[Kw6]

Hey guys,

I want to even out the bass in my one subwoofer setup. My Nad amplifier streamer c390dd has sub 1 & 2 outputs for stereo subwoofer mode. I mainly use for two channel music. My question is for the second sub do you need exactly same brand, type and size woofer as the first sub? Thanks!

[artur9]

According to Geddes, no.

Geddes specifically recommends multiple and different (not matching) subs to force more randomness (and I assume averaging) of room modes

from https://www.diyaudio.com/community/threads/multiple-small-subs-geddes-approach.134568/
Integrating subwoofers and mains using the Geddes method can take hours.  I think it took me 6h the first few times I did it.
IMO, using the same kind of subwoofer is probably a good idea in terms of sealed and ported.

Hence, for ease of integration, probably.

[Kw6]

Ok thanks! I will check out the link!

[artur9]

What I found is that I could get a pretty good frequency response even without any DSP, which was kind of cool.

[Kw6]

Nice!

[jtcf]

I have two different brands - 2 HSUs (ported) and one SVS (sealed).It wasn't hard to set them up. The crossovers are all set just above where the bass rolls off,all set at the same Q,but the volume is different on each. If I was going to start over I would go with the SVS all the way around because the app lets you adjust everything from the listening chair.No going back and forth to tweak them.

[JLM]

Check out Duke LeJeune's swarm.  It follows Floyd Toole's theory for evening out inherent in-room bass peaks/dips and uses 4 small subs.  I use three, as per Earl Geddes, one sealed 10" and two ported 10" of different brands to good effect.

[richidoo]

If you're using the subs in stereo, in front next to main speakers for stereo bass then yes better to be the same for matching tone. Below 80Hz you wont notice stereo bass but if you have very high end subs that can play cleanly up into mid bass and you adjust speaker crossovers to use mid bass from sub then stereo position is better so you can hear stereo mid bass information. But if using subs in distributed bass arrangement to achieve flattest room response below 80Hz then different subs are recommended just to further randomize and flatten the in-room response.

[Thomas02]

Thanks for this information. Really useful.

[andysuandthecats]

sub is just a box speaker able to go low and crossover filter is , well i guess what is called sub bass and two of the same is best and can be cheap doesn't have to cost thousands few hundred cheap on ebay is good enough nothing wrong with second hand used , or diy

but mix subs with other subs is doable and one at front and one at back of room evens the bass out and cheap behringer DCX 2496 is must have then can add 6 subs with single LFE.1 input or use two inputs A left stereo sub and C right stereo sub , use B for LFE.1 per , channels outputs 1 2 3 4 5 6 and use nine peq filter bands with maybe cheap behringer FBQ 2496 daisy chained channel A to channel B so to maximum the peq bands to 40 should be enough to smooth the frequency response , with some trail and error as it would take while     

behringer class d amplifiers nx3000d 6000d series which seem to be popular 

it can be done cheaply