Well a sub mainly works in the 20-50 Hz range and even smaller rooms with 13-16,5 ft widths/lengths have their strong low nodes at 34 and 43 Hz, larger widths/lengths even lower.
Typically right up against the wall boundaries, usually not out in the room where your listening position should be.
Not to mention, most find it a lot easier to live with bass peaks in the 20 - 40 Hz range (lower the better obviously) than they do in the boomy, resonant 50 - 80 Hz range, which is also more manageable to try and tame with room treatments. Also, 20 - 40 Hz is where most loudspeakers start to roll off, so any amount of room gain (bass reinforcement) in this range would be welcomed.
1 Like
I just get into this because I did a lot of listening, measuring and tweaking in this area. While I agree with most you said about the theory and practical, my experience is, that where bass usually is welcome due to speaker roll off (20-40 Hz) the sub together with the room doesn’t at all act near flat, but while doing fine at 30 can have a crazy peak at 35 Hz etc. which then leads to lowering all the level down to a pleasant one at 35 in this example but too low elsewhere. This is where you get much more flat results with DSP/EQ. Everyone having DSP/EQ can easily try out how things would be without, but not the opposite around.
1 Like
Some high end speaker designers say high frequencies travel faster than bass notes, so they designed speakers with low frequency (bass) drivers closest to the listener, followed by midrange then tweeters. Speaking of two channel audio, would placing a subwoofer behind the speakers meddle the sound in this case? As I ask, Duntech / Dunlavy and Wilson come to mind.
With the usual flexible phase adjustment between 0 and 180 degree at the sub you can compensate for most of this influence aside of the optimal physical position for correct time alignment (which would probably be slightly in front of the main speakers).
2 Likes
Here’s my setup.
I ordered a pair of JL Audio F113’s from my dealer, who at the time told me that if I could wait a few weeks, they were coming out with an F113V2 with some significant improvements. A few weeks ago the amplifier in the sub on the right stopped working. JL Audio has a wonderful fixed price for repairing the “backplane amplifiers”, provided me with instructions on how to decouple the amp from the sub cabinet. The repaired amp arrived back home yesterday and I’m back in “bass heaven”.
Hats off to JL Audio for their excellent service!
6 Likes
The biggest thing I have is a bad taste for DSP. I’ve used DSP a few times in past iterations of my system. Every time, once it was dialed in, it sucks the life out of the music. Dynamics and impact are reduced, the airiness and “breath” is reduced, minute details are sometimes lost completely.
This is one of the many reasons why I’m pushing for room treatments instead. DSP can only do so much, and for me, the drawbacks outweigh any benefits. At least in my experiences, that’s always been the case. And this is coming from a good solid 15+ years of dealing with various medium and high end DSP units.
But hey, to each his own.
For me, I much rather go the “natural way” and dial in the system the best I can by physical means (loudspeaker/subwoofer/listening position) in the untreated room first. After that will come the room treatments, which I’m sure will require yet more tweaking of the system afterwards.
2 Likes
This has been my experience as well. Get the room right.
DSP then may make things sound better, although once the room is right who needs DSP?
1 Like
I have a dedicated room that most would consider to be thoroughly treated and use four widely spaced subs to effect modal averaging. Yet as @jazznut already observed, effective acoustical treatment of primary modal frequencies is a challenge.
And yet I still find DSP based EQ (and time alignment) applied only to the subwoofer passband, very worthwhile. Fortunately the most difficult (to passively) treat low frequency modal misbehavior, tends to largely be within the frequency range where subwoofers reign supreme. I get to have my cake and eat it too.
4 Likes
I admit I use an analog parametric EQ‘able sub, no DSP, but so far I thought in deep bass only, DSP also does no harm and is even more flexible. But I didn’t try personally.
From what I heard at shows of fully DSP‘able speakers, I’m with you, it sucks all the life and color out mostly. So I think it’s important if you speak of full range DSP, bass DSP or sub bass DSP only.
And as I said before…in case one’s able to really optimize the room also in the sub region, that’s certainly optimal (but quite rare in most homes I guess).
2 Likes
Thank you JN
I have around 16 cm between one of my main-speakers backside and my sub and my DSPeaker Anti-Mode 8033C makes wonders for my sub.
1 Like
Not behind, but 7" forward of the left monitor! Monitors are HP/powered sub is LP at 50Hz, with time alignment of all transducers. Bass is tight, fast and deep, with great punch and accurate tonality and musical transients! Overall, soundstage presentation is very deep, very wide, very high and Very holographic as speakers totally disappear!! 
Ted
5 Likes
Hey there @Theo et al,
A little someting to keep in mind if you are obsessing about perfect time alignment with your subwoofer install. Almost all modern active subwoofers implement their adjustable crossovers and phase adjustment in DSP. The digital conversion cycle and DSP associated with this will create several milliseconds of signal latency at a minimum.
If your subwoofer(s) offers built in automated DSP room EQ like those of JL Audio, Martin Logan, & Paradigm, the latency will increase further to 3-4 milliseconds or even higher. If you were truly obsessed about perfect time alignment (which doesn’t seem necessary to achieve a seamless transition in my experience), for each millisecond of latency, you would actually need to move the subwoofer ahead of the mains by 1 foot.
3 Likes
MTBV,
Thanks for your input and comments!
FWIW, my HP/LP selected 50 Hz x-over is active via my line level pre-amp outputs to my power amps. My sub is 17 years old and believe it has no DSP circuitry that I know of (nothing in the manual states that).
After several hours of room placement trial & error, the best sweet spot listening for the sub’s very low bass response is the location it is at in the picture! My assumption that driver time alignment may relate to that success might not be completely accurate, but this is what my ears and my acoustical music (especially pipe organ) tells me!!
Ted
A big thank you!