room gain?

[davygrvy]

point 3 is good. I had a conversation with a friend regarding the use of four subs in each corner. If one used an all-pass network (phase shift with respect to frequency) separately on the rears, it should be possible to steer any room modes outside of the sweet spot. In other words, the rears would be used to act as cancellations to some room behavior.

The idea sounds like fun to try, though my living room at home is sub-optimal due to it being open to the kitchen on the left side.

[planet10]

Both Toole & Geddes go into it a lot deeper with Toole having had the benefit of Harmans big bucks to conduct extensive research. The chapter on taming room nodes is worth the price of addmission all by itself.

dave

[SY]

One problem is the approximation of room boundaries as rigid.

SYclotron Audio » Biamping the NHT M3.3, part 3

Take a look at the graph near the bottom of the page.

[Cyan]

Originally Posted by planet10

2/ 1st reflections are to be preserved (and their FR as close to the direct radiation as possible)
3/ you need at least 2 subwoofers and they should be mono.

dave

Nice ones. The second is very strange (but won't ask you to explain, as i guess it's a very long explanation.
About the third, i think it's not necessair for them to be mono. A guys who works in this field told me that for the most recording techniques (if not all), the bass are practically mono. So there should be no real need to set them mono.

[planet10]

Originally Posted by Cyan

The second is very strange (but won't ask you to explain, as i guess it's a very long explanation).

Short version is that outside of the recording studio studies have shown that having the 1st reflection is preferrable.

dave

[Cyan]

Originally Posted by planet10

Short version is that outside of the recording studio studies have shown that having the 1st reflection is preferrable.

dave

So you say that first reflections are bad while creating music (recording studio), and that they are fine while reproducing music?

[markus76]

Originally Posted by Cyan

So you say that first reflections are bad while creating music (recording studio), and that they are fine while reproducing music?

Toole's recommendation is not a radical new concept. The only major difference is treatement of the first lateral reflections. He says it's beneficial for stereo and optional for multichannel.
If you don't want to read his book then you'll find his basic statements here:
http://harman.com/EN-US/OurCompany/T...ions/13686.pdf

Here's a more detailed description of a "Toole room":
Olive Munich AES Presentation on Harman Reference Room

Best, Markus

[ruferto]

I have the same problem with 50....60hz gain, my question is, is it better to build a large helmholtz resonator bass trap or several small ones?
sorry for the dumb question

[markus76]

Originally Posted by ruferto

I have the same problem with 50....60hz gain, my question is, is it better to build a large helmholtz resonator bass trap or several small ones?
sorry for the dumb question

First you should find out what the problem really is by measuring the in room response. If it turns out to be a modal peak, then it's probably easier to use an EQ.

Best, Markus

[davygrvy]

pardon... room mode problems should not be fixed with an EQ. Fix the room.