Two Channel Stereo + subwoofer (small room)

[kach22i]

Do your research, and hopefully you will soon realize that most of the articles and videos out there are catering to the home theater crowd or large stereo rooms (hence the multi-sub approach).

This means they are trying to get good bass almost everywhere when you are flying solo and only need it where your chair is at (the studio mixing room articles might actually be more applicable).

This is a HUGE difference, after all it's 2-channel stereo and not 5.1 or 7.1 HT with a dedicated channel already optimized.

However you can make it 2.1 with a rack mounted crossover after the preamp, I did not go that route.

Good news is some of the basic acoustic principals apply to your small room, a one or two person sweet-spot listening room.

So if you have one old sub, then you are in luck, I have a solution that just might work for you.

Using the KISS Method I'll start with some pictures (see below).

Video/article-1:
Ideal Subwoofer Placement & Pressurization – Acoustic Fields

White Paper:
Soundoctor - all about subs

Thread on subwoofer crossovers cause phase issues:
Subwoofers and Time Relationships | What's Best Audio and Video Forum. The Best High End Audio Forum on the planet!

Add it all up..........

1. Must get subwoofer away from walls.

2. Subs are more directional than advertised.

3. LP and CD bass is mono (recording engineer claimed so - read White Paper)

4. Try inverting/switching IC wires going to subwoofer.

5. Better to use Low Level inputs (interconnect cables) from dual output preamp than hooking up with speaker wires via High Level Inputs.

6. In all cases experiment and find what works for you, I only know what worked for me in my room - results may vary.

Picture of my dark room below, a work in progress.

What you see is the loudspeakers in typical position, with chair set back a little from sweet-spot just like dipoles are supposed to be, but the subwoofer is actually in a near-field listening position because bass wavelengths are so long. This is called a "pressure zone" listening position where you heard the sub first, and not the room.

My settings are near the minimal volume level, and crossover frequency also near the 37 Hz minimum.

The sound of a drum kit is dead center and at the proper height too.

The less junk you have between your speakers and on the front wall the better your sound-staging should be. My equipment rack on the right is scheduled to be moved out of there when I remove the closet wing-wall to the left. Then the speakers can be moved farther apart, and my seat set further back. I might have to adjust toe-in again at the same time.

It pained me at first to put the sub in the middle, but acoustics above convenience.


Good luck and happy listening.

 

[kach22i]

One thing perhaps not made clear enough in the opening post is that the fewer things located in between the speakers (excluding subwoofer) the better, as anything in the middle will interfere with sound-staging.

Something in between the speakers like mono-amps on platforms or a low slung sub are less of a problem.

Items do not have to be at ear level to be of nuisance, the reason being that driver radiation patterns are not 2D FLAT as seen in polar radiation charts, the lobes are 3D.

This means the AIR adjacent, below and above the driver are part of the sonic presentation, and if you nibble into it, it's like a half eaten pie.

You want the WHOLE pie, don't you?

This phenomena may be more present in dipole and panel speaker than conventional dynamic drivers, and even less present in typical horn speakers, however it should not be ignored in any of them, in my opinion.

Radiation pattern varies with frequency (usually).

https://realtraps.com/art_front-wall.htm

Move your audio rack off to a sidewall if you can (it's in my plans), and not at a first reflection point if you can help it.

 

[tcdriver]

That does look like a small room. What are your current room dimensions?

 

[Hyfi]

Many of us do not have the ability to have nothing between speakers unless we have dedicated rooms, I don't.

As far as bass goes, one can always get speakers that excel in good bass and drive them with an amp that can handle it as well. I could integrate a sub in my system and have in the past, but I don't feel the need because clarity is more important than just deep bass if it is not fully controlled and properly integrated into a tuned room.

 

[BOUXY]

Well I don't need or use any Subs. My speakers are stereo and dig deep enough! Explain to me how a sub/only one can play say Bass that comes from the right or left side only or as a solo from one side only in stereo?

 

[illinoisteve]

Couldn't you just put the subwoofer under the couch?





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[E-Stat]

One alternative is to place the sub(s) behind you. I tested that concept on a whim using very long interconnects and measured the difference. Was able to achieve more linear results than with the subs adjacent to the mains. I ended up purchasing Emotiva "Virtual Copper" devices for a wireless connection (little device on floor at left with blue LED). I faced each sub to the side. That also freed up space between the mains for a more open environment especially since the Acoustats/Magnepan center are dipoles like the OP's M-Ls.

 

[spark1]

Well I don't need or use any Subs. My speakers are stereo and dig deep enough! Explain to me how a sub/only one can play say Bass that comes from the right or left side only or as a solo from one side only in stereo?

A single sub gets both right and left channel input. The sub handles the lowest frequencies, which are fairly non-directional. The mains provide the imaging/stereo effect (keep in mind that most low frequency sounds being primarily handled by the sub also have higher frequency elements being reproduced by the mains). Works pretty well, altho I've found stereo subs to do a somewhat better job of it.

 

[kach22i]

That does look like a small room. What are your current room dimensions?

7'H x 11'W x 22'L soon to be 15'-6"L with a door in each rear corner.

Doors will be sliding type, and since bass loads up in rear corners most, if I have issues will just crack them open a bit.

Because of time delay caused by typical subwoofer crossovers a foot rest or coffee table subwoofer is a pretty good idea - seen at least one posed before.

I did some work to the room and was able to get speakers 6 inches more apart. Removed most of closet wing wall on left, corner post still there.

It took some doing but I now have sketches that will allow for equipment on side walls. Working to keep the front wall relatively clear and open is work, but all the best systems seem to do this. Horns are more forgiving of this as I understand, flat panels least forgiving.

 

[kach22i]

Well I don't need or use any Subs. My speakers are stereo and dig deep enough! Explain to me how a sub/only one can play say Bass that comes from the right or left side only or as a solo from one side only in stereo?

Read the white paper.

In short, my main speakers are being run full range with sub taking up only what the mains cannot.

White paper explains recording process, bass really low is mono.

If you crossover at higher frequencies and restrict signal to mains or have one of those $3,000 JL Audio crossover boxes after the preamp I can see two subs or more being an advantage.

Personally I would rather put my money into improving the room and keep my signal as unmolested as possible

 

[spark1]

How does using a high pass filter molest the signal?

 

[JoeESP9]

Any added circuitry active or passive has the potential for "molesting" the signal.
FWIW: I use a stand alone electronic crossover between my main amplifiers and dual subs amplifiers (4 mono blocks).

 

[spark1]

Then the best approach must be speakers with only one driver (no crossover), and a subwoofer that rolls off mechanically. Wonder why that arrangement is not the norm?

Thankfully, I am happy with my molested sound system...though I am sure it would not pass muster with those in the know.

Hey OP, do your main speakers incorporate any kind of crossover?

 

[JoeESP9]

The only single driver speakers that sound right to me are full range electrostatics. IME Magnepans up to and including the 1.7's come close because the bass, midrange and tweeter sections are all on the same diaphragm.

 

[kach22i]

Spark1, all the hybrid Martin Logans not only have crossovers but that thing which allows the stators to be charged so the signal can be fed.

About 10 years ago I built several prototype speakers, the 6th edition being single full range. However with the flip of a toggle switch the tweeter with an L-Pad and single cap to limit lower frequency and protect tweeter could be engaged.

This was an exercise that taught me that even though I could draw the wiring, it took me four times to hook the wires up properly.

I make drawings for a living, who knew following them is a different skill?

In Barry Ore's white paper (Sound Doctor) he says do not worry about crossovers (and time delay of mains) molesting your precious signal. If you only knew how many mics, wires, mixing boards, caps, resistors and so forth you would know it isn't so precious.

I would guess Jack White's direct to vinyl project using 1930's practices as the exception.


https://thirdmanrecords.com/locations/nashville-storefront

......and the world’s only live venue with direct-to-acetate recording capabilities. Third Man.......

 

[kach22i]

Any added circuitry active or passive has the potential for "molesting" the signal.
FWIW: I use a stand alone electronic crossover between my main amplifiers and dual subs amplifiers (4 mono blocks).

Can you please start a poll with another thread?

I'm assuming most people do not use and may not even know about electronic delay crossovers.

I am asking that someone else do this as I have to open up my laptop and repair where the power port comes in.

I am on my cell phone now.

A simple poll of crossover or no crossover, or perhaps a more telling poll is that of 2-channel stereo with sub, who uses crossover to restrict signal to mains and add delay to mains.

As I understand it there are no subs with these features built in, and those who think they are, are mistaken.

 

[SterlingOne]

There are it seems many factors which will enhance or preclude satisfaction with recorded music which has low frequency content. I have two systems which manage bass:1. Sony TA-E9000ES Pre-Pro manages bass for stereo material from all sources. 2. Sony TA-P9000ES 6 channel Analog Preamplifier receives 5.1 analog from OPPO-205 which manages bass for multi-channel material from all sources.. Each of these systems can manipulate bass as much as it can be manipulated for an effect on music and movies that sounds just right; but, there is a caveat, low volume requires bass emphasis and high volume requires bass deemphasis, which is simply a hassle.

 

[Grenadeslio]

Then the best approach must be speakers with only one driver (no crossover), and a subwoofer that rolls off mechanically. Wonder why that arrangement is not the norm?

Thankfully, I am happy with my molested sound system...though I am sure it would not pass muster with those in the know.

Hey OP, do your main speakers incorporate any kind of crossover?

See, it's not so cut and dry. My main sub has an outboard external control unit that's very flexible, it even incorporates a variable high pass through a selection of different dip switches. I've used it this way but feel the soundstage is improved without. This way my amplifier receives the signal as it left the preamp without going through "more" electronics in the signal path.

 

[E-Stat]

Then the best approach must be speakers with only one driver (no crossover), and a subwoofer that rolls off mechanically. Wonder why that arrangement is not the norm?

There is no one best approach given different listener priorities and room characteristics. Full range speakers available today that do first octave bass run $45k+.

Thankfully, I am happy with my molested sound system...though I am sure it would not pass muster with those in the know.

FWIW, the small Acoustats used in the HT are high passed at 80 hz (along with some parametric EQ attenuation slightly above that ) for improved dynamics and the most linear in-room response.

Hey OP, do your main speakers incorporate any kind of crossover?

The xover frequency to the 8" driver on the Aerius is 500 hz.

 

[Grenadeslio]

Can you please start a poll with another thread?

I'm assuming most people do not use and may not even know about electronic delay crossovers.

I am asking that someone else do this as I have to open up my laptop and repair where the power port comes in.

I am on my cell phone now.

A simple poll of crossover or no crossover, or perhaps a more telling poll is that of 2-channel stereo with sub, who uses crossover to restrict signal to mains and add delay to mains.

As I understand it there are no subs with these features built in, and those who think they are, are mistaken.

But there are plenty with variable high pass and variable phase control for the sub which is effectively the same thing eh?