Should I use 1x15" or 2x12" Genelec subwoofers?

[napfkuchen]

I don't understand why you're using this combination of speakers and subwoofer at all. In my small room (4 x 3.6 m), the 8331A-7350A combo is already more than sufficient and delivers a frequency response of +/- 1,5 dB between 20 and 100 Hz with only a single 8 dB dip (40-43 Hz). I also tried other (not very practical) locations and eventually achieved a measurement where the dip was gone. However, I didn't notice the measurable improvement in everyday use. For that, it would probably require an upgrade for the human ear. So I switched back to the more convenient placement.

Nevertheless, I would also recommend the DiracART solution and multiple subwoofers based on my own experience (with Audyssey, GLM and regular DiracLive). For me, that's why I now much prefer listening to music in the living room now.
Perhaps you also have the option of placing absorbers at least at the first reflection points to reduce early reflections?

 

[Mort]

I don't understand why you're using this combination of speakers and subwoofer at all.

Likely because you don't play this at 90db. I still get the system to red light at 95db on that track and similar content. It really depends on the music to which one listens.

based on my own experience (with Audyssey, GLM and regular DiracLive).

You do or don't have Dirac Art and GLM? So far, I have not found anyone that actually is using both and can compare.

Perhaps you also have the option of placing absorbers at least at the first reflection points

Does that work for a null below 100hz? Reportedly it's ineffective but I could be wrong. Either way, it's not a dedicated listening room so it's unlikely I could get large bass traps in there. I do keep thinking about it.

 

[Mort]

1) Fixed a bug in GLM
2) used REW room sim to estimate a 50hz crossover, lower than the 85 I was using.
3) Allowed GLM to configure the speakers individually.

Looks better.... not flat of course but better.

 

[napfkuchen]

Likely because you don't play this at 90db. I still get the system to red light at 95db on that track and similar content. It really depends on the music to which one listens.

Not my type of music and preferred listening volume (usually 75-80 dbSPL in GLM), but tried it anyway. GLM set to -33 dB is enough for 90 dB output, but at about 92-93 dB the 7350a goes red. At this moment my ears were already bleeding, couldn't listen to such loud music for more than a few minutes.
But somehow I can't logically understand wanting to listen to music so loudly on the one hand, and then being bothered by a slight dip in the frequency response on the other. My room is already dampened with many absorbers (some 40 cm deep), but at this volume you can definitely tell that room modes are "having a party".

You do or don't have Dirac Art and GLM? So far, I have not found anyone that actually is using both and can compare.

Unfortunately both systems are in different rooms. My experience is that in the larger room with DiracART the individual sound sources are much more clearly separated from each other than with the Genelec setup, regardless of the positive GRADE report. And with Dirac it's very easy to individually tweak the target curves. Only the center in my DiracArt-setup is a Genelec speaker (8351b) and fits in fine. Imho, if you want more precise bass in the listening position, ART with several subwoofers is the way to go.
Then again, seeing your latest post, why bother? There will still be some small room problems but your system should be very capable. Perhaps think less about how you can improve the setup and listen more to music. It's like with my other hobby (simracing). 500 hours, 10 for racing and the rest for system tweaks.

Does that work for a null below 100hz?

No, definetely not. But perhaps stereo separation will be clearer then.

 

[Mort]

But somehow I can't logically understand wanting to listen to music so loudly on the one hand, and then being bothered by a slight dip in the frequency response on the other.

Noted. Thanks for sharing.

why bother?

Because it's there. I mean, why do anything? It's a goal like any other.

Perhaps think less about how you can improve the setup and listen more to music.

And that's just patronizing.

 

[Exprymer]

The propper acoustical answer would be to have two 12 units, because not only they have more Sd, they, when positioned correctly, help create a wavefront that is more planar, therefore reducing the impacts of some modes of the room.

 

[Kain]

Likely because you don't play this at 90db. I still get the system to red light at 95db on that track and similar content. It really depends on the music to which one listens.

When you stated you can get the system to red light at 95 dB on that track, are you referring to the 7380A subwoofer or the 8361A speakers? Or do they all/both red light at 95 dB?

 

[Mort]

I could still do the 2x7370a 12". And I might but it feels silly since a) I don't need anything but smoother bass and b) sub crawling and RoomSim have not revealed any options for a second sub that will flatten my bass in this tiny square room. Doesn't mean it's impossible but I have not had luck yet. A few options:

1. Dirac Art might help, but I don't want to give up EPL. But if I can figure out how to keep the Genelecs running in full range mode with EPL, they each have massive bass capacity for ART to dynamically manage. One sub plus two full range mains should be enough. More would be better though.
2. The other option is to confirm if GLM truly craps the bed when subwoofers are different sizes (as I was told on support.) I'm just surprised in a proprietary system that different subs don't work together. Different monitors work together with extended phase linearity, why not subs? I would put together my 15" and a 12". Could still go with DiracArt still.
3. Option 3 is to use all three and see if I can overwhelm the it with just GLM.
   

I'm waiting on Genelec support to answer #1 and #2.

 

[Mort]

When you stated you can get the system to red light at 95 dB on that track, are you referring to the 7380A subwoofer or the 8361A speakers? Or do they all/both red light at 95 dB?

Using bass heavy tracks measured DB-C, I can get the compression lights to come on one device at 985db, but it varies. Over 100 and they would all be on.

 

[Mort]

Room sim slightly flattens rhe response with three subs vs one but that doesn't look hugely better to me.
Still maybe it's enough to fix my 'problem.'

 

[darth]

Fwiw, when asking some questions about altitude ci, trinnov rep told me to not even bother with GLM. Let wave optimizer do its thing.

Our recommendation with the Genelec speakers is to bypass GLM and let the Altitude perform all of the speaker and room correction.

 

[Mort]

Fwiw, when asking some questions about altitude ci, trinnov rep told me to not even bother with GLM. Let wave optimizer do its thing.

I know but I don't think I want to give up EPL though.

 

[Trdat]

Does that work for a null below 100hz? Reportedly it's ineffective but I could be wrong. Either way, it's not a dedicated listening room so it's unlikely I could get large bass traps in there. I do keep thinking about it.

I wouldn't recommend at first reflection points rather doing some research to find out where exactly the SBIR or room mode is coming from then adding the bass trap at that point, that would help by how much I don't know.

And regarding would it help a null below 100hz, well would adding at reflection points help definitely not but adding at the point from where the null is created from ceiling, side walls, opposite side walls etc yes it could as long as the bass trap is thick enough.

 

[Trdat]

I've experimented a lot with what your trying to achieve and adding subs only marginally helps with filling out room nulls, of course this is from my basic experimentation. However, adding a second sub provides a fuller sound which I think is an awesome upgrade regardless if it fills out nulls or not.

Whether or not you can have two different subs, at least for me that is based on how tight you want the bass and the timing. I have two different systems one with 4 subs with the timing slightly off for a bouncier bass while my second system has stereo subs with perfect timing that provides a punchier tighter more controlled bass. Even then, I highly doubt there will be an audible difference but two different sized subs is just weird.

 

[dagfinn]

I could still do the 2x7370a 12". And I might but it feels silly since a) I don't need anything but smoother bass and b) sub crawling and RoomSim have not revealed any options for a second sub that will flatten my bass in this tiny square room. Doesn't mean it's impossible but I have not had luck yet. A few options:

1. Dirac Art might help, but I don't want to give up EPL. But if I can figure out how to keep the Genelecs running in full range mode with EPL, they each have massive bass capacity for ART to dynamically manage. One sub plus two full range mains should be enough. More would be better though.
2. The other option is to confirm if GLM truly craps the bed when subwoofers are different sizes (as I was told on support.) I'm just surprised in a proprietary system that different subs don't work together. Different monitors work together with extended phase linearity, why not subs? I would put together my 15" and a 12". Could still go with DiracArt still.
3. Option 3 is to use all three and see if I can overwhelm the it with just GLM.

I'm waiting on Genelec support to answer #1 and #2.

I would try the 7370/80 combo, since it'll cost you nothing and tell you a lot. I run my 7360a/7370a combo in analog mode, I use miniDSP Flex for crossing to my analog mains, and for EQ. Two bass sources sounds and feels different, more enveloping - I'm sure you'll like it. Also, I run stereo, there is so much music literally killed by summing to mono. Very bad! Not sure if GLM can do stereo subs?

If you're red lighting all the time, maybe you gear is undersized? It's a big move, so I'd try stereo subs first.

Rosewood is custom, stands by ATC .

 

[Ilkka Rissanen]

@Ilkka Rissanen A question if you have time. Are you able to confirm that GLM has drawbacks when using different sized subwoofers? What happens if I mix a 7380a and a 7370a in a small room? Genelec support said it was discouraged because they are 'tuned differently'. That never sounded right to me, but I am not an expert.

GLM does not have any drawbacks when using different sized subwoofers, it always treats and calibrates each subwoofer as individual and separate units, it does not 'see' the other subwoofers in the system nor do they affect the calibration result. The drawback comes from general acoustics and physics. As 7370 and 7380 have slightly different LF extension and frequency response at the low end corner ('tuned differently' refers to Helmholz frequency, often called 'tuning' frequency), they also have slightly different phase response there. It you want to achieve perfect addition of two LF sources, they need to have identical phase response as well as frequency response. Extreme example is two subwoofers with the other's polarity flipped 180 degrees. Frequency responses would still look identical when measured separately but when measured together, phase/polarity difference would cause a massive cancellation.

This is the reason why our customer support did not recommend to have different sized subwoofers in the same system. In many cases they can work but we don't want to encourage customers to use such unconventional setup. Of course in reality the phase difference between 7370 and 7380 is very small and only near the LF corner. And in real listening space, the room modes will also affect the phase response, especially if the subwoofers are no co-located, making the phase summation more complex, even with two identical subwoofers.

A bigger problem in my mind comes from the fact that you are trying to sum two devices with different maximum output capabilities. The smaller and less capable 7370 will always be playing about 6 dB closer to its output limit, and if/when reaching the limit, it will start to compress and clip while the 7380 still has another 6 dB to go - a huge difference! You might as well have two 7370s instead for a more balanced subwoofer setup.

 

[Ilkka Rissanen]

Not sure if GLM can do stereo subs?

GLM does not care if the subwoofers are configured as mono or stereo. It is all about how the actual signal cables are routed to them. If you connect only left channel to left subwoofer and right channel to right subwoofer, you will have stereo subwoofers. If you route both channels to both subwoofers, you will have mono subwoofers.

 

[audiofooled]

Room sim slightly flattens rhe response with three subs vs one but that doesn't look hugely better to me.
Still maybe it's enough to fix my 'problem.'

View attachment 507019

Should you decide to go for 2 subs option, IMO this kind of setup could make sense:

It's a combination of 1/4 and 1/3 (quarters and thirds) boundary distance that would still retain viable listening triangle and give least individual response shape aberrations for any of the bass sources at selected mic positions. You are then hopefully left with only the peaks to be taken care of, dips should be no more.

You can try it in the room sim yourself and see that the response shape should stay the same for most gain settings and crossover points. Of course I would suggest running subs in stereo.