I'll have to reread all of that...

I use this:

http://www.etfacoustic.com/

Just that I can tell it what freqs to use for the test signal. (See, I have this thought that if I only pick specific signals that don't encompass my nulls, I can pretend they aren't there... )

Because of the slopes, I do figure I can improve to 120 Hz with a 60 Hz crossover, but maybe up to 160 Hz with an 80 Hz setting potentially by adding another sub.

[This message has been edited by Kevin C Brown (edited August 14, 2004).]

BoB- I am intrigued by your "movie" sub vs "music" sub idea.

Right now, I have 1 Vandersteen V2W sub. Kind of meant for "movies" in that it only has an RCA input.

Vandersteen also has the 2WQ, which is kind of meant for "music", in that it has an adjustable Q, and a unique way of crossing over with the mains. Both have 3 8" drivers, but the V2W also has a 12" passive radiator.

More info here (it's a quick read):

http://www.vandersteen.com/pages/Pdffiles/2wlit.pdf

So one question is:

a) 2 V2Ws. Just send each a mono signal with a Y splitter.

b) 2 2WQs. In this case, I'd use the speaker level way of connecting them, use one for each front speaker, and then set up the pre/pro to be L & R large, no sub, and center/surrounds/rears all small. So all the bass gets rerouted to the mains with the subs.

c) A V2W and a 2WQ. I'd run the V2W with the bass from the surrounds, rears, center, and LFE and the 2WQ with the bass from the L & R. (The music sub and movie sub idea.)

Also, I know that a corner is the most recommended location. But based on standing waves and such, is there any way to say what the next best location would be?

I.e., on Harman International's web site, they suggest that 1/2 down opposite walls is a good place for two subs. (That 1/2 point is a null, so subs there would eliminate it, right?) But they actually didn't test a corner and 1/2 down a wall.

http://www.harmaninternational.com/wp/index.jsp?articleId=1003

The Vandersteen subs are kind of heavy, 80 lbs each, but I'm actually toying with the idea of getting 2 "cost effective" subs (would have to be 50 lbs or less) and just experimenting a bit. In that case, I'd actually be able to try out 3 subs. (And yes the Outlaw sub is a candidate. )

Any thoughts?

Here are 2 alinks to articles on placement that I found helpful:

here

and

here

The best setup, of course, would be 2 of the 2Wq subs in a stereo redirected bass setup and 1 of the V2W for LFE only.

If you run the analog SW out of the player for LFE only (using the player's DACs), when you switch to digital (the pre's DACs), the LFE will be inserted into the 2Wq sub or subs as well as the LFE sub, equalling a 6ish dB boost for flicks.

I forget what pre you have (MC-8 if memory isn't totally fried)??

The info you linked is a bit confusing, in that it describes the 2Wq as 'second order, slot loaded' and having adjustable 'Q' from .5 to 1.2. Hmmmmmm...second order is a sealed design, whereas slot loaded is a 4th order ported design which would make 'Q' adjustment over that much of a range difficult.

Maybe you can help me with V's terminology.

The 2WQ is sealed, and the V2W is slot loaded.

Cool, thanks for those links. Will take me a bit to digest those.

BoB- Interesting articles.

I like the first one's suggestion of the 1/3 octave pink noise and pitch method of adjusting for phase. (I have to see if I can track down those two discs.)

The HT mag article seems to contradict a lot about what I've heard for sub placement. I wish he could have included some real world measurements in terms of how the anti-node placement works vs a corner for example. And I assume that if the sub goes on an antinode, the listener goes on a node. I'm not sure about the WAF for his suggestions for placement though!

obviously true... i guess if one cant tell if one sub is better than another (2x for example), then one wouldnt notice the difference between 2 or 1... if the user is indiscrimant then the point is moot altogether.





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This post has been brought to you by curegeorg, thanks for reading.

Yes, that's why I'm curious as to people who've actually used an RTA to look at the impact of the 2nd sub. For someone to say, "I have two subs and it's much better than one" doesn't really mean much. They might just like saying "I have 2 subs".

In my case, I can say with all certainty that 2 subs are better than one, without any measurements.

Since one sub is discrete .1 and the other is discrete redirected bass, 2 subs is necessary to complete playback of any X.1 format.

Of course, with 2 channel or any .0 format, I actually only have 1 sub.

For those who have the time and aptitude for it, there is some excellent information to be found at:

http://www.harman.com/wp/index.jsp?articleId=120

One of the papers referenced at that link is:

http://www.harman.com/wp/pdf/multsubs.pdf

For those that want the conclusions first, in the room used for testing:

How many subwoofers are enough? – Four subwoofers are enough to get the best results of any configuration tried. Two subwoofers are very nearly as good and have very good low frequency support as well.

What is the optimal placement? – If cost and aesthetics are considered, subwoofers at 2 wall midpoints are preferred.

Approaching another aspect of ‘subwoofering:’

http://www.harman.com/wp/pdf/Loudspeakers&RoomsPt3.pdf

I found, by my personal mix of rudimentary objective measurement and subjective listing that:

Two subs are better than one, especially in real world, far-from-ideal listening environments. Depending on the type of music being played back, operating two subs in stereo instead of dual mono may have some benefit, and would likely have that benefit only for certain ‘live’ recordings where stereo bass was recorded in the first place and preserved through to the final playback medium.

There is no substitute for learning some basic subwoofer placement principles beyond what is found in most owner’s manuals and taking a good deal of time to experiment with subwoofer placement in your particular environment. The subs' output level must also be very carefully tweeked. There is no universal, ideal, single solution for every environment.

In my listening environment, with a convoluted arrangement of walls and spaces adjacent to the media room, I have found the following helpful:

A slightly asymmetrical placement of two subs means both subs are not exciting exactly the same nodes in the same places and helps reduce the places were bass is either boosted or suppressed by multiple standing waves affecting the same point within the listening area. (I have worked for the best listening overall in a listening area, not just a single ‘prime location.’ If using parametric EQ, this would mean using multiple sampling locations.)

A change in the position of a subwoofer by as little as three inches can produce a noticeable change in listening results.

I ‘de-couple’ the subwoofer cabinets from my ‘flexible’ flooring with some ‘cushioning.’ (Contrary to what much product ‘hype’ says, most spikes actually increase the physical coupling of a loudspeaker’s cabinet vibrations to the flooring. It’s physics.) This helps the ‘sounding board’ flooring in my situation to be more of an acoustical absorber and less of an acoustical generator.

I've experienced no problem with mixing .1 channel bass with the redirected stereo/mono bass from other channels via an Outlaw ICBM. My adjustment goal was that musical instruments with solid bass content would sound as they should - the low fundamental frequencies coming from the subs blending properly with the remainder of that instrument’s sound that come from the other loudspeakers in such a way that the original character of the instrument is faithfully reproduced. Once my painstaking pursuit of the correct music sound was as complete as I could make it, I found the reproduction of DVD movie material fell right into place without modification. I make no changes to the subwoofer setup as I switch between music and theatrical release.

Be patient, don’t be afraid to try different (non-destructive!) things.


[This message has been edited by bestbang4thebuck (edited August 24, 2004).]

>>>Yes, that's why I'm curious as to people who've actually used an RTA to look at the impact of the 2nd sub. For someone to say, "I have two subs and it's much better than one" doesn't really mean much. They might just like saying "I have 2 subs". <<<

Two or more subs excite more of the natural room modes, and at different frequencies. This causes the peaks and dips caused by these modes to be of less amplitude overall depending on placement - one sub may excite a strong "peak" while the other creates a "dip" at that frequency at the listening position, effectively reducing or eliminating the original peak.

More than one sub will equate to more efficiency (overall output by +3db over a single sub) and they will exhibit a lower extension of low frequency response than one sub alone - this is caused by mutual coupling which essentially makes two subs seem like one larger one if they are positioned relatively close to each other at the lowest frequency's wavelength. If one of your subs have a low frequency extension of 25Hz for instance, two subs could have extension to 20-22Hz or so.

These are real world and measureable benefits.

[This message has been edited by soundhound (edited August 24, 2004).]