A Question That Has Burned In My Mind For Years...

[pennysdad]

This looks like an opportunity for me to ask some questions...

I want a subwoofer! I like my ADS 1290 speakers, except one thing: they’re a bit thin on the bass. I can drive them harder with an EQ, but then I hit a limit to the cone excursions.

I’ve been looking at a Klipsch (recommend another, if you want..) sub. I see that they have connections from the amp and then to the speakers. This is an active xo, correct? Or should I connect the pre out to an active xo and feed two separate outputs (now that I have two amps). For the second option, I want to keep the higher bass directed to the 1290s, and the extreme bottom to the sub- I suppose these xos are tunable?

I have no experience with these, as I’ve said before, I’m curious to hear your thoughts. Thanks!

Look for a JBL 2235 15" speaker. They can go to 17Hz in a properly tuned box. It's what I use. Now the funny thing is, most wouldn't know the difference between 45Hz and 20Hz let alone 17Hz. In reality, you can't really appreciably hear below 20Hz regardless of those that would argue they can. Although you can't 'hear' it, you can 'feel' it, and lower. That's where the 'magic' lies. But 45Hz is a 'happy' frequency. It's where most bass is appreciated and can be heard easily, and usually it's enough. Although once you've experienced lower registers it's hard to accept anything else.
I have this Chinese 10" baby sub, and it's tuned to 35Hz, and damn it sounds great. Go figure. I guess because it suits lots of stuff that's recorded these days, but my big JBL B380 with the 2235 really kills it, but until you turn the JBL on, the 10" is usually more than adequate.
... and yes, active x-o's are generally always tuneable. Try and find an old DBX Driverack [PA or 260]. Fairly straightforward bit of kit and can do heaps and has great specs. https://www.manualslib.com/manual/452242/Dbx-Driverack-Pa.html

 

[pennysdad]

This looks like an opportunity for me to ask some questions...

Or should I connect the pre out to an active xo and feed two separate outputs (now that I have two amps).

For the second option, I want to keep the higher bass directed to the 1290s, and the extreme bottom to the sub- I suppose these xos are tunable?

Yes to part one and yes [also] to part two.

 

[FredR]

This looks like an opportunity for me to ask some questions...

I want a subwoofer! I like my ADS 1290 speakers, except one thing: they’re a bit thin on the bass. I can drive them harder with an EQ, but then I hit a limit to the cone excursions.

I’ve been looking at a Klipsch (recommend another, if you want..) sub. I see that they have connections from the amp and then to the speakers. This is an active xo, correct? Or should I connect the pre out to an active xo and feed two separate outputs (now that I have two amps). For the second option, I want to keep the higher bass directed to the 1290s, and the extreme bottom to the sub- I suppose these xos are tunable?

I have no experience with these, as I’ve said before, I’m curious to hear your thoughts. Thanks!

I built one of these a few years ago. They sell the box for it to go in as well. Definitely like it. Will vibrate the nails out of drywall. Make sure your home uses screws.

https://www.parts-express.com/Dayton-Audio-UM18-22-18-Ultimax-DVC-Subwoofer-2-ohms-Per-Co-295-518

Drive it with one of these.

https://hometheaterhifi.com/reviews...xpa-1-gen-2-monoblock-power-amplifier-review/

 

[George S.]

This looks like an opportunity for me to ask some questions...

I want a subwoofer! I like my ADS 1290 speakers, except one thing: they’re a bit thin on the bass. I can drive them harder with an EQ, but then I hit a limit to the cone excursions.

I’ve been looking at a Klipsch (recommend another, if you want..) sub. I see that they have connections from the amp and then to the speakers. This is an active xo, correct? Or should I connect the pre out to an active xo and feed two separate outputs (now that I have two amps). For the second option, I want to keep the higher bass directed to the 1290s, and the extreme bottom to the sub- I suppose these xos are tunable?

I have no experience with these, as I’ve said before, I’m curious to hear your thoughts. Thanks!

I have 1 completely WOPL'd 400 S2 with Joe's meters calibrated to 40 Vrms driving two Parts Express/Dayton Audio 15" Ultimax subs in the standard knockdown box they sell for it. I agree, the real magic occurs with the frequencies you can't hear but feel. Now, many people will say that a puny 400 is too small for these subs, but I find that to be false. These subs are 2 ohm dual voice coil that are wired with a jumper for 4 ohms. I can't stay in the house with the system cranked, and the properly calibrated meters never come close to showing 40 Vrms output.
My main speakers are big JBL Millenniums, 8 ohms.
And another magic part of the system is the active crossover, a MiniDsp 2by4. The 400 S2 is given the subwoofer "slice" of the spectrum, and the 400 S1 gives the JBLs the other "slice" as defined by crossover parameters, filters, and equilization entered into MiniDsp. The result is a very efficient system. One is not working the amps sending the full spectrum to the sub, where the built in crossover separates the spectrum, generating heat with unused spectrum. My subs have no crossovers in them.
There is a learning curve with the MiniDsp software and Room Equilization Wizard program. But worth it in my opinion, especially if the system also integrates a big flat screen for watching movies and music video clips.
If your going to build subs, build two and dedicate a full WOPL to them. Freaking awesome.

 

[George S.]

Oops, I tend to get carried away, finally got the system I always wanted.
Active crossovers are the way to go. Many out there.
May as well dedicate a WOPL to sub duty. Since you can't easily bridge a WOPL, get two smaller subs rather than one big one. Two smaller are better than one big one anyway.

 

[MarkWComer]

Thanks- looks like I have some options to investigate!

 

[pennysdad]

Thanks- looks like I have some options to investigate!

If you wanna get really serious, go here: https://www.roomeqwizard.com/
There's some fantastic info and advice can be got from here: https://www.avsforum.com/forums/subwoofers-bass-and-transducers.113/

 

[George S.]

Oh. and my subs don't go boom, boom, boom like we've all heard from cars going by. They are fully integrated to supplement the main speakers seamlessly. You wouldn't know they're even working unless you look at the meters or feel the cabinet, yet turn the sub amp attenuators down and you'll hear and feel the difference.
This is the result of using a MiniDsp, REW, Umik-1 michrophone, to integrate the system to the room. It's what the home theater guys have been doing for years. REW generates data by doing room sweeps, this data can be inserted into the MiniDsp to calibrate it. Multitudes of YouTube videos on this.
Yes it gets complicated quickly. I work 60-65 hrs a week so I've only learned the basics, but it works great.
Also, there are other boxes for those Ultimax drivers like a Full Marty, but they are huge. So I went with the smallest. Even so, still huge and 4x4 legs under them.

 

[pennysdad]

Oh. and my subs don't go boom, boom, boom like we've all heard from cars going by. They are fully integrated to supplement the main speakers seamlessly. You wouldn't know they're even working unless you look at the meters or feel the cabinet, yet turn the sub amp attenuators down and you'll hear and feel the difference.
This is the result of using a MiniDsp, REW, Umik-1 michrophone, to integrate the system to the room. It's what the home theater guys have been doing for years. REW generates data by doing room sweeps, this data can be inserted into the MiniDsp to calibrate it. Multitudes of YouTube videos on this.
Yes it gets complicated quickly. I work 60-65 hrs a week so I've only learned the basics, but it works great.
Also, there are other boxes for those Ultimax drivers like a Full Marty, but they are huge. So I went with the smallest. Even so, still huge and 4x4 legs under them.

When I first came across REW a few years back, I totally freaked, 'cause that's exactly how I first 'saw' sound when I was having an acid trip back in the early 70's. ... & that's why I became a sound guy.

 

[George S.]

When I first came across REW a few years back, I totally freaked, 'cause that's exactly how I first 'saw' sound when I was having an acid trip back in the early 70's. ... & that's why I became a sound guy.

Great point! YES!

 

[BlazeES]

Gonna jump in here because Mark touched on something that helps to visualize the answer to the original question. Hope this helps Pennysdad and Lee...

Mark used the word "surface" earlier...

Without delving into the whole Fourier transfer function of complex audio signals and then how these things get processed in the human brain ... I'll leave that to Joe ...

This question of 'how' does a driver reproduce the complex sound we hear can be visualized this way.
(This question comes up a lot in psycho-acoustic discussions and in the measurement of mechanical acoustics, spL or sound in general...)

A common description is to try and illustrate a completely still body of water or pond, with pebbles & stones being tossed into it producing ripple or wave patterns.
I've gone farther and tried to use a big bass drum skin as a different take on it. In either case, assume the size of the rocks equate to the principal frequency tied to a big stone being a very low frequency signal source versus a super tiny, minuscule rock being a treble component, and then all the sizes in between. If you could drop a handle full of various sized pieces of rock into the still pond or onto the firmly stretched drum skin, all at the same time, that drop sums up to the complex wave form that forms an audio signal in a segment of time. When you visualize the resulting ripples in the pond example, the smallest of the disturbances are squelched by the progressively large pieces of stone or are seemingly (perceivably) non existant. In the case of the drum skin, the smallest pieces don't have the mass (or force) to even move the "surface", where as the progressively larger and larger pieces do. And they do so in an interactive way.

Forgot that a driver cone is conical. Think of it much like a flat surface in effect, with 'stiffness' being a big controlling factor, because that's the way it behaves in a rudimentary & mechanical way.

*

If this stuff is of any interest, I'd recommend people search out books or white papers on the internet on spring/mass systems and principals of acoustics.
A lot of them are digestible reading. And a wholly different approach is read up on the structure on the inner ear.

 

[pennysdad]

Thanks for that, but I've been through it all, but I still can't relate as to how in such a multiplex of frequencies and energy how the hell do we still have the ability to distinguish amongst all that's going on, the separate sound sources [instruments] all at the same time being produced by a cone of paper moving backwards and forwards in a magnetic field whilst being energised accordingly.
eg, strike a triangle and listen to it sustain. Record that. Now strike a guitar chord with lots of distortion. Record that. Now play them back both at the same time. How the hell can you still hear a triangle sustaining whilst there's a guitar crunching both at the same time through a single medium that's trying to reproduce BOTH sounds at the same time? You would think the cone would do one or the other if the note was to remain pure, but it doesn't, so therefore there must be some sort of trade off. And yet, there doesn't sound like there is, or is there?
Something's not 'clicking'. No amount of throwing pebbles in a pond watching waves propagate is letting me see it.
I need a bigger brain.

 

[pennysdad]

I had a setup for a while where I had 16 channels into 8 outputs which I then had each output go to it's own amp/speaker.
Then I played some multi tracks and gave each instrument it's own amp/speaker.
That was getting pretty damn good.

 

[George S.]

I've heard it said that all objects have a resonate frequency. If true, then different drivers would have differing resonate frequencies. Might the sounds we hear be harmonics of the resonate frequency of the driver?

 

[MarkWComer]

Thanks for that, but I've been through it all, but I still can't relate as to how in such a multiplex of frequencies and energy how the hell do we still have the ability to distinguish amongst all that's going on, the separate sound sources [instruments] all at the same time being produced by a cone of paper moving backwards and forwards in a magnetic field whilst being energised accordingly.
eg, strike a triangle and listen to it sustain. Record that. Now strike a guitar chord with lots of distortion. Record that. Now play them back both at the same time. How the hell can you still hear a triangle sustaining whilst there's a guitar crunching both at the same time through a single medium that's trying to reproduce BOTH sounds at the same time? You would think the cone would do one or the other if the note was to remain pure, but it doesn't, so therefore there must be some sort of trade off. And yet, there doesn't sound like there is, or is there?
Something's not 'clicking'. No amount of throwing pebbles in a pond watching waves propagate is letting me see it.
I need a bigger brain.

Throwing more mud into the water- the human eye can detect nearly 17 million colors, yet your TV screen only has red, green, and blue. Look at a yellow area closely and see that red and green are the brightest while blue is dim.

 

[George S.]

Gonna jump in here because Mark touched on something that helps to visualize the answer to the original question. Hope this helps Pennysdad and Lee...

Mark used the word "surface" earlier...

Without delving into the whole Fourier transfer function of complex audio signals and then how these things get processed in the human brain ... I'll leave that to Joe ...

This question of 'how' does a driver reproduce the complex sound we hear can be visualized this way.
(This question comes up a lot in psycho-acoustic discussions and in the measurement of mechanical acoustics, spL or sound in general...)

A common description is to try and illustrate a completely still body of water or pond, with pebbles & stones being tossed into it producing ripple or wave patterns.
I've gone farther and tried to use a big bass drum skin as a different take on it. In either case, assume the size of the rocks equate to the principal frequency tied to a big stone being a very low frequency signal source versus a super tiny, minuscule rock being a treble component, and then all the sizes in between. If you could drop a handle full of various sized pieces of rock into the still pond or onto the firmly stretched drum skin, all at the same time, that drop sums up to the complex wave form that forms an audio signal in a segment of time. When you visualize the resulting ripples in the pond example, the smallest of the disturbances are squelched by the progressively large pieces of stone or are seemingly (perceivably) non existant. In the case of the drum skin, the smallest pieces don't have the mass (or force) to even move the "surface", where as the progressively larger and larger pieces do. And they do so in an interactive way.

Forgot that a driver cone is conical. Think of it much like a flat surface in effect, with 'stiffness' being a big controlling factor, because that's the way it behaves in a rudimentary & mechanical way.

*

If this stuff is of any interest, I'd recommend people search out books or white papers on the internet on spring/mass systems and principals of acoustics.
A lot of them are digestible reading. And a wholly different approach is read up on the structure on the inner ear.

That has to be it, the "complex wave form". Those 3 words make it understandable.

 

[Gepetto]

Right back to the beginning

 

[pennysdad]

I've heard it said that all objects have a resonate frequency. If true, then different drivers would have differing resonate frequencies. Might the sounds we hear be harmonics of the resonate frequency of the driver?

The resonant frequency is generally tuned out by being either above or below the actual operating areas of the speaker's performance area.
Anyway, just woke up, and I'm off to my physio, but I'll leave you with this. Regarding throwing a pebble in the water, what you see is the response from just one pebble and only being thrown once. A very nice simple 'sine wave' but what if you threw a handful of pebbles all at the one time? What do you see now? A whole bunch of waves crashing into each other resulting in pandemonium. You have dominating waves from the biggest pebble, crashing into others and sometimes even cancelling them out. Starting to not look so simple now, is it?

 

[George S.]

But consider being at a pin point somewhere on the surface. You would be buffeted by a complex wave form. What's happening elsewhere on the surface I think wouldn't matter, what matters is the frequency and amplitude of the waves at that pin point.

 

[MarkWComer]

A whole bunch of waves crashing into each other resulting in pandemonium.

...that’s called a Yoko Ono album.