Possible benefits of "stereo" subs? (1 Viewer)

[Tom Vodhanel]

I agree, if I find something I like but it's not considered *accurate*(like having the subwoofer up a few dBs)...who cares...it's what I like!

But I think it's important to know the difference between a simple preference and what would be considered the most accurate presentation possible.

TV

 

[Bob_A]

Don't get me started about preferences vs. "accuracy", Tom

 

[BruceD]

Bob,

I'm assuming from your quote that follows that your mains include powered subs.

quote:

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"But let me just say...given some room to breathe on the sides, these built-in "stereo" subs are awesome."

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You may like this and it may be your preference, and certainly some manufacturers are pushing it, but it has to be the worst implementation for good bass of anything I've heard in recent years.

You just can't optimize a single speaker cabinet in a single location for both midrange/highs imaging and optimum low bass reproduction.

You simply compromise one or the other, which is why a separate subwoofer is a much better choice especially for HT.

For all those deciding what to audition and buy, this is probably a good rule to remember, as well as buy what sounds good to you.

 

[Bob_A]

If you heard my setup, I doubt you would be saying that

 

[John Kotches]

Perhaps I'm mistaken here, but I do believe we're dancing around the topic without actually getting there.
We need to distinguish between stereo subwoofers and multiple mono subwoofers.
Taking a subwoofer output and splitting it to two seperate subwoofers is not stereo subs.
In the HT context, stereo subwoofers would be this:
Left Sub: Left Front Low Pass, Left Surround Low Pass, 1/2 CC Low Pass, 1/2 LFE.
Right Sub: substitute the word Right for Left.
You have potential cancellation issues between the subwoofers that must be addressed carefully or you could end up with a frequency response nightmare.
Multiple mono subs, is another story altogether.
I think TV is playing with such a configuration, as he has a dedicated LFE sub (mono) and 4 other subs, probably attached to each front and back speaker. So, each of the 4 speakers would have a dedicated subwoofer, to extend it to full range. Ahhh to get to play in Tom's lab, for just a day
Regards,

 

[Tom Vodhanel]

John,

I actually started out like that years ago. Trying to run a woof on each channel even.(nothing like a Infra to handle the center).

The results were so poor after I spent so much time on it...I realized I would never get this to work well.(and I'm talking literally 100s of hours spent tweaking multiple EQs,XOs and sub/listener placement with a couple of RTAs running full time.

Now, I'm running a MC-12 using it's *stereo* bass outputs. Lexicon is doing some interesting phase stuff trying to minimize the inherent degradations involved here...but it's not the panacea some claim.(although it appears to be a step up from the earlier *bass enhance* I measured on the DC_1 and MC_1) What they do is take the RF,RS,RR and send it to the right sub,same for the left side...and they split the center. With the crossover flexibility now(30-100hz)...it's easy to try multiple variations. I haven't had the time to measure the phase games from each channel yet...but there is a subjective improvement in some regards on SOME material. I have one good woof for the LFE...and 4 others...2 for each *stereo side*.

I'll probably have it optimized just in time for the MC-22...sigh,

TV

 

[Kevin C Brown]

Bob- Have you ever *measured* the bass freq response of your system? SPL meter and a test disc that focuses on lower freqs? Or, using a PC with RTA software with a microphone hooked up?
I did the former for the 1st time a few months ago. Very enlightening. You may think your system sounds really good, but maybe it could sound even better!
Hey John: I think that I also figured out that stacking 2 stereo subs in a corner would be almost exactly the same as stacking 2 mono subs in that same corner. Whether you get phase cancellelation electrically (in the mono sub case) or acoustically, because the 2 signals are originating at more or less the same exact location in the stereo sub case, don't matter much none.

 

[Bob_A]

I hear ya Kevin...I was just too lazy to do it with a meter

 

[Richard Burzynski]

John & Others:

You touched on something that's been on my mind: stereo subs vs. mutiple mono subs.

If you had to work with the following layout, due to room furniture constraints:

sub * leftmainspeaker * rack * tv * rack * rightmainspeaker * sub

I have a choice and ability to properly implement stereo bass, or I can run multiple (split) mono. Assuming the fixed location of the above-referenced layout, which is more preferable: multiple mono or stereo.

The one thing that gets me is, if you consider someone who has "large" speakers (that go down into the 30 hz range) in a 2 channel system. If you get all these cancellation problems with lower frequencies why does the market for full range towers still exist? Why haven't all the 2 channel guys switched to sub/sat systems? They are amongst the most anal when it comes to tweaking the "sound" of their systems and they usually swear by them, inherent stereo bass and all.

Not trying to stir the pot here, I just really want to understand.

Thanks.

Rich B.

 

[AjayM]

Before you say things like,

If you heard my setup, I doubt you would be saying that

You really ought to measure it and find out what it looks like on paper.

I thought my system sounded really good (and well, it did), but then I measured and corrected some problems in the bass region and it's WAY better. I'm talking about those funky audiophile words, detail, articulation, etc with regards to bass.

My setup was pretty good with a couple of big peaks and one nice hole of a null. Basically at 28Hz I was normal, at 30Hz I was -8db at 35Hz I was +2db and at 40Hz I was +10db.

Now I still have a +4db peak at 20Hz, and still a -4db null at 30...the null I think is never going to go away, the peak is easy to get rid of. The rest of the response is probably +/- 1-2db...and the result is incredible.

Andrew

 

[Kevin C Brown]

Ajay, you and I should invite ourselves over to Bob's place and get him motivated to measure.
My experience echo's yours. Ended up getting a BFD eq to at least try to fix a lot of my problems.
And, I also found the phase adjustment I tried to do by ear was completely off when I actually measured the spectrum through the cross-over point.
Much smoother response now.

 

[Bob_A]

LOL Kevin...then you guys will need to buy the beer

 

[BruceD]

I agree Kevin, measuring the room/speaker response characteristics and then correlating your measured results with what you hear is a very informative process.

It opens up a new understanding of how different settings and parameters affect what we actually hear.

 

[Kevin C Brown]

Bob- Ya got a 7-11 near you? I'll pick some up on the way... Hee, hee.

 

[Bob_A]

 

[Tom Vodhanel]

>>>I agree Kevin, measuring the room/speaker response characteristics and then correlating your measured results with what you hear is a very informative process.

It opens up a new understanding of how different settings and parameters affect what we actually hear.

 

[John Morris]

Ayup,

This must be TV's attempt at mastering the upper NE dialect just before he tries his hand at fishing the Outer Banks. Hmmm, or is that actually Minnesotan dialect? Ahhhh, it must just be SVS dialect!