bargain. (ie: It doesn't matter how much gear I've amassed, it's how many x how deep I have managed to test/fix/hotrod/WOPL/etc. (The old 'Price Per Use' metric to figure out the ROI - plus whatever I manage to learn from this adventure - that's priceless!)
And this book looks to be just the ticket to accelerate my "Zero-to-OK, I got this" time. :0)
Thanks again! When I said I wanted help spending my money, I meant it. And IMHO there's nothing like a small library of essential books at arm's length!
Stoked about this purchase!
Snagged the last one. (Only 1 I could find -- the law of Supply & Demand has conspired to make this a bit more dear...but given the lab I'm piecing together it's a relative bargain. (ie: It doesn't matter how much gear I've amassed, it's how many x how deep I have managed to test/fix/hotrod/WOPL/etc. (The old 'Price Per Use' metric to figure out the ROI - plus whatever I manage to learn from this adventure - that's priceless!)
And this book looks to be just the ticket to accelerate my "Zero-to-OK, I got this" time. :0)
Thanks again! When I said I wanted help spending my money, I meant it. And IMHO there's nothing like a small library of essential books at arm's length!
Stoked about this purchase!
Last edited:
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- Joined
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- Halfbiass...Electron Herder and Backass Woof
- Joined
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My last reply to this covered familiar ground having to do with the size & shape of the room vs. the physical wavelength of a given note.
But to better address your comment about room size vs. speaker size, (or more accurately, the speakers' ability to move a lot of air doesn't help make it sound better in a small room) I think I've got some additional insight to this phenomenon. My working theory is that when a system actually 'sounds loud' or 'congested' it's because we're not properly managing the energy that we are generating...and the higher the energy level, the more of a sonic mess all this becomes.
A better description would be that the energy we pumped into the room in the recent past is still decaying (that is, still audible) ...meanwhile, the right now energy is emanating from the loudspeakers on top of the old energy still bouncing back & forth in the 'smaller than optimal' room.
Before I continue, check out this short but very clear explanation of how they measure timing of the decay (reverberation) in a room.
As an example, let's say that you are listening to me talk outside, with no nearby reflecting surfaces, and therefore no reverberation. My voice is clear against a quiet background. Let's say that we then walk inside and enter a large empty IMAX theater (spacious + all the surfaces are also treated acoustically) and I start talking again. Still no problem, for the words that I am currently speaking are not having to compete with the words that I said .1 / .2 / .5+ seconds ago.
Finally we walk into a 12' x 20' concrete block single-car garage with bare walls, floor, low ceiling, the doors are closed, & there's nothing else in it. Now, even though I'm speaking to you at the same loudness & enunciation that I used in the first 2 scenarios, now you are having intermittent difficulty in making out the words I'm saying. (Especially if I'm wearing a mask & you can't lip read.)
The problem is intermittent based upon the timing - that is, if I spoke a word louder (for emphasis) in the recent past, but right this moment I'm speaking softly, then (depending upon the distance from reflecting surfaces) the louder reverberation of the word that you've already heard washes out the softer word that you have yet to hear enough to recognize. Ergo, no loss in the quantity of sound, yet actual communication between us suffers. (!)
Q: So why does this problem worsen with increasing sound pressure level?
A: Because as you can see in the graph, the decay time is a constant, whether it's a 40db whisper, or a 100db musical transient. The thing is, 40db is a soft sound, so it will take far less time to decay to inaudibility (25db?) vs the time it will take for that 100db transient to decay to the same level of inaudibility. (Which will vary from person to person, plus the additional variable of how much each person's hearing has level-shifted due to how much sound that they have been recently exposed to.)
****
Check this out -- musicians are aware of this phenomenon, but look at how they discuss/debate what it's like to drive a room into 'compression'.
No wonder room acoustics are so difficult to discuss - we don't even share the same vocabulary when describing the same phenomenon, and to be sure both musicians and gearheads like us both want the quality with the quantity. :0)
One more thing to ponder. Let's say that in a small room you are playing a set of small monitors with very dense cabinets. So dense & braced internally in fact that the only sound emanating from them is coming from the drivers themselves -- no acoustic radiation from the cabs!
Now the well-behaved monitors are removed and a much larger set of '70's-era loudspeakers are brought in. The cabs are large yet made of 1/4" plywood. Unbraced. And they are *not* ported, so when you get that 15" woofer going, it really puts the pressure to the cabinet. And when you hit the resonant frequency of the large side panel(s) they 'talk'. It's actually been proven that with certain loudspeakers that the *cabinets* will emit more acoustic energy at specific frequencies than the drivers themselves. And guess what? That cabinet resonance is from the music that immediately precedes the music emanating from the drivers at that same moment in time. (!)
At this point in time I was going to talk about being able to quantify loudspeaker cabinet energy storage issues using MLSSA, but this is already too long, so I'll just embed the link and leave that as an exercise for the reader.
****
Q: So, what does this all mean for you & I in our quest to have sound systems that just get bigger...instead of louder?
A: Most of us up 'til now only concern ourselves about how to best go about generating large quantities of clean, undistorted, acoustic power! But this is like building a car to accelerate very quickly to a high speed...but not worrying about if the brakes can haul it back down in an equally quick fashion.
So, in the land of audio, we have to make sure that whatever energy we create, we also give it a place to be attenuated/dissipated as quickly as possible. A quick example is that my speakers weigh 180 lbs each, but when I moved them into my house and they were sitting flat on the carpet, the bass was good at low listening levels, but with any real volume all the bass articulation/definition that helped me hear exactly which bassist I was listening to would disappear, and I would just hear a 'generic' bassist instead.
At first I thought it was a problem with the woofers, or maybe even my D500 amp running into trouble with the woofers...because I couldn't believe that 180-lb speakers would have an issue. As it turned out, I was talking to a fellow audio enthusiast at work, and he asked if I had tried the 'tiptoes'. "No, I didn't believe in them." So, of course he came down & together we put each speaker on 3 aluminum cones, flat edge on the bottom of the speaker, while the tip punched through the carpet & underlayment, and concentrated/coupled the entire weight of those speakers firmly into the 3/4" subfloor. Now, when the woofers really started working, the whole action/reaction thing now involved the solid subfloor in a 24'x24' room. (!)
Voila! The bass energy that was in the cabinet previously had nowhere to go, and so these large speakers were physically 'trembling' when sitting atop the carpet, smearing stuff up, but only when I turned it up towards 'life-sized' listening levels. Now, with the tiptoes installed, the speakers were able to 'sink' (ground) the old energy into the subfloor, and you could feel that the cabinets were much more stationary. And most importantly, the quality of the bass remained the same as I turned up the volume...
And the way that you make an entire room 'act' larger than it is, acoustically? That's where the bass traps in the corners, and acoustic treatments on the walls come into play. Because, if you do it right, it will help to mitigate the generation of standing waves in your listening room.
Apologies to anyone still wading through this, but if you are picking up what I'm putting down, then you may well find yourself listening to every room you enter for the next while. It's really interesting to do so. And finally, if you leave this post with more questions than you did when you entered, *perfect*. Because, the more I learn, the less I know. And I'm hoping that all this will spark some quality conversation...eventually leading to increased shared knowledge about this rather esoteric audio/acoustic theory.
"That's all I've got to say about that." - 3D gump
But to better address your comment about room size vs. speaker size, (or more accurately, the speakers' ability to move a lot of air doesn't help make it sound better in a small room) I think I've got some additional insight to this phenomenon. My working theory is that when a system actually 'sounds loud' or 'congested' it's because we're not properly managing the energy that we are generating...and the higher the energy level, the more of a sonic mess all this becomes.
A better description would be that the energy we pumped into the room in the recent past is still decaying (that is, still audible) ...meanwhile, the right now energy is emanating from the loudspeakers on top of the old energy still bouncing back & forth in the 'smaller than optimal' room.
Before I continue, check out this short but very clear explanation of how they measure timing of the decay (reverberation) in a room.
As an example, let's say that you are listening to me talk outside, with no nearby reflecting surfaces, and therefore no reverberation. My voice is clear against a quiet background. Let's say that we then walk inside and enter a large empty IMAX theater (spacious + all the surfaces are also treated acoustically) and I start talking again. Still no problem, for the words that I am currently speaking are not having to compete with the words that I said .1 / .2 / .5+ seconds ago.
Finally we walk into a 12' x 20' concrete block single-car garage with bare walls, floor, low ceiling, the doors are closed, & there's nothing else in it. Now, even though I'm speaking to you at the same loudness & enunciation that I used in the first 2 scenarios, now you are having intermittent difficulty in making out the words I'm saying. (Especially if I'm wearing a mask & you can't lip read.)
The problem is intermittent based upon the timing - that is, if I spoke a word louder (for emphasis) in the recent past, but right this moment I'm speaking softly, then (depending upon the distance from reflecting surfaces) the louder reverberation of the word that you've already heard washes out the softer word that you have yet to hear enough to recognize. Ergo, no loss in the quantity of sound, yet actual communication between us suffers. (!)
Q: So why does this problem worsen with increasing sound pressure level?
A: Because as you can see in the graph, the decay time is a constant, whether it's a 40db whisper, or a 100db musical transient. The thing is, 40db is a soft sound, so it will take far less time to decay to inaudibility (25db?) vs the time it will take for that 100db transient to decay to the same level of inaudibility. (Which will vary from person to person, plus the additional variable of how much each person's hearing has level-shifted due to how much sound that they have been recently exposed to.)
****
Check this out -- musicians are aware of this phenomenon, but look at how they discuss/debate what it's like to drive a room into 'compression'.
No wonder room acoustics are so difficult to discuss - we don't even share the same vocabulary when describing the same phenomenon, and to be sure both musicians and gearheads like us both want the quality with the quantity. :0)
One more thing to ponder. Let's say that in a small room you are playing a set of small monitors with very dense cabinets. So dense & braced internally in fact that the only sound emanating from them is coming from the drivers themselves -- no acoustic radiation from the cabs!
Now the well-behaved monitors are removed and a much larger set of '70's-era loudspeakers are brought in. The cabs are large yet made of 1/4" plywood. Unbraced. And they are *not* ported, so when you get that 15" woofer going, it really puts the pressure to the cabinet. And when you hit the resonant frequency of the large side panel(s) they 'talk'. It's actually been proven that with certain loudspeakers that the *cabinets* will emit more acoustic energy at specific frequencies than the drivers themselves. And guess what? That cabinet resonance is from the music that immediately precedes the music emanating from the drivers at that same moment in time. (!)
At this point in time I was going to talk about being able to quantify loudspeaker cabinet energy storage issues using MLSSA, but this is already too long, so I'll just embed the link and leave that as an exercise for the reader.
****
Q: So, what does this all mean for you & I in our quest to have sound systems that just get bigger...instead of louder?
A: Most of us up 'til now only concern ourselves about how to best go about generating large quantities of clean, undistorted, acoustic power! But this is like building a car to accelerate very quickly to a high speed...but not worrying about if the brakes can haul it back down in an equally quick fashion.
So, in the land of audio, we have to make sure that whatever energy we create, we also give it a place to be attenuated/dissipated as quickly as possible. A quick example is that my speakers weigh 180 lbs each, but when I moved them into my house and they were sitting flat on the carpet, the bass was good at low listening levels, but with any real volume all the bass articulation/definition that helped me hear exactly which bassist I was listening to would disappear, and I would just hear a 'generic' bassist instead.
At first I thought it was a problem with the woofers, or maybe even my D500 amp running into trouble with the woofers...because I couldn't believe that 180-lb speakers would have an issue. As it turned out, I was talking to a fellow audio enthusiast at work, and he asked if I had tried the 'tiptoes'. "No, I didn't believe in them." So, of course he came down & together we put each speaker on 3 aluminum cones, flat edge on the bottom of the speaker, while the tip punched through the carpet & underlayment, and concentrated/coupled the entire weight of those speakers firmly into the 3/4" subfloor. Now, when the woofers really started working, the whole action/reaction thing now involved the solid subfloor in a 24'x24' room. (!)
Voila! The bass energy that was in the cabinet previously had nowhere to go, and so these large speakers were physically 'trembling' when sitting atop the carpet, smearing stuff up, but only when I turned it up towards 'life-sized' listening levels. Now, with the tiptoes installed, the speakers were able to 'sink' (ground) the old energy into the subfloor, and you could feel that the cabinets were much more stationary. And most importantly, the quality of the bass remained the same as I turned up the volume...
And the way that you make an entire room 'act' larger than it is, acoustically? That's where the bass traps in the corners, and acoustic treatments on the walls come into play. Because, if you do it right, it will help to mitigate the generation of standing waves in your listening room.
Apologies to anyone still wading through this, but if you are picking up what I'm putting down, then you may well find yourself listening to every room you enter for the next while. It's really interesting to do so. And finally, if you leave this post with more questions than you did when you entered, *perfect*. Because, the more I learn, the less I know. And I'm hoping that all this will spark some quality conversation...eventually leading to increased shared knowledge about this rather esoteric audio/acoustic theory.
"That's all I've got to say about that." - 3D gump
Last edited:
3D, spot on.
I have experienced the same phenomena with speaker spikes but will say that the level of effectiveness depends on the subfloor and flooring. For example any carpeted room, spikes are a must. In rooms with suspended wood subfloors (second stories or peer and beam) using isolation plinths between the speakers and floors to reduce floor vibration is very affective. My current floors are 1/2 inch engineered solid wood, glued directly to the concrete subfloor, spikes have very little affect, in fact, I replaced my spikes with very dense felt pucks and could not tell the difference. My motivation for getting rid of the spikes was to be able to move the speakers without accidentally scratching the floors. Originally I had the type of spikes that have mating disks under the tips and are designed for hardwood floors but if while sliding them, one of the disks stuck to the floor a disaster could follow.
As to bass traps, yep they can be be extremely effective and anyone considering adding them should check out the many DIY videos out there, for very little money and time you can build and experiment with them.
On either side of my main system are two doorways, each opening into 12x10 rooms that turns out are the best bass traps you can have. The difference between having those doors closed versus open is amazing, closing the doors causes a spike at around 40hz, doors open, the room is pretty flat down to 25hz, then starts to roll off.
If I ever build a dedicated listening room, it will have a false wall with openings in each corner leading behind it into a space that is at least 5 feet deep and runs the width of the room. This is for two reasons, first the bass trap affect and secondly to be able to build audio racks into the wall so that my equipment is flush on the listening side and I have easy access the the cabling on the back side. A third advantage is that it naturally places the speakers out into the listening room without having anything between them. Ahh someday….
I have experienced the same phenomena with speaker spikes but will say that the level of effectiveness depends on the subfloor and flooring. For example any carpeted room, spikes are a must. In rooms with suspended wood subfloors (second stories or peer and beam) using isolation plinths between the speakers and floors to reduce floor vibration is very affective. My current floors are 1/2 inch engineered solid wood, glued directly to the concrete subfloor, spikes have very little affect, in fact, I replaced my spikes with very dense felt pucks and could not tell the difference. My motivation for getting rid of the spikes was to be able to move the speakers without accidentally scratching the floors. Originally I had the type of spikes that have mating disks under the tips and are designed for hardwood floors but if while sliding them, one of the disks stuck to the floor a disaster could follow.
As to bass traps, yep they can be be extremely effective and anyone considering adding them should check out the many DIY videos out there, for very little money and time you can build and experiment with them.
On either side of my main system are two doorways, each opening into 12x10 rooms that turns out are the best bass traps you can have. The difference between having those doors closed versus open is amazing, closing the doors causes a spike at around 40hz, doors open, the room is pretty flat down to 25hz, then starts to roll off.
If I ever build a dedicated listening room, it will have a false wall with openings in each corner leading behind it into a space that is at least 5 feet deep and runs the width of the room. This is for two reasons, first the bass trap affect and secondly to be able to build audio racks into the wall so that my equipment is flush on the listening side and I have easy access the the cabling on the back side. A third advantage is that it naturally places the speakers out into the listening room without having anything between them. Ahh someday….
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Before continuing the discussion on how our listening rooms interact (either aiding or detracting) with our equipment -- I just wanted to stop & attempt to establish some relevance with grapplesaw's D-500 build thread. Instead of another 1,000 words, I thought I'd post the following pic that summarizes the best room I've had my system in to date...and how fortunate I was to have heard my system in it before I had to relocate from VT to southern NH:
The bottom line is that after I WOPL my twin D500s the new limiting factor of the listening experience will no doubt be the room that the system is in. And that I need to keep this in mind. (Hint: A goal without a plan is just a wish! :0)
More to follow -
The bottom line is that after I WOPL my twin D500s the new limiting factor of the listening experience will no doubt be the room that the system is in. And that I need to keep this in mind. (Hint: A goal without a plan is just a wish! :0)
More to follow -
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In case my hand drawn graph isn't intuitive, essentially the 24' x 24' room I first had my D500 driving my QLS-1s was better than I realized at the time. I lived in Bristol, VT, a quiet village with a block-long main street & a single intersection with a traffic light. The house was ~2 years old when I moved in, the walls were 2"x6" construction, (for extra insulation) the attic had R-38 insulation, I insulated the floor to R-25, double-pane glass, etc. The house sat above the village, supposedly was sited where the old rope tow used to be. It was the quietest house I had ever lived in, before or since. A couple of local brothers had built it, and their workmanship was evident. There wasn't a creak in the house - it was like living in a hushed library.
As a member of Field Service Training I had volunteered to relocate from central MA to VT in order to teach a new VAX computer being built at the Burlington mfg. plant. (The corporate training center didn't have enough power & A/C to handle the new machines, so instead we had a small cadre of approx. a dozen people all relocate to VT in order to provide worldwide training right where the machines were being built.
It was perfect - some of the very best training I've ever delivered. Lasted ~4 years. And when this machine went out of production, my plan was to stay in VT, join the manufacturing group, and, if necessary mow the lawn if need be, for I loved living there, quality of life, etc. But as the company started to contract, mother DEC shuttered the plant. So I ended up taking a corporate support function, working in an engineering group in southern NH.
And that's how I ended up moving all my kit into an approx. 14' x 24' front-to-back living room in a small saltbox in southern NH. The house was on a circle (cul de sac) at the far edge of town, quiet street, and most importantly, when my daughters got older they would be going to Pinkerton Academy, a private high school that all the public school kids went to. (That part worked flawlessly, whew. :0)
...but I digress. This house was ~7 years old when I bought it, which to me meant that it was still 'new'. But it was built in '86, and although everything was built to code, it was built during a local boom, and must have been built in a hurry. Except for the ceramic tile in the kitchen & linoleum in the bathrooms, the entire house was carpeted...but the floors creaked with every step. (!) It sounded like a house that was 10x older than it was.
However, I wasn't focused on that. First things first, get the main system up & running asap! Figuring that the new room being 1/2 the size of the old one would only make for a mo' better listening excitement, I was stunned by how 'loud & boomy' it sounded. Instead of being able to follow any instrument/musician I wanted, it just sounded like a giant boombox with no imaging & one note bass. I couldn't believe it was the same equipment I had been listening to a couple of weeks prior a couple of hundred miles north of where I was stuck now...
As a member of Field Service Training I had volunteered to relocate from central MA to VT in order to teach a new VAX computer being built at the Burlington mfg. plant. (The corporate training center didn't have enough power & A/C to handle the new machines, so instead we had a small cadre of approx. a dozen people all relocate to VT in order to provide worldwide training right where the machines were being built.
It was perfect - some of the very best training I've ever delivered. Lasted ~4 years. And when this machine went out of production, my plan was to stay in VT, join the manufacturing group, and, if necessary mow the lawn if need be, for I loved living there, quality of life, etc. But as the company started to contract, mother DEC shuttered the plant. So I ended up taking a corporate support function, working in an engineering group in southern NH.
And that's how I ended up moving all my kit into an approx. 14' x 24' front-to-back living room in a small saltbox in southern NH. The house was on a circle (cul de sac) at the far edge of town, quiet street, and most importantly, when my daughters got older they would be going to Pinkerton Academy, a private high school that all the public school kids went to. (That part worked flawlessly, whew. :0)
...but I digress. This house was ~7 years old when I bought it, which to me meant that it was still 'new'. But it was built in '86, and although everything was built to code, it was built during a local boom, and must have been built in a hurry. Except for the ceramic tile in the kitchen & linoleum in the bathrooms, the entire house was carpeted...but the floors creaked with every step. (!) It sounded like a house that was 10x older than it was.
However, I wasn't focused on that. First things first, get the main system up & running asap! Figuring that the new room being 1/2 the size of the old one would only make for a mo' better listening excitement, I was stunned by how 'loud & boomy' it sounded. Instead of being able to follow any instrument/musician I wanted, it just sounded like a giant boombox with no imaging & one note bass. I couldn't believe it was the same equipment I had been listening to a couple of weeks prior a couple of hundred miles north of where I was stuck now...
Last edited:
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NeverSatisfied, from scratch I had to learn for myself what you just stated so succintly. (!)
You know, if you played music from a smaller source in the problem room it wasn't too bad. If I had been a Bang & Olufsen devotee I probably would have moved in, enjoyed some classical / blues / jazz at rational levels, and none of this hoopla would ever be written.
Furthermore, if I had initially bought those used QLS-1s & had brought them directly to *this* house, from what I heard I would have come to the conclusion that nostalgia** is not part of a good main listening system, & I would have 'fixed' this error by selling them & found something else...
****
But the fact of the matter is that the system sounded so different (and I had no idea why) simply meant that my unfamiliarity with acoustic theory was doing me no favors. I decided early on that instead of just 'buying my way out of this', I was going to learn as much as possible, get the system to work as close as I could as it used to sound...and only 'trade up' if that was the only real solution. (Besides, I could fall back on the ESS AMT-1b's, for I still had those.)
One of my mantras was "There is nothing more expensive than a lack of knowledge." So off to the library (a pre-internet thing :0) and start wading through relevant textbooks...
First things first. The mids & highs were alright (but the imaging was off) ...but the bass was bad, no matter what the level. Flabby bass, no impact, droning, drew attention to itself in a bad way, obscured the music -- sounded like when you hear too-much subwoofer doing one thing while the system it was added to was doing something else. (!) I'm serious, if I didn't know any better I would have decided that Mr. Nudell had a rare off day when these were his signature speakers back in the mid-70s.
Of course the acoustic textbooks were all pure theory, and focused exclusively on frequency vs. wavelength, interference patterns, blah blah blah. But I was driving the room from the back wall, and the speakers were playing into a narrower room, but at the same time both rooms had been the same depth (24') from the loudspeaker perspective? How could the bass be so different?
****
As it turns out, there were not one but two overlapping problems. The first solution came to me one day while the floors were creaking with every single step I took. And I thought back to when I added the tiptoes to the system up in VT, and it cured the 'generic' bassist thing at higher volumes.
Sure, I had the same tiptoes under the speakers through the carpet & into the subfloor...but what good would that do IF the subfloor itself was sloppy loose? The solution was going to solve at least one problem -- upgrading from 7-year-old carpet of questionable color choice to a nice, new 3/4" tongue-and-groove red oak hardwood floor. (NOTE: Installing a hardwood floor like this was a DIY bucket list item for yours truly. :0)
If I was right, the new hardwood floor would also help improve the main system's bass *quality*.
****
So when I pulled up the carpet, I was amazed to find that each sheet of 4' x 8' x 3/4" subfloor was loose/floating, because it had been nailed down, and the nails had all loosened over 7 years of cycling between shrinking & expanding. (No doubt from low humidity in winter to higher humidity in summer. NOTE: No central air, just windows & fans.)
The fix? A generous serving of deck screws. The sub-floor pulled down so much that all the old nails were proud, so they were easily removed with a crowbar. Then the felt paper. With the floor stabilized, down went the 3/4" T&G red oak hardwood floor. And I finished it with a couple of coats of polyurethane. After it was all said and done, you could now walk through the 1st floor with nary a creak, pop, or groan.
And thanks to modern technology, today I was able to pull this picture from Zillow that some real estate agent recently took of this very room. The picture quality is so-so, but at least you can see the (partial) sonic solution that I installed ~27 years ago:
** Nostalgia: Back in the mid-70s I had seen/heard a set of then brand-spanking new QLS-1s in a boutique audio joint in/near the Kansas City Plaza. 2 memories stand out to this day -- the first was that these speakers by themselves cost 2.5 times what my used car cost, and the second was that the store owner kept glancing at my grass-stained Adidas & had mentally written me off completely as a potential customer. To tell you the truth, when I left the store that day I never thought that I would ever actually buy a pair of them ~15 years later...
:0)
You know, if you played music from a smaller source in the problem room it wasn't too bad. If I had been a Bang & Olufsen devotee I probably would have moved in, enjoyed some classical / blues / jazz at rational levels, and none of this hoopla would ever be written.
Furthermore, if I had initially bought those used QLS-1s & had brought them directly to *this* house, from what I heard I would have come to the conclusion that nostalgia** is not part of a good main listening system, & I would have 'fixed' this error by selling them & found something else...
****
But the fact of the matter is that the system sounded so different (and I had no idea why) simply meant that my unfamiliarity with acoustic theory was doing me no favors. I decided early on that instead of just 'buying my way out of this', I was going to learn as much as possible, get the system to work as close as I could as it used to sound...and only 'trade up' if that was the only real solution. (Besides, I could fall back on the ESS AMT-1b's, for I still had those.)
One of my mantras was "There is nothing more expensive than a lack of knowledge." So off to the library (a pre-internet thing :0) and start wading through relevant textbooks...
First things first. The mids & highs were alright (but the imaging was off) ...but the bass was bad, no matter what the level. Flabby bass, no impact, droning, drew attention to itself in a bad way, obscured the music -- sounded like when you hear too-much subwoofer doing one thing while the system it was added to was doing something else. (!) I'm serious, if I didn't know any better I would have decided that Mr. Nudell had a rare off day when these were his signature speakers back in the mid-70s.
Of course the acoustic textbooks were all pure theory, and focused exclusively on frequency vs. wavelength, interference patterns, blah blah blah. But I was driving the room from the back wall, and the speakers were playing into a narrower room, but at the same time both rooms had been the same depth (24') from the loudspeaker perspective? How could the bass be so different?
****
As it turns out, there were not one but two overlapping problems. The first solution came to me one day while the floors were creaking with every single step I took. And I thought back to when I added the tiptoes to the system up in VT, and it cured the 'generic' bassist thing at higher volumes.
Sure, I had the same tiptoes under the speakers through the carpet & into the subfloor...but what good would that do IF the subfloor itself was sloppy loose? The solution was going to solve at least one problem -- upgrading from 7-year-old carpet of questionable color choice to a nice, new 3/4" tongue-and-groove red oak hardwood floor. (NOTE: Installing a hardwood floor like this was a DIY bucket list item for yours truly. :0)
If I was right, the new hardwood floor would also help improve the main system's bass *quality*.
****
So when I pulled up the carpet, I was amazed to find that each sheet of 4' x 8' x 3/4" subfloor was loose/floating, because it had been nailed down, and the nails had all loosened over 7 years of cycling between shrinking & expanding. (No doubt from low humidity in winter to higher humidity in summer. NOTE: No central air, just windows & fans.)
The fix? A generous serving of deck screws. The sub-floor pulled down so much that all the old nails were proud, so they were easily removed with a crowbar. Then the felt paper. With the floor stabilized, down went the 3/4" T&G red oak hardwood floor. And I finished it with a couple of coats of polyurethane. After it was all said and done, you could now walk through the 1st floor with nary a creak, pop, or groan.
And thanks to modern technology, today I was able to pull this picture from Zillow that some real estate agent recently took of this very room. The picture quality is so-so, but at least you can see the (partial) sonic solution that I installed ~27 years ago:
** Nostalgia: Back in the mid-70s I had seen/heard a set of then brand-spanking new QLS-1s in a boutique audio joint in/near the Kansas City Plaza. 2 memories stand out to this day -- the first was that these speakers by themselves cost 2.5 times what my used car cost, and the second was that the store owner kept glancing at my grass-stained Adidas & had mentally written me off completely as a potential customer. To tell you the truth, when I left the store that day I never thought that I would ever actually buy a pair of them ~15 years later...
:0)
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- Joined
- Nov 15, 2021
- Messages
- 482
- Location
- near Liverpool, NY
- Tagline
- Lifelong student / listening = bliss
After reinstalling the sound system onto the new flooring (Note: The tiptoes** were flipped, flat surface now to the new floor, spikes into the MDF bottoms of the speakers) the low-level bass was much better than before - what a relief. But turning up the system the transients were still bad...but now it wasn't just the bass, it was *all* of the music. It now sounded like a factory car radio where the vocals (& everything else) go bad in time to the bass beat. (Indicating the power supply is caving in & affecting everything.)
Given this, I scoped the AC out of the wall as I played the music. I still remember slowing down the trace & watching the 60Hz voltage envelope sag from ~120v to ~95 volts! (Of course, both + and - edges of the envelope caved towards the center of the display in perfect time with the bass notes?
I had another clue, in that playing the system loudly did not make the lights flicker anywhere else in the house?
Going back to the circuit breaker panel, I found the circuit breaker feeding the sound system, and didn't see any real drop in voltage on either 120v leg from the street? WTF? It was as if I had a marginal current path between the circuit breaker panel & the wall outlet?
Further troubleshooting uncovered that this one 15A circuit breaker fed either 3 or 4 outlets -- they were all daisy-chained to each other, and of course the outlet on the back wall of the living room was the last outlet in the daisy chain. Guess what? In their haste to throw this house together, not a single slotted screwdriver was harmed in connecting these outlets to the house wiring -- they were ALL back-wired, relying on the (small-surface-area) spring-loaded connectors in the rear of the cheap residential-grade outlets!
My solution? I added a dedicated 120v, 20-amp circuit, with an unbroken 12-gauge run of Romex between the new 20a circuit breaker in the panel to a new commercial-grade outlet on the next stud over on the back wall of the living room.
And yes, this time I connected the wires firmly to the outlet using the old-school screws on the side. (!)
****
So, after all that, the good news is that not only did the voltage in the new dedicated 20A circuit now only sag only 2-3 volts total at full tilt, but now my main music system sounded like it did back in VT!
The moral of the story? For lack of a better technical description, a lot of the 'magic' that a Phase Linear amp brings to the table is it's ability to effortlessly deliver the beat, the swing, the swagger, the pulse, the crescendo, the whatever-you-want-to-call-it that makes listening to music SO different than listening to a steady test tone.
That is, unless you starve it for current when it needs it the most.
And, you compound the problem by installing it ever so carefully on top of a loose subfloor.
Q: So, am I upset that the clowns that threw that house together in southern NH caused me so much time & effort troubleshooting?
A: No. Because as I've said before, "Experience is the knowledge that you've gained AFTER you needed it."
Oh yeah, almost forgot. Now when I played the system enthusiastically in the living room, the lights in the kitchen now dimmed ever so slightly...so the new circuit was pulling nice & hard against the circuit breaker panel. FWIW I'm glad that I remeasured the AC power with the new circuit installed, because I now know the difference in how the system sounds when a (nominally) 120v circuit gets pulled down to 117v...versus the way it sounds when a 120v circuit gets pulled down to ~95 volts at the outlet. (!)
So, if you went to the trouble to find yourself a big amp to entertain yourself with sonically (especially a Class B amp, where the current draw from the wall outlet is not a constant like it is with a Class A amp, but the current draw is a 'Pay as you go' with the music type deal) ...then when it comes to your AC feed to your system, you should follow the sage advice of President Reagan: "Trust, but Verify." The good news is that instead of FUD (Fear, Uncertainty, & Doubt) you can easily (& quietly) load test a 120v outlet with nothing more than a voltmeter & a righteous blow dryer.
That's all I've got to say about that. -- 3D gump
**Speaker Tiptoes must be a niche product. I found exactly one picture on the internet showing a set of Tiptoes similar to the ones I used. (Facing down into carpet; flipped & facing up when used on a hardwood floor. (See attached photo at bottom of this post.)
Given this, I scoped the AC out of the wall as I played the music. I still remember slowing down the trace & watching the 60Hz voltage envelope sag from ~120v to ~95 volts! (Of course, both + and - edges of the envelope caved towards the center of the display in perfect time with the bass notes?
I had another clue, in that playing the system loudly did not make the lights flicker anywhere else in the house?
Going back to the circuit breaker panel, I found the circuit breaker feeding the sound system, and didn't see any real drop in voltage on either 120v leg from the street? WTF? It was as if I had a marginal current path between the circuit breaker panel & the wall outlet?
Further troubleshooting uncovered that this one 15A circuit breaker fed either 3 or 4 outlets -- they were all daisy-chained to each other, and of course the outlet on the back wall of the living room was the last outlet in the daisy chain. Guess what? In their haste to throw this house together, not a single slotted screwdriver was harmed in connecting these outlets to the house wiring -- they were ALL back-wired, relying on the (small-surface-area) spring-loaded connectors in the rear of the cheap residential-grade outlets!
My solution? I added a dedicated 120v, 20-amp circuit, with an unbroken 12-gauge run of Romex between the new 20a circuit breaker in the panel to a new commercial-grade outlet on the next stud over on the back wall of the living room.
And yes, this time I connected the wires firmly to the outlet using the old-school screws on the side. (!)
****
So, after all that, the good news is that not only did the voltage in the new dedicated 20A circuit now only sag only 2-3 volts total at full tilt, but now my main music system sounded like it did back in VT!
The moral of the story? For lack of a better technical description, a lot of the 'magic' that a Phase Linear amp brings to the table is it's ability to effortlessly deliver the beat, the swing, the swagger, the pulse, the crescendo, the whatever-you-want-to-call-it that makes listening to music SO different than listening to a steady test tone.
That is, unless you starve it for current when it needs it the most.
And, you compound the problem by installing it ever so carefully on top of a loose subfloor.
Q: So, am I upset that the clowns that threw that house together in southern NH caused me so much time & effort troubleshooting?
A: No. Because as I've said before, "Experience is the knowledge that you've gained AFTER you needed it."
Oh yeah, almost forgot. Now when I played the system enthusiastically in the living room, the lights in the kitchen now dimmed ever so slightly...so the new circuit was pulling nice & hard against the circuit breaker panel. FWIW I'm glad that I remeasured the AC power with the new circuit installed, because I now know the difference in how the system sounds when a (nominally) 120v circuit gets pulled down to 117v...versus the way it sounds when a 120v circuit gets pulled down to ~95 volts at the outlet. (!)
So, if you went to the trouble to find yourself a big amp to entertain yourself with sonically (especially a Class B amp, where the current draw from the wall outlet is not a constant like it is with a Class A amp, but the current draw is a 'Pay as you go' with the music type deal) ...then when it comes to your AC feed to your system, you should follow the sage advice of President Reagan: "Trust, but Verify." The good news is that instead of FUD (Fear, Uncertainty, & Doubt) you can easily (& quietly) load test a 120v outlet with nothing more than a voltmeter & a righteous blow dryer.
That's all I've got to say about that. -- 3D gump
**Speaker Tiptoes must be a niche product. I found exactly one picture on the internet showing a set of Tiptoes similar to the ones I used. (Facing down into carpet; flipped & facing up when used on a hardwood floor. (See attached photo at bottom of this post.)
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- Joined
- Nov 15, 2021
- Messages
- 482
- Location
- near Liverpool, NY
- Tagline
- Lifelong student / listening = bliss
Guess what? I was feeling so bad for dragging the reader(s) through my personal power saga from the mid 1990s, I had the idea to test a couple of outlets picked at random *this evening* just to show you what you can find in a 'newish' (11 year old) place I am currently leasing.
My test equipment? 1) An 1875-watt Conair hair dryer, and 2) My RCA Line Meter. I compared 2 different outlets in the kitchen, picked at random, and tested each one, voltage with no load, followed immediately by a voltage check at "1875 watts".
Good outlet, no load:
118v AC indicated
Good outlet, 1875 watt load:
116v AC indicated
Suspect outlet, no load:
117.5v AC indicated
Suspect outlet, 1875 watt load:
113v AC indicated
****
So there you have it. Using the same meter & blow dryer, the only variable are the outlets themselves, and they are installed within 10' of each other in the same kitchen.
The good outlet only dropped 2 volts when loaded, whereas the suspect outlet dropped over twice as much!
NOTE1: For what it's worth, no lights dimmed anywhere in the abode during this testing...
NOTE2: As a point of reference, I just looked at one of the D500s, and the sticker says that it pulls a maximum of "1500 watts". NOTE: This must be a steady-state at rated power, because I know they can pull pretty hard during a big transient.
****
The above is simply food for thought. If I was the owner of this joint (instead of just leasing) I would spend the ~$3 for a commercial grade outlet, swap out the suspect one, and retest. I do know that the suspect outlet is in heavy rotation, whereas the other one is never used...and it also has a firmer mechanical grip on the plug when it is time to insert or remove.
Cheers --
My test equipment? 1) An 1875-watt Conair hair dryer, and 2) My RCA Line Meter. I compared 2 different outlets in the kitchen, picked at random, and tested each one, voltage with no load, followed immediately by a voltage check at "1875 watts".
Good outlet, no load:
118v AC indicated
Good outlet, 1875 watt load:
116v AC indicated
Suspect outlet, no load:
117.5v AC indicated
Suspect outlet, 1875 watt load:
113v AC indicated
****
So there you have it. Using the same meter & blow dryer, the only variable are the outlets themselves, and they are installed within 10' of each other in the same kitchen.
The good outlet only dropped 2 volts when loaded, whereas the suspect outlet dropped over twice as much!
NOTE1: For what it's worth, no lights dimmed anywhere in the abode during this testing...
NOTE2: As a point of reference, I just looked at one of the D500s, and the sticker says that it pulls a maximum of "1500 watts". NOTE: This must be a steady-state at rated power, because I know they can pull pretty hard during a big transient.
****
The above is simply food for thought. If I was the owner of this joint (instead of just leasing) I would spend the ~$3 for a commercial grade outlet, swap out the suspect one, and retest. I do know that the suspect outlet is in heavy rotation, whereas the other one is never used...and it also has a firmer mechanical grip on the plug when it is time to insert or remove.
Cheers --
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