Any ideas of how to set up multiple subwoofers better

Conrad.

Moderator
@Ormy yes you're right, whenever you discover something that make either music, home cinema or both sound better it is a bit of a thrill!
If you get a brand new minidsp, plug one subwoofer input to it, connect four subwoofer outputs but don't do anything with a computer connection, does it default to just being a signal splitter/booster? I.e. no EQ or anything just sending the signal input to the 4 outputs?

Not quite. Default for the 2x4 is to act as a stereo active crossover. So input one is routed to output one and two with a low/high pass accordingly, input two is routed to output three and four in the same way.

You don't have to have the minidsp connected to the subs to be able to configure it though. So you could plug it in to the PC, connect, and then set it up in the way you've described. Then disconnect it, plug all the subs in, and leave it.
 

AndreNewman

Active Member
@Ormy yes you're right, whenever you discover something that make either music, home cinema or both sound better it is a bit of a thrill!
If you get a brand new minidsp, plug one subwoofer input to it, connect four subwoofer outputs but don't do anything with a computer connection, does it default to just being a signal splitter/booster? I.e. no EQ or anything just sending the signal input to the 4 outputs?
Sadly no.

The default config for a 2x4HD is as an active crossover with optical in, if I recall correctly. So at very least you would need to set up the routing for single sub in to all outputs, select the analog in and remove the default crossovers, 3kHz I think.

Also I found that the gain wasn't 0 using RCA.

Not much point in a DSP that mimics a Y cable or distribution amp though so you are going to need a PC, not much point in a minidsp without one.

edit: Ninja'd by Conrad.
 

Christian1975

Active Member
Nothing wrong, it's usually just better to reply where everyone can see rather than privately, that way others can help too.

You asked about the response of the Quakes compared to the Monoliths, I found a couple of measurements that show what I mean.


This is the unequalised response I get with a Monolith & Monolith+ phase adjusted (with Conrad's help) but no eq.

View attachment 1426513
This is an older equivalent measurement with the two quakes in the same locations


View attachment 1426514

The quakes have output much lower frequency than the Monoliths, ok with the Quakes the output at 10Hz to 20Hz is mostly distortion but it's ok at a low level and it's a real thing, I could hear or feel it in my ears. I don't think they would survive very long driven at high volume at those frequencies, they survived Edge of Tomorrow in my flat but as it was a flat we were listening at ~ -30dBm sometimes -25.

The Monoliths are distortion free up to much more than 85dBm but they don't have the pressure in my ears feeling ever. I debated for it seemed like forever about whether to get another Monolith or sell the one I had and get a couple of bigger sealed subs to re-create what the Quakes gave me but louder.

What decided it was a test with the Quakes where my wife told me she hated the pressure in the ears feeling from the really low LFE. I then found a Monolith+ at a nice price not too far away.

You can also see in the graphs that despite the 120Hz max setting on the crossover, the Quakes pretty much give up after 80Hz, the Monoliths carry on, they sound pretty weird and nasty with full range audio going to them but they have a go!

It's all very location dependent though, these are measurements from the two separate positions with the Quakes, they are seriously different.
View attachment 1426518View attachment 1426519

And combined after EQ, which sounds seriously improved, able to turn the volume up way more and it didn't sound unpleasant, just louder without being uncomfortable.
View attachment 1426520



Just some encouragement...

Andre

@AndreNewman out of interest, I assume based on the curves that these Quakes had the "depth" setting and not "slam". Did you do any tests with both on "slam" or with one on "slam". Would be interesting to see how they drop of then. In our bedroom setup I'm "developing", tiny speakers used, so the depth setting won't support high enough frequency. If you haven't then I may try using my mobile using a frequency sweep. I know the owner's manual quotes frequency range in both modes but we all know we can't believe that!
 

AndreNewman

Active Member
@AndreNewman out of interest, I assume based on the curves that these Quakes had the "depth" setting and not "slam". Did you do any tests with both on "slam" or with one on "slam". Would be interesting to see how they drop of then. In our bedroom setup I'm "developing", tiny speakers used, so the depth setting won't support high enough frequency. If you haven't then I may try using my mobile using a frequency sweep. I know the owner's manual quotes frequency range in both modes but we all know we can't believe that!
Hi, I did do some measurements to see what that switch did, how did you guess ;-)

In general it pushes up the response at the higher frequency end in slam mode, actually it's a bit flatter than depth, I wasn't expecting that! I'd say that depth is a bit like a house curve and slam is flat.

I finally found some graphs, they were taken at the front of my room so there's a huge dip in the middle of the response but the difference in the depth/slam switch is still very apparent.

There's two Quakes contributing but both in depth or both in slam, didn't occur to me to try one of each, I doubt that's a useful configuration unless it helps even out some room effect.

I did some other measurements when I first started with REW but it seems I wasn't very good at naming the files back then...

QuakeDepthVSlam.png


Edit: I should really add that this room has a crazy 31Hz response (length mode, lower than the bass traps can help with) so it's possible that the depth setting is flat and the slam boosts the high end... I can't find the other measurements I made a few years ago, they may have clarified things a bit.
 
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Christian1975

Active Member
Haha how did I know? Well clearly I know that you're just as much of a geek as me ;o)))
But I don't have all the tools lol... little old me uses his ears.
Well, and now Audyssey sub eq ht too haha.
Probably be more in the summer I'll be putting a lot of effort into the bedroom setup. Think I'll try slam first with Audyssey and see how it does. Concerned with some of those drops that it may not do well.
It didn't cope well when I tried it in the lounge with Quakes on depth... each set to the 75dB. Then it needed to do so much EQ that they ended up at -12dB. Can't lower their gain knob to account for how much EQ it wanted to do basically - so end up with it not achieving what it needs to. And looks like that would be not much better in slam but I can try.
It actually doesn't matter for the lounge as they're configured in a different way so don't need to achieve the higher bass, the other subs do that.
Only asked about using both as, if I can get away with it, I could stack two Quakes in the bedroom (they're pretty hidden) have one of slam and one on depth haha.
Thanks for your reply!
 

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