Subwoofer level question. When to boost subwoofer output for dips?

[Chris A]

Generally, I don't recommend miniDSP at all nowadays to the guys that I help dial-in their systems remotely. I would recommend Xilica or something with a lot more capability and a little less "Dirac capability". Having the Dirac stuff integrated into the preamp having much greater total gain and lower noise floor seems to be a much better approach.

Personally, I gave up on "room correction software". It brings more problems than it seems to solve. I guess those individuals that don't have much understanding of the domain...well...I guess that Dirac is about the only way that they can apparently get better hi-fi "at the push of a button only".

YMMV.

Chris

 

[Ultrasonic]

I guess that Dirac is about the only way that they can apparently get better hi-fi "at the push of a button only".

Hmmm... to be honest I think where many people seem to go wrong with Dirac Live is they think it's essentially an automated single process rather than the interactuve tool it actually is. Requiring experimentation and adjustment to taste from the user. Which is not to say it's flawless in the slightest!

I'll be honest I've never heard of Xilica. I'll look them up some time.

 

[Chris A]

Hmmm... to be honest I think where many people seem to go wrong with Dirac Live is they think it's essentially an automated single process rather than the interactuve tool it actually is. Requiring experimentation and adjustment to taste from the user. Which is not to say it's flawless in the slightest!

If you want freeware, even open source FIR-type solutions that apparently even do time domain corrections (i.e., "Gunness focusing"'), those can easily be substituted. I know a couple of guys that have been using CamillaDSP (apparently the predecessor app for DecayCore) and swear by its performance--even on low-cost gear (Raspberry PI, etc.). Dirac isn't really on my radar--to be honest. I'll just say that there are probably other, more capable, freeware FIR/IIR software and hardware implementations available if the user is willing to go down the type of "interactive" path you're implying.

I'll be honest I've never heard of Xilica. I'll look them up some time.

Xilica is a Canadian manufacturer. That should lower the price to those living in the UK (i.e., Commonwealth duties). I think their current mainstream product is the Solaro series. I'm told their performance tops their older XP/XD series processors, and the plug-in modules can be added to increase the number of channels handled. They also handle Dante environments (if that appeals to anyone here).

I've been using a Xilica XP processor since 2015. Danley Sound Labs (DSL) has been using Xilica XP/XD for a much longer time and apparently re-brands them as their own stenciled processors.

Chris

 

[Ultrasonic]

If you want freeware, even open source FIR-type solutions that apparently even do time domain corrections (i.e., "Gunness focusing"'), those can easily be substituted. I know a couple of guys that have been using CamillaDSP (apparently the predecessor app for DecayCore) and swear by its performance--even on low-cost gear (Raspberry PI, etc.). Dirac isn't really on my radar--to be honest. I'll just say that there are probably other, more capable, freeware FIR/IIR software and hardware implementations available if the user is willing to go down the type of "interactive" path you're implying.

For context I only ended up trying Dirac as a byproduct of buying a miniDSP SHD for other reasons and it just came with it. I'd previously used a miniDSP 2x4 HD and was used to doing things manually and so didn't think I needed it. Which to be honest I don't but it does make things quicker/easier, especially in terms of working with data averaged over multiple measurement points (which I do think it a good idea now). Whilst it does require user input this is at the level of dragging sliders/points to adjust the target curve and the frequency range it is applied over, so whilst it is interactive it's significantly more accessible that the options you've mentioned above I think.

Sometimes you'll see people saying they tried Dirac Live and didn't like it but had literally just gone through the measurement process once, and then listened to the result with the default target curve. So for example complaining that there is too much/little bass but not attempted to adjust the bass level (which is trivial to do). People that do this come into it with the mindset that it's an automated process and the default must be "correct". This is why I commented as I did above and I do see this as a somewhat common misconception/problem.

I'm no sort of Dirac champion though as I don't like it for anything other than bass correction, although some like it full-range. This may be room/system dependent to a degree.

Edit: oh, and if/how much the time domain correction elements of Dirac Live may actually be audible/beneficial I'm not at all sure. This is never a reason I'd encourage anyone to use it.

 

[Chris A]

Sometimes you'll see people saying they tried Dirac Live and didn't like it but had literally just gone through the measurement process once

I spent several days of trying to get Dirac to pass the basic "pass through" test of doing nothing to the output--taking literally hundreds of upsweeps, even using widely varying measurement positions around the prime listening position. It never passed that test and always produced an unusable output. (It did apparently use some sort of FIR flattening of the phase, but the phase correction was far too mild to have audible improvement.) It always failed around the 100-300 Hz band, and gave the user an impression that it could make ±0.1 dB flatness amplitude spectra.

Chris

 

[Oddball]

No, I wasn't talking about distortion on bass output of subwoofers or loudspeakers. Rather considering the peaks and troughs in the bass response caused by room modes to be distortion compared to the smooth bass response we'd want. This is clearly audible, and much more so than let's say the difference between 1 kHz SINAD of 80 dB vs 90 dB (totally hypothetical numbers but you get the idea).

Sure. Traditional distortion for subs is still audible if out of control, especially before it gets to transition belt of 20-30hz. Even great subs get to 25% THD or more at the end of their reach.

Otherwise, yeah, there is a whole minefield out there. FQ response, decay, phase response, distortion graphs, etc. But there are ways to manage at least some of them. It's not just as easy as cutting and boosting.

 

[Chris A]

Edit: oh, and if/how much the time domain correction elements of Dirac Live may actually be audible/beneficial I'm not at all sure. This is never a reason I'd encourage anyone to use it

Really?

 

[Ultrasonic]

I spent several days of trying to get Dirac to pass the basic "pass through" test of doing nothing to the output--taking literally hundreds of upsweeps, even using widely varying measurement positions around the prime listening position. It never passed that test and always produced an unusable output. (It did apparently use some sort of FIR flattening of the phase, but the phase correction was far too mild to have audible improvement.) It always failed around the 100-300 Hz band, and gave the user an impression that it could make ±0.1 dB flatness amplitude spectra.

Nobody uses Dirac Live with the intention of making no change at all though, and at the point you are making changes then it comes down to the relative significance of the positives vs the negative you're describing here. As above, I feel for most this will be a clear win overall and as such I don't take it potentially not being able to do absolutely nothing as a dealbreaker.

Also note it's filter design has regularly been changed, so depending quite how long ago you tried your test it may be different now. Or indeed not.

 

[Ultrasonic]

Sure. Traditional distortion for subs is still audible if out of control, especially before it gets to transition belt of 20-30hz. Even great subs get to 25% THD or more at the end of their reach.

Otherwise, yeah, there is a whole minefield out there. FQ response, decay, phase response, distortion graphs, etc. But there are ways to manage at least some of them. It's not just as easy as cutting and boosting.

Sorry but you're still missing my point. It has NOTHING to do with subwoofer distortion.

 

[Ultrasonic]

Really?

Not quite sure what I'm meant to be taking from that post?

 

[Chris A]

Nobody uses Dirac Live with the intention of making no change at all though, and at the point you are making changes then it comes down to the relative significance of the positives vs the negative you're describing here.

Then you can forget everything that I said in my responses and be happy with what you've got. Clearly, Dirac's good enough for your use.

Chris

 

[Oddball]

Sorry but you're still missing my point. It has NOTHING to do with subwoofer distortion.

I suggest you just read my post. It is all in there and no need to be antagonistic. I think all the members are trying to help you.

 

[Ultrasonic]

Then you can forget everything that I said in my responses and be happy with what you've got. Clearly, Dirac's good enough for your use.

Did you post the testing you're referring to here? I'd be interested in a link if you did. I'm assuming we're talking VERY small differences but I'd be interested to see.

 

[Ultrasonic]

I suggest you just read my post. It is all in there and no need to be antagonistic. I think all the members are trying to help you.

I'm only posting to help too .

 

[Oddball]

I'm only posting to help too .

You know how they say in the airplane - help yourself before you help others.

 

[krabapple]

Usually what occurs in-room is that you're taking measurements at the listening position (LP) or around the LP(s)--and then trying to boost room null positions.

That only thing that I've found that actually works, no matter how much "headroom" that you think you've got with the sub(s), is to add another low frequency source in another wall location--either another full-range loudspeaker or sub at the "antinode" room position on centerline between the left/right walls or between the front and rear walls to fill up the room's null mode positions as much as is possible. This is an effective method of dealing with a room null. But only so much can be filled using this approach,, especially if your LP is at a double or triple null room position.

Smoothing a room null mode then becomes a matter of working with the room's exact geometry and size--not amplifier or subwoofer power. Once you add another channel of low frequency output, you'll find this out for yourself.

It's like you've actually got two rooms that you're trying to fill up with low frequency output, It's very room and listening position-geometry specific.

Chris

For width modes this comes in handy --courtesy of Floyd Toole. And it qualifies as a 'how-to". (The strategy of course also works if used on other room axes)

see also: https://www.avsforum.com/threads/multiple-subwoofers-cannot-even-out-nulls.3316039/post-63710900

 

[ShadowBoxer]

have been using CamillaDSP (apparently the predecessor app for DecayCore)

DelayCore (formerly CamillaFIR) is an auto-optimizing FIR creator leaveraging the CamillaDSP package (both by different authors).

DelayCore was renamed to avoid confusion between the two distinct tools (such as what happened here). DelayCore doesn't deprecate CamillaDSP - it optionally complements it.

 

[Ultrasonic]

You know how they say in the airplane - help yourself before you help others.

Wow. That's an absurd characterisation given my contributions to this thread addressing the OP's actual question. Any misunderstandings/apparent disagreements are largely off-topic and of much less significance.

 

[Torin Krell]

Yes, this is exactly what I've done.



Whilst this idea is appealing (and I did this myself years ago for this reason) I'd say it's not generally a good idea for two reasons.

1. Whether you increase sub level and attenuate, or leave it where it is and boost more, if the resultant frequency response is the same then the subwoofer is outputting exactly the same thing. So it's not somehow being pushed less hard to reduce the dip in the frequency response if that makes any sense?
2. To optimise the transition from main speakers to subwoofer you want them to be level matched at the crossover frequency. That way above the crossover frequency the main speakers will dominate and below the crossover he subwoofer will. If instead the subwoofer is at a significantly higher level at the crossover frequency, it will still dominate for a range of frequencies above the crossover frequency and you're more likely to run into problems with the sub being localisable. And just the whole transition being less seamless.

If you like the sound of what you have then that's great but you may find you can improve on it slightly if you wanted. Maybe something to consider if you have an urge to experiment some time.

Thank you for your feedback Ultrasonic! I actually applied something similar to your recommended approach first, however in my room I found my ultimately chosen second approach needed less PEQ correction overall (2 bands, just a few decibels attenuation) and resulted in a smoother Harman curve. I believe what makes my chosen approach work is that the overall sub boost is slight, changing the "centerline" between boost and cut just enough, and the subtle PEQ cuts also proved to retain sub / main balance. Comparing both approaches, my second approach also required less overall maximum decibels of boost at low frequencies - retaining more sub headroom. It seems that attenuating a couple of subtle response peaks (second chosen approach) was more effective in my room than trying to boost a few nulls (first approach). Perhaps this is simply a case where the best approach simply depends on the specific room response and gear used. Also in my room, sub position was very carefully optimized first (hours of iteration) to minimize the need for significant PEQ correction.

 

[Digital_Thor]

I can't seem to find the info, but what speakers are the OP using?
Does he have to matching subwoofers just next to his mains, extending their lowest frequencies, or are they scattered around the room aiming for maximum overall smoothness?

Accepting the lowest output unit you have, meaning finding the "weakest" link - might be a good starting point, when tuning a system
In my system, the 2 woofers in each main tower, is the lowest output of the entire system. So when adjusting levels, I have to accept that everything else has to be lowered to match the output capabilities of my chosen woofers. So matching the mains with my subwoofers, kinda only require me to lower the output of my subwoofers, once I found the smoothest transition between all bass sources - in my case with MSO, wide overlap and all closed boxes for minimum phase trickery.