JBL M2 Audiolense Digital Crossovers w/Subs

[FrantzM]

If This forum didn't exist ... One would have to invent it .. Wow!!

I will audition this set-up ... very soon. Am thinking of it as an end game kind of set-up for 2 channel.. Total BOM looks like under $30K.. Re-WOW!!

 

[dallasjustice]

If This forum isn't exist ... One would have to invent it .. Wow!!

I will audition this set-up ... very soon. Am thinking of it as an end game kind of set-up for 2 channel.. Total BOM looks like under $30K.. Re-WOW!!

@FrantzM You are welcome anytime. @RayDunzl will be here too next week, maybe.

 

[Wombat]

Calculator: http://tripp.com.au/sbir.htm

 

[amirm]

Calculator: http://tripp.com.au/sbir.htm

Pretty nifty. Hadn't seen that before.

 

[Thomas savage]

I think we should all decend on @dallasjustice , I declare his listening room the destination for the inaugural ASR rave.

 

[hvbias]

I was planning to do something similar with flanking subwoofers on either end of the main tower speakers (mandatory in my case since the mid/upper bass horn doesn't extend as far as a ported box), briefly had a discussion of this with @Bjorn at the Klipsch forum.

What I'm trying to figure out is what Audiolense would do better than Acourate (or vice versa). I couldn't find anything searching Acourate's group and it would be in poor taste to ask about a competing product on their forum.

The digital crossovers is my primary interest, with the falling response of the K-402 I doubt I would be using "room correction" with a target, but never say never until I've actually heard it.

 

[Olli]

Calculator: http://tripp.com.au/sbir.htm

@Wombat : I don't exactly understand how this calculator would help me determine if 1) more subs would help eliminating room modes and 2) where I would need to cross them. BTW, I am using Audiolense with a virtual 2 way set up, a 3 way compact speaker that is on top of two subs, crossing over at 98 Hz. Here's the room dimensions and the calculated values:

 

[andreasmaaan]

@Wombat : I don't exactly understand how this calculator would help me determine if 1) more subs would help eliminating room modes and 2) where I would need to cross them. BTW, I am using Audiolense with a virtual 2 way set up, a 3 way compact speaker that is on top of two subs, crossing over at 98 Hz. Here's the room dimensions and the calculated values:

View attachment 26891

You're right, this calculator doesn't help you much here.

What it does tell you is (assuming the walls are perfect reflectors at all frequencies, which in reality they are not) where your first reflections will create peaks and nulls in the frequency response; however, even in its ability to do this is there significant limitation, because (1) the drivers are all at different heights and (2) the nulls will really also depend on the location of your ears in relation to the acoustical centre(s) of the driver(s).

One thing I can tell you, without knowing much about your room, is that moving the subs so that they are in more optimal locations in the room is likely to better eliminate (reduce) room modes.

Harman did extensive modelling to try to solve this problem, and then tested the models in real rooms, and concluded that the optimal locations for two subs were halfway along any two parallel walls. So basically like this:

Depending on the quirks of your room, however, YMMV.

Also, getting the crossover to work correctly will be more work than in the relatively straightforward configuration you have atm with them direcly under your mains.

Do you have a measurement microphone?

 

[Olli]

You're right, this calculator doesn't help you much here.

What it does tell you is (assuming the walls are perfect reflectors at all frequencies, which in reality they are not) where your first reflections will create peaks and nulls in the frequency response; however, even in its ability to do this is there significant limitation, because (1) the drivers are all at different heights and (2) the nulls will really also depend on the location of your ears in relation to the acoustical centre(s) of the driver(s).

One thing I can tell you, without knowing much about your room, is that moving the subs so that they are in more optimal locations in the room is likely to better eliminate (reduce) room modes.

Harman did extensive modelling to try to solve this problem, and then tested the models in real rooms, and concluded that the optimal locations for two subs were halfway along any two parallel walls. So basically like this:

View attachment 26892

Depending on the quirks of your room, however, YMMV.

Also, getting the crossover to work correctly will be more work than in the relatively straightforward configuration you have atm with them direcly under your mains.

Do you have a measurement microphone?

Thanks @andreasmaaan - yes, I do.

Unfortunately I can’t place them much differently (wife). I could however add 2 subs at the back wall - a 4 sub array. I was thinking about putting the current subs there and getting 2 Rythmik F8s below the compacts instead.

 

[andreasmaaan]

Thanks @andreasmaaan - yes, I do.

Unfortunately I can’t place them much differently (wife). I could however add 2 subs at the back wall - a 4 sub array. I was thinking about putting the current subs there and getting 2 Rythmik F8s below the compacts instead.

Could you post some measurements from at and around the listening position(s)?

 

[Olli]

Sure:

 

[RayDunzl]

Sure:

View attachment 26897

Looks like you're in pretty good shape, to me.

Insert a similar dip to the one at 48hz at 70Hz... see if you can hear it.

If not, I wouldn't spend too much on the other one.

 

[andreasmaaan]

Sure:

View attachment 26897

Doesn’t appear to be much wrong with that, depending I guess on how the measurement(s) was taken etc.

What do you believe is lacking?

 

[Olli]

Thanks guys. Nothing‘s lacking... More the other way around. I just get too much bass with certain tracks compared to my other set ups. I had a similar experience in another room where adding a 2nd cheap sub diagonally behind me (almost) eliminated the problem. That's why I thought 2 (or 1) more sub(s) at the rear wall could improve this.

Here's L and R solo - something must be wrong with the R measurement though (drop at high FQ), can't re-measure at the moment.

 

[andreasmaaan]

Thanks guys. Nothing‘s lacking... More the other way around. I just get too much bass with certain tracks compared to my other set ups. I had a similar experience in another room where adding a 2nd cheap sub diagonally behind me (almost) eliminated the problem. That's why I thought 2 (or 1) more sub(s) at the rear wall could improve this.

Here's L and R solo - something must be wrong with the R measurement though (drop at high FQ), can't re-measure at the moment.

View attachment 26898

I can’t recall if you said already how you were implementing your bass management, but the measurements suggest the best thing to do in this case would simply be to tone the bass down by a couple of dB if it seems too much.

My only other questions would be: where are these measurements taken from? Are they averages of multiple measurements? And how do things look in the time domain?

If just a single measurement for each channel at one location, they may not be telling the whole story.

 

[Olli]

Looks like you're in pretty good shape, to me.

Insert a similar dip to the one at 48hz at 70Hz... see if you can hear it.

If not, I wouldn't spend too much on the other one.

You mean with a parametric eq?

 

[RayDunzl]

You mean with a parametric eq?

With whatever tool you have at hand...

PS: I typically measure left/right/and both, since I don't usually listen to just one side or the other...

 

[Olli]

First measurement I posted is LR together , the other one is single L and R measurements, with a single sweep.

 

[Olli]

I can’t recall if you said already how you were implementing your bass management, but the measurements suggest the best thing to do in this case would simply be to tone the bass down by a couple of dB if it seems too much.

My only other questions would be: where are these measurements taken from? Are they averages of multiple measurements? And how do things look in the time domain?

If just a single measurement for each channel at one location, they may not be telling the whole story.

It is a single measurement with a sweep at my listening position. Bass MGMT is with Audiolense using Roon’s convolver. The sub crosses over to the mains at 98 Hz.
Let me check the time domain.

How would you recommend to measure things more meaningful?

 

[Olli]

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