Subwoofers and Phase Question For You Sub Experts


I use a pair of Dunlavy SC-3 speakers, known for their time/phase coherent crossover design.

When the stars align the speakers completely disappear and there’s a sense of space and 3 dimensionality that I’ve heard from few other speakers/systems. It’s easy to destroy the illusion with things like poor placement, poor setup of room treatments, etc.

Adding subs to the setup is both a blessing and a curse. The Dunlavy’s need some support in the nether regions and a pair of HSU subs do add a solid foundation to music which enhances the overall presentation; however, it’s at the expense of some stage depth, width and image dimensionality. Placing the subs a few inches forward of the front plane of the speakers helps a little but that isn’t where they perform at their best as ‘subwoofers’.
Finding optimal room positions for bass augmentation always creates a clash with the phase aspect of integration resulting in the diminished soundstage described above.
Playing with phase settings has little impact on the problem since there’s just a toggle for 0 and 180.

Which brings me to the questions - 
1/ How does running a swarm setup, with 4 subs, affect phase/time integration with the mains? Does it create twice or half the issue or remove it altogether?

2/ Looking at subs such as the JL Audio F series with auto room calibration, does the EQ algorithm compensate for any time/phase anomaly or is it simply looking for a more linear bass response?

I don’t mind investing in more sophisticated subs so long as I don’t end up with the same problem. I’m not really inclined to mess with software and the like, unless there’s no other way.

Thanks

Rooze


128x128rooze

Showing 15 responses by erik_squires

OP, if you think this is a phase problem, in the sense that you would hear out of phase L and R speakers, swap both of your main speaker cables.  See if that fixes what you are hearing.
If that's not it, then I have no idea why we are talking about phase problems in your particular situation. If that's not what you are hearing, then the issue is the usual complicated subwoofer problem of integrating to the room and main speakers.
Auto EQ is soooo variable.  

It is damn convenient and anyone can ise them, but I can understand why many dislike the results.  So, Dirac and JL have good results.

I love my miniDSP but what a PITA to set up right
Um, the speed of sound in air at ground level is generally given to be approximately 1,200 feet per second.


https://en.wikipedia.org/wiki/Speed_of_sound

1 millisecond = 1/1000 of a second, so 1.2 feet per millisecond or 14.5".


So 1/10 of a millisecond would be about 1.45"
I go back to one thing.

I recommend the OP turn to GIK acoustics first. Ask them for advice on room and then see where he's at.

Best,
E
Kenjit,
To paraphrase your post in another thread:
I refuse to engage with you unless you can prove to me it would be worth my time.




Hey Kenjit:

which if i recall correctly has been heavily ridiculed by the experts on diyaudio.

Post your link. Like any other project, plenty of discussions.

By the way Kenjit, unlike you, I’ve posted my entire design. You keep asking me questions about it, and claim your own are far superior, with zero data to back them up.

Here's the discussion on the SNR-1

https://www.diyaudio.com/forums/multi-way/316511-snr-1-mundorf-scanspeak-2-a.html


Kenjit,
It's also your ability to hold simultaneously opposite positions on a subject matter which we all remember. 
PS - I don't have a problem with swarms.  Just their cost, placement, wiring, etc.

The physics are fine, but from a convenience point of view, 1 sub with bass traps and EQ rules.
No one has to rely on my expertise alone.

I've posted a number of references, and agree with Duke.

The physics don't change.  I just happen to have experience with it, and shared the way.


Best,
Erik
Kenjit,
It was your grandiose claims and lack of ability to alter your reality as more information was presented which contradicted your claims.



EQ is a lame idea, DSP or otherwise. But no more lame than taking advice from a bunch of guys with absolutely zero idea what they’re talking about. Which is every single post so far!



Hello @millercarbon,

We have gotten to the unfortunate part of a discussion where you assert knowledge of your own little in evidence and denigrate that of others leaving me no choice but to out you.

I used to work in motion picture equipment industry, including design, installation and set up of some of the best sounding motion picture audio gear in the world. I also make my own loudspeakers and do my own room EQ.

My views are pretty much the same as those posted by JL Audio, though as I posted elsewhere, I disagree with them in some nuanced ways:

https://forum.audiogon.com/discussions/me-vs-jl-audio-an-open-discussion?highlight=me%2Bvs%2Bjl%2Bau...

The problem you’re having rooze, and the mistake you’re making, is the same one I made and everyone makes and that’s following the conventional wisdom, because the conventional wisdom is WRONG! The conventional wisdom is based on the idea that because sound is waves and bass is waves then bass must be the same as midrange and treble. When its not.

That’s not the conventional wisdom, and not what I’ve seen anyone propose. The general solution, as written by and accepted by professional acousticians and installers, for getting deep bass in a room with moderate spend is bass traps + EQ.


http://ethanwiner.com/basstrap_myths.htm


My views and recommendations are also largely in line with what GIK Acoustics would recommend, so please, contact them directly and ask.

https://www.gikacoustics.com/

If you have lots of room, time and money, get more subs, and a custom room. Otherwise, I stand by my advice of using a DSP based solution along with appropriate room treatment and question your judgement and qualifications.

Best,

Erik
Um, what you haven't convinced me of, at all, is that your problem is "phase" related.
It's the entire integration of the subwoofer to speaker and room. That's what you are describing.

Adding a mini DSP correctly will allow you to perfectly blend in the sub to your speakers (yes, including phase) as well as blend it to your room. Better with bass traps that can help drain the energy out of persistent room modes, but still effective without.
Hey Rooze,

If you use your subwoofer in a review environment, you should use miniDSP.  What I'd suggest is you do it for the subwoofer alone.  This lets you leave every other part of your chain undisturbed.

Best,

E
Personally, whenever I have heard Hsu's, they do not have much in the way of definition...and as such tend to deliver bass heft, but not bass resolution. ( which is great for HT, but not so much for our audio systems).



It's all in the EQ in front of them. :)

Hi Rooze,

I know swarms and more subs are the popular thing, but I dono't think that's the first direction.


I have a Hsu and I love it, but integration is key. The issues you have described may not be phase related at all.

Do you have any bass traps?  Consider adding those to your room. Talk to GIK Acoustics.


Yes, JL audio's room EQ is awesome, but also, you can do the same with your current subs and a miniDSP HD unit.  Either will, with the help of bass traps, fix your issues. The problem is the learning and implementation.  If you have the money, and don't want to go down a rabbit hole, get the JL subs. If you have the time, and want to learn, miniDSP with Room EQ Wizard is your most cost effective and just as good solution. 


I mean it when I say this, JL Audio won't be a better sounding solution than what you have now, but it sure will be faster. :)