Cross at 60 vs Cross at 100

[Acerun]

Well, this has not been my experience at all. Really the opposite. 100%.
If I might ask, why on Earth would it be true? Do you really have subs that can't play 200hrz @ 24db down from baseline cleanly?

I suppose some truly bad sub could have some crazy peaking there by where they are actually not down enough acoustically.

At any rate OP @Acerun keep your driver acoustic centers about 1/4 wavelength away or closer at the acoustic crossover frequency. (electrical means ziltch) measure the acoustic falloff.
So @80hrz the wave is about 168" so keep drivers within about 4 feet
So @ 100hrz the wave is 135" so keep the drivers within about 3feet
@ 150hrz the wave is about 90" so keep within about 2feet.

You can fudge this a little and expand the distance as there is so much bass bouncing off boundaries so soon a typical room that it is not even close to an exact science at these large wavelengths.

Plus in stereo you already have 2 or more woofers much further apart than the above yet often playing the same frequency at the same time in each L and R channel(but not mixed in stereo).

Also @Acerun remember electrical slopes are not what matters at all, acoustical slopes and acoustical summing is the key so measure and experiment with slightly different values for high and low pass. You can also try 48db slopes on the sub if you cross really high.
I often use 48 for the lowpass and 24 for the high pass when I go really high , like 150-200hrz.

Also I suggest the moving mic method averaged over a period of say 30seconds to a minute for this kind of measurement. Not single sweeps.
Also in the bass for adjustments below say 150hrz ish, use 1/12 or 1/24 octave with high Q filters. Above that 1/6 or even 1/3 is totally fine.
After granular adjustment look at the pyscoacoustic or 1/2 smoothing and see if you lost to much bass tone, if you did shelf the bass up a bit(or down if it high)

You have M126Be's. How do you cross them?

 

[jhaider]

Hypex Rhythmik 1000 watt sealed subs at $1,700 a piece aren't good enough?

I don't care who makes the amp modules or how much the finished products cost. Incidentally, the same critique (insufficient upper-bound bandwidth for many applications) applies to JL Audio Fathom, and to a lesser extent JL Audio E110/E112.

Here, the servo mechanism does (or at least did) have a deleterious impact on the upper frequency performance. See @amirm's L12 review here:

That's fine if you account for it in your system design. But a good subwoofer driver on a full-range amp should be able to play to 500Hz or so.

 

[Acerun]

I don't care who makes the amp modules or how much the finished products cost. Incidentally, the same critique (insufficient upper-bound bandwidth for many applications) applies to JL Audio Fathom, and to a lesser extent JL Audio E110/E112.

Here, the servo mechanism does (or at least did) have a deleterious impact on the upper frequency performance. See @amirm's L12 review here:

That's fine if you account for it in your system design. But a good subwoofer driver on a full-range amp should be able to play to 500Hz or so.

Is there a reason you would want it to?

 

[Acerun]

Is there a reason you would want it to?

Maybe my understanding of subwoofers are all wrong

 

[Chromatischism]

Well, this has not been my experience at all. Really the opposite. 100%.
If I might ask, why on Earth would it be true? Do you really have subs that can't play 200hrz @ 24db down from baseline cleanly?

The LFE channel carries a very wide bandwidth.

And I am speaking from experience, not from theory. The slope is not steep enough to attenuate the LFE channel below the audible range if your crossover is 100 Hz or higher.

Try it with better subs. You might change your tune.

Subs are great! Thanks.

Is there a reason you would want it to?

No.

 

[jhaider]

Is there a reason you would want it to?

If you want bass management to work as designed, the subwoofer's frequency response needs to be extend well beyond the nominal passband. (And the mains should extend decently lower than the nominal passband as well.)

 

[Tom C]

I’m not facile with this sort of thing, so please excuse my crude attempt, but what I’ve included here is a screen shot from the Rythmik L12 site. It shows that the FR bandwidth is different when using the Line In input vs. using the LFE input. Amir’s picture in his review of the L12 shows his using the Line In XLR input. The LFE input is RCA type only. I believe the thinking is that when using LFE, you’ve got an AVR doing the crossover and bass management, so there is no low-pass filter on that input, and as you can see by the graph (and as explained in the text accompanying the graph), the output of the sub is greater at 100-300Hz. The Line In inputs are intended for use without an AVR, say in a typical stereo setup, and in that case there is a low-pass filter in place, as the assumption is that you are not playing a dedicated LFE channel, but rather only integrating with the mains. So, the reason Amir’s graph shows the sub’s response rolling off above 90Hz is not because of some technical limitation of the servo design, but rather because of an optional design feature intended for a specific use case.

 

[ozzy9832001]

All right. Fresh measurements at 60,80,100, 180 (can only do 150 or 180)

For each measurement I used MultiEQ-X to set the crossover, then used REW to confirm X marks the spot for the desired crossover, then took the L+Subs measurement.

You want the one with the least variances. To my eyes, the blue line, crossed at 80hz, is the best. You can either turn up the sub or use a shelf filter to increase the bass or lower the treble.

The only time I would cross over higher than maybe 100hz is if there is some sort of weird modal issue that it would fix. Otherwise, localization will ruin the sound.

 

[Acerun]

You want the one with the least variances. To my eyes, the blue line, crossed at 80hz, is the best. You can either turn up the sub or use a shelf filter to increase the bass or lower the treble.

The only time I would cross over higher than maybe 100hz is if there is some sort of weird modal issue that it would fix. Otherwise, localization will ruin the sound.

Thanks! I believe there may be a modal issue, as 80hz sounds a bit too ripe, a touch of boom. 100hz may be the sweet spot for my room. I haven't thought of turning the subs up or down as I thought I should keep the crossover X target. I suppose I could try 80hz and turn the subs down one click? I do like having more energy coming from the mains which I hear at 60 cross and 80 cross. Then again, 100hz does sound good.

 

[Acerun]

If you want bass management to work as designed, the subwoofer's frequency response needs to be extend well beyond the nominal passband. (And the mains should extend decently lower than the nominal passband as well.)

This may or may not be related, but would love for someone to help clarify. In MultiEQ-X, in filters for Subwoofer, there is an option for "limit all" or "Limit Measured". The definition from the manual is listed below but I can't say that I completely understand it.

High Frequency Limit Mode can be selected as either ‘Limit All’ or ‘Limit Measured’. o Limit All – The filter will be flat above the High Frequency EQ Limit frequency o Limit Measured – The filter will include Target Components assigned to that channel above the High Frequency EQ Limit frequency but no EQ correction derived from measurements

 

[Acerun]

The LFE channel carries a very wide bandwidth.

And I am speaking from experience, not from theory. The slope is not steep enough to attenuate the LFE channel below the audible range if your crossover is 100 Hz or higher.


Subs are great! Thanks.

View attachment 347471

View attachment 347470

View attachment 347472


No.

I've got two of the 15" E15HP2 with the 1000-watt Hypex amplifier upgrade.

 

[HarmonicTHD]

Thanks! I believe there may be a modal issue, as 80hz sounds a bit too ripe, a touch of boom. 100hz may be the sweet spot for my room. I haven't thought of turning the subs up or down as I thought I should keep the crossover X target. I suppose I could try 80hz and turn the subs down one click? I do like having more energy coming from the mains which I hear at 60 cross and 80 cross. Then again, 100hz does sound good.

From your measurements it looks that 60Hz gives you the overall highest low frequency „power“. I would go with that and EQ down from there. Important is that as many as the nulls are filled and if 60hz does this best, then go with that. (Although it is hard to see with your Psy smoothing. Provide all the measurements with eg Var or 1/24 smoothing for better clarity which xover covers the nulls best)

 

[Acerun]

From your measurements it looks that 60Hz gives you the overall highest low frequency „power“. I would go with that and EQ down from there. Important is that as many as the nulls are filled and if 60hz does this best, then go with that. (Although it is hard to see with your Psy smoothing. Provide all the measurements with eg Var or 1/24 smoothing for better clarity which xover covers the nulls best)

Here you go! Thank you.

 

[HarmonicTHD]

Here you go! Thank you.

Yes. 60Hz it is.

 

[Acerun]

Yes. 60Hz it is.

I had previously felt that 60 had the most energy. Thank you for looking at this!

 

[jeffhenning]

A better solution for the 180Hz crossover is to turn your subs up by about 3dB and then tame that peak around 140Hz by pulling it down about 3dB with a parametric EQ.

One thing that I ran into with my subwoofers because I didn’t want to use all of the filters on the subs for home theater so I left the low end on the Rythmiks set for least group delay on the absolute low end.

This would, though, mean that certain movie effects would cause the sub(s) to clip. I got around this by just pulling the subs down 3 or 4 dB when I was watching movies. When listening to music or watching concert films, I ran them back at their normal level. No problem.

 

[Thomas_A]

Hi all,

I'm still a noob at interpreting REW measurements. I am using MultiEQ-X, a Denon X8500H, a. Purifi stereo amplifier, two Revel M126Be speakers as mains and two Rhythmik 1000w Hypex sealed subs. I took measurements of the full spectrum left channel + subs with a 60 crossover and with a 100 crossover. Can anyone help me understand if one is better than the other and if so, why?

Thank you in advance for any advice.




View attachment 347143

Are you using the speakers ported or sealed? From Erins review a sealed version would fit a typical AVR xover of 12/24 dB filter at 100 Hz or so.

Revel M126Be Bookshelf Speaker Review

Revel M126Be Review

www.erinsaudiocorner.com

 

[Acerun]

Are you using the speakers ported or sealed? From Erins review a sealed version would fit a typical AVR xover of 12/24 dB filter at 100 Hz or so.

Revel M126Be Bookshelf Speaker Review

Revel M126Be Review

www.erinsaudiocorner.com

I don't seal them. Seems like they breathe better that way. Has a more open sound to my ears.

 

[Chromatischism]

I've got two of the 15" E15HP2 with the 1000-watt Hypex amplifier upgrade.

Nice! I have the first pair of FV15HP2 produced. I plan to keep them forever. I hate changing subs.

 

[Thomas_A]

I don't seal them. Seems like they breathe better that way. Has a more open sound to my ears.

But when you cross against a subwoofer you need to match the slopes. A sealed enclosure has 12 dB/octave which will be 24 dB/octave with the standard AVR filter of 12 dB/octave. This will be matched to the AVRsub slope of 24 dB/octave. The ported response of the Revel is rather complex as you can see from measurements, not easy to match.