Room Gain and subwoofers

[KEW]

This thread is a spin-off from another thread which I did not want getting lost from this off-shoot.
I know ShadyJ and I can have an active exchange which can obscure what may be a more important more slowly developing discussion so want to keep them separate (though they are closely related).

The problem here is that you can't really be certain what the room will do to the bass. Sure, if you are in a small sealed room, you can count on some low frequency gain, and in that case, get a sealed sub- if a flat response in room is what you are after. But, of course, such a room is not always the case, and there is also those who might prefer a boost in deep bass anyway. With respect to low frequency headroom, I would rather have it and not need it than need it and not have it.

Well, someone could download download REW, buy a mic and either borrow (or purchase with return policy) a sub that has been thoroughly measured by Josh (or your recent measurements). Once he determines the location of the sub and his LP, he could then take measurements and compare his in-room response to the results to determine room gain. That would take time and effort, but has the potential to save money. Maybe I'm wrong, but I think it is an idea worth floating. It also seems like mathematical modeling might be effective for any room which is a simple box (IOW, no vaulted ceilings open to second floor or open to foyer, etc.

Pressure vessel gain typically starts where the longest dimension of the room meets one half the frequency wavelength, so for a 22' long room, the 1/2 wavelength is about 25 Hz, so maybe that is where you can expect pressure vessel gain to begin to compound low frequency output. What option will suffice depends on what the listener wants, like how loud, how low, how flat of a response. You will have to give me more specific criteria.

I realize that is ultimately the best answer, but I am not looking at a specific case and don't want to go down a road of detailed speculation which will ultimately lose traction as a worthwhile generalized discussion. For now, let's keep it in the spirit of your earlier post:

I would prefer subwoofers to have a default flat response and don't think manufacturers should make presumptions about the size of the user's room. The best thing to do is have the sub have a range of frequency response curves to choose from, like SVS's Ultra subs or Hsu's subs. Let the user decide what sounds best to them.

The best thing to do is have the sub have a range of frequency response curves to choose from, like SVS's Ultra subs or Hsu's subs. Let the user decide what sounds best to them.

Lastly, what are your thoughts on Audyssey as a tool to tune subs? Many believe that is where Audyssey is most beneficial. Have you looked at it much, or enough to understand its benefits and its limits?

 

[Halon451]

Lastly, what are your thoughts on Audyssey as a tool to tune subs? Many believe that is where Audyssey is most beneficial. Have you looked at it much, or enough to understand its benefits and its limits?

I'm following your posts because bass management and sub-related stuff is an area where I'm still on quite a learning curve as far as nitty gritty technical details and in-room responses. I've had my own issues integrating my long-time SVS sub into my new Marantz powered system utilizing Audyssey and even started a whole thread on Audyssey alone. It seems that some have found great success in letting Audyssey manage frequencies at the subwoofer level, but I for one, have found that it is a bit lacking. I had an older Pioneer Elite that had a nifty feature built into its MCACC program that dealt with standing waves. I confess I have no earthly idea how or what it did at the technical level to counteract the effects of standing waves but it seemed to do it quite well. Audyssey on the other hand seems to focus more on time, phasing and EQ and I'm not sure that anything in that mystery black box known as Audyssey corrects for standing wave issues. As such, I have a pretty good low end response in my room, but it seems a bit more "loose" and boomy than it ever did before, at least with some content. Something is missing and I don't know what, and I've run Audyssey multiple times with different mic placements. Whether it's the standing wave control or something else, in my experience MCACC seemed to do a bit better job at managing the bass, and Audyssey seems to be much more adept at handling EQ and room corrections for the rest of the speakers. Never one package that does everything perfectly is there...

 

[Halon451]

Sorry unless you're talking about the Audyssey stand alone kit. In that case I'll step aside on the topic and read/learn from others. I just naturally assumed you meant AVR-based Audyssey.

 

[KEW]

I'm following your posts because bass management and sub-related stuff is an area where I'm still on quite a learning curve as far as nitty gritty technical details and in-room responses. I've had my own issues integrating my long-time SVS sub into my new Marantz powered system utilizing Audyssey and even started a whole thread on Audyssey alone. It seems that some have found great success in letting Audyssey manage frequencies at the subwoofer level, but I for one, have found that it is a bit lacking. I had an older Pioneer Elite that had a nifty feature built into its MCACC program that dealt with standing waves. I confess I have no earthly idea how or what it did at the technical level to counteract the effects of standing waves but it seemed to do it quite well. Audyssey on the other hand seems to focus more on time, phasing and EQ and I'm not sure that anything in that mystery black box known as Audyssey corrects for standing wave issues. As such, I have a pretty good low end response in my room, but it seems a bit more "loose" and boomy than it ever did before, at least with some content. Something is missing and I don't know what, and I've run Audyssey multiple times with different mic placements. Whether it's the standing wave control or something else, in my experience MCACC seemed to do a bit better job at managing the bass, and Audyssey seems to be much more adept at handling EQ and room corrections for the rest of the speakers. Never one package that does everything perfectly is there...

Sounds like you are farther down that path than I, but from what I have read and seen, mini-DSP or Anti-mode both seem pretty capable and may be the better solution.
Tom V. of PSA used to sell both with his subs, but dropped the mini-DSP (used with REW) because most customers wanted the more simple "plug and play" solution of the Anti-mode. However, I suspect that the mini-DSP is more satisfying to an audio geek because we can see and understand where we started and what was changed to reach the end result (and have more control over those changes).

 

[KEW]

Sorry unless you're talking about the Audyssey stand alone kit. In that case I'll step aside on the topic and read/learn from others. I just naturally assumed you meant AVR-based Audyssey.

You were right the first time, I'm talking AVR Audyssey.

 

[Halon451]

Sounds like you are farther down that path than I, but from what I have read and seen, mini-DSP or Anti-mode both seem pretty capable and may be the better solution.
Tom V. of PSA used to sell both with his subs, but dropped the mini-DSP (used with REW) because most customers wanted the more simple "plug and play" solution of the Anti-mode. However, I suspect that the mini-DSP is more satisfying to an audio geek because we can see and understand where we started and what was changed to reach the end result (and have more control over those changes).

I've been looking at the miniDSP option myself, but I have questions. I won't hijack your thread with those questions, but it seems that you may have some of the same questions as I. Maybe those questions would be of value here. Also I haven't heard of Anti-mode.

See, I haven't been active on this forum in a long time, but coming back I realize how much I've missed learning new things.

 

[William Lemmerhirt]

I've been looking at the miniDSP option myself, but I have questions. I won't hijack your thread with those questions, but it seems that you may have some of the same questions as I. Maybe those questions would be of value here. Also I haven't heard of Anti-mode.

See, I haven't been active on this forum in a long time, but coming back I realize how much I've missed learning new things.

Trying not to derail this so I'll contain this in your quote lol.
Fwiw, I find the anti-mode, while effective, overpriced. As Ken said too, it's not as granular.
I've been using a behringer feedback destroy to EQ my 3 subs. Works great once you get past the vacuum like learning curve.
I'm also going to add to your NiN story on the other thread. I've experienced very similar things.

 

[Halon451]

Trying not to derail this so I'll contain this in your quote lol.
Fwiw, I find the anti-mode, while effective, overpriced. As Ken said too, it's not as granular.
I've been using a behringer feedback destroy to EQ my 3 subs. Works great once you get past the vacuum like learning curve.
I'm also going to add to your NiN story on the other thread. I've experienced very similar things.

I'd like to read your experience on that.

I'm familiar with Behringer products on the pro-audio side as far as live music equipment is concerned. Never used any of their products for my home audio setup. At least from the pro-audio side I know them to be of good quality.

 

[shadyJ]

Well, someone could download download REW, buy a mic and either borrow (or purchase with return policy) a sub that has been thoroughly measured by Josh (or your recent measurements). Once he determines the location of the sub and his LP, he could then take measurements and compare his in-room response to the results to determine room gain. That would take time and effort, but has the potential to save money. Maybe I'm wrong, but I think it is an idea worth floating. It also seems like mathematical modeling might be effective for any room which is a simple box (IOW, no vaulted ceilings open to second floor or open to foyer, etc.

Lol, believe me that is a lot more work than any casual hobbyist would want to do. Yes, you can determine room gain like that though. That is what organizations with anechoic chambers do to get measurements below frequencies where the wavelengths are larger than the distance to room surfaces; they make compensation curves referenced to groundplane measurements. But what are the savings in going through with that for an average audio enthusiast? I would say it's a lot easier to get a very capable subwoofer that can handle any type of room. The price difference between a ported sub vs sealed sub when all other things are equal is not that great. Compare the prices of the ULS-15 mk2 to the VTF-3 mk5 or the SB-2000 to the PB-2000.

I realize that is ultimately the best answer, but I am not looking at a specific case and don't want to go down a road of detailed speculation which will ultimately lose traction as a worthwhile generalized discussion. For now, let's keep it in the spirit of your earlier post:

So if the question is what is the least expensive option that has a range of responses that can tackle different rooms, off the top of my head I can say the Hsu VTF-1 mk3, which is a bit over $400. But the truth is you can plug the port on any bass reflex subwoofer which will roll off the bass in the 40s or high 30s, and that might accomplish what you are after: eliminating too much boost through room gain below 30 Hz.

Lastly, what are your thoughts on Audyssey as a tool to tune subs? Many believe that is where Audyssey is most beneficial. Have you looked at it much, or enough to understand its benefits and its limits?

I think taming peaks in bass is probably Audyssey's only real value, aside from automatically setting the phase correctly between speakers and subs. I wouldn't use it to 'tune' subs exactly, and that could turn into a problem, like what might happen if audyssey tries to boost the low end of a sealed sub in a room that isn't getting any low-frequency gain; it becomes very easy to overdrive that sub. If there is way too much low end gain, as you know, Audyssey can only cut down on that so much as well. The usefulness of Audyssey in shaping the low end only goes so far, but it's certainly better than nothing.

 

[lovinthehd]

Sorry unless you're talking about the Audyssey stand alone kit. In that case I'll step aside on the topic and read/learn from others. I just naturally assumed you meant AVR-based Audyssey.

Well, it's still avr based if you're talking about the Audyssey Pro kit, usually restricted to the top end avrs and it still costs extra (and is now being phased out of avrs and newer app based technology being phased in). At least I don't think there's a true stand alone kit from Audyssey....

 

[KEW]

Lol, believe me that is a lot more work than any casual hobbyist would want to do. Yes, you can determine room gain like that though. That is what organizations with anechoic chambers do to get measurements below frequencies where the wavelengths are larger than the distance to room surfaces; they make compensation curves referenced to groundplane measurements. But what are the savings in going through with that for an average audio enthusiast? I would say it's a lot easier to get a very capable subwoofer that can handle any type of room. The price difference between a ported sub vs sealed sub when all other things are equal is not that great. Compare the prices of the ULS-15 mk2 to the VTF-3 mk5 or the SB-2000 to the PB-2000.


So if the question is what is the least expensive option that has a range of responses that can tackle different rooms, off the top of my head I can say the Hsu VTF-1 mk3, which is a bit over $400. But the truth is you can plug the port on any bass reflex subwoofer which will roll off the bass in the 40s or high 30s, and that might accomplish what you are after: eliminating too much boost through room gain below 30 Hz.

I think taming peaks in bass is probably Audyssey's only real value, aside from automatically setting the phase correctly between speakers and subs. I wouldn't use it to 'tune' subs exactly, and that could turn into a problem, like what might happen if audyssey tries to boost the low end of a sealed sub in a room that isn't getting any low-frequency gain; it becomes very easy to overdrive that sub. If there is way too much low end gain, as you know, Audyssey can only cut down on that so much as well. The usefulness of Audyssey in shaping the low end only goes so far, but it's certainly better than nothing.

Would the VTF-1 accommodate the room size I mentioned properly, if so (and if the flexibility allows it to be properly tuned), this does seem like a dead end.

Thanks for your thoughts on Audyssey, that is pretty much my experience. I have seen it do good things with poor speakers, but with good speakers, I have less confidence it is improving the sound. In the bass; however, I feel good about what it does. The comments about the Pioneer system above are pretty intriguing!

 

[lovinthehd]

I would say it's a lot easier to get a very capable subwoofer that can handle any type of room. .

I think this sums it up nicely in many ways, although I wouldn't necessarily say just one sub to suffice.

 

[lovinthehd]

The comments about the Pioneer system above are pretty intriguing!

That gentleman also has his couch right up against his wall....in a room with challenges

 

[shadyJ]

Would the VTF-1 accommodate the room size I mentioned properly, if so (and if the flexibility allows it to be properly tuned), this does seem like a dead end.

I would only say that it reduce its low end if the user feels there is too much deep bass. Whether it can get louder enough for the user's taste is a matter of preference for the user. For me, I would want more output than a single VTF-1 mk3 could provide, but then again, I am crazy.

Thanks for your thoughts on Audyssey, that is pretty much my experience. I have seen it do good things with poor speakers, but with good speakers, I have less confidence it is improving the sound. In the bass; however, I feel good about what it does. The comments about the Pioneer system above are pretty intriguing!

The problem with Audyssey and frequencies above bass room modes is that Audyssey is only a workaround for a flawed speaker. The thing to do is get a speaker that has a good response on and off axis. I don't know how Pioneer's MCACC handles standing waves, but, unless something has changed recently, as far as I know MCACC does not even handle frequencies below 63 Hz. I have a Pioneer SC-55, and I prefer the sound with the MCACC off.

 

[Halon451]

Well, it's still avr based if you're talking about the Audyssey Pro kit, usually restricted to the top end avrs and it still costs extra (and is now being phased out of avrs and newer app based technology being phased in). At least I don't think there's a true stand alone kit from Audyssey....

I was talking about this:

Audyssey Pro Standalone Kit

 

[Halon451]

That gentleman also has his couch right up against his wall....in a room with challenges

Challenges galore....

 

[lovinthehd]

I was talking about this:

Audyssey Pro Standalone Kit

That's not a true standalone kit, you still need the appropriate MultEQ avr capable of working with the kit (a few XT but more the XT32 equipped ones).

 

[lovinthehd]

Challenges galore....

 

[roadwarrior]

Hope this doesn't get me yelled at too much here but Dr. Earl Geddes doesn't even really believe in room gain with regards to low frequency pressure producing devices. He states rooms in homes are too leaky for that to have any real effect.

 

[lovinthehd]

Hope this doesn't get me yelled at too much here but Dr. Earl Geddes doesn't even really believe in room gain with regards to low frequency pressure producing devices. He states rooms in homes are too leaky for that to have any real effect.

Believe in? Doesn't sound quite right, at least not without some measurements to bear that out....and then that would be dependent on room construction.