Axiom Home Page Forums General Discussion Home Theater Setting up my subwoofer

Mojo you should consider another 2 or 4 ep500. I’ve been reading / watching videos about subwoofer line arrays. REL is the obvious name that comes up with sub line array but I don’t see why ep500 couldn’t be used. The sub array is an interesting concept in a 2 channel setup.

Plus I know you like stacking things that are axiom.

I guess i should say it’s a bit more complex then just stacking them. The way I understand it is each tier manages a separate section of the bass frequencies. The floor tier the lowest frequencies , mid tier mid bass , and the top tier is supposed to be de coupled from floor entirely for the intangibles and room feel in the air, so to speak.

So I guess just stacking them is not going work without spe cialized mounting and crossover control.

Could this be managed in an active setup with specific frequency response with dsp control for a 3 sub bass line array added to the lfr1100? With left and right systems in an active individually amplified 3 unit bass line array this would be a RADICAL way to finish off an active lfr1100 system.

Ok Ian, get to it!!! Mojo is waiting to stack em!

The Captivator only goes to 16Hz anechoically. Paradigm is the only one I know of that can go to 12Hz. Apparently it can do 8Hz. It's also 13 grand!

Kodiak, the 500s don't help. They're "only" good to 18Hz. Adding 500s increases SPL and, depending on placement, can spatially flatten response but cannot reach lower.

What you are suggesting about sub arrays could work. Heck, you could have one 600 for each Hertz between 10 and 80 Hz. LOL!

The short answer is I'm happy. I'll eventually do some measurements ... but ... it will have to wait till I get back into the audio mode.

I currently have two 600s set up off the active DSP place just inside the LFRs (like your 500s)
The other two are set up on the side walls and are being driven by the AV8805's sub outs. I haven't really played with optimizing placement as I have a lot of construction material in the way (and moving them around is a pain). Plus, level wise I'm not sure If I set them up perfectly ...

With the LFR subs I measured the SPL at the listening position and raise the sub volume till I noticed a change. On the side subs I played white noise and set the volume of each side sub to measure the same. Then using the receiver's control raised and lowered the both side subs playing together to hit the same SPL as the fronts. After which I checked the levels by ear to see if they were far off ... kind of hard to tell in most cases.

I'm thinking of redoing the DSP sub levels by manually generating some frequency sweeps (say from 100hz on down). Now I can play the LFRs and set the sub levels to best fill in the LFRs low end ... what do you think?

You may have a better way of doing this ...

Good to know about the 600s.

I don't know what the correct way is of setting up multiple subs. I'll try to summarize what I did. I used logic but I'm not sure if my logic is logical. It sounds good. Maybe it can sound better if I was Trevor.

The essence of this is that I set up each active and its 500 individually so that they both sum equally to 73dBC at my MLP. The reason for 73dBC is that I sometimes use the "double-bass" setting on my Onk. This routes the left and right channel bass to my 800. That gives a nice boost at my MLP.

A. Preliminary steps

1. Dedicate the 800 to the .1 channel

2. Turn off the 800

3. Set the actives to full range

4. Set each 500 to 40Hz.

5. Set both 500 gain knobs to half-way

B. 500 phase adjustment

1. Turn on the left active and 500. Ensure the right 500 is off.

2. Play a 40Hz tone. Vary the left 500's phase knob until the SPL peaks at the MLP. I could have used a friend's help with this but I didn't want to skew the response so I used binoculars. LOL!

3. Shut off the left active and 500 and turn on the right active and 500. Repeat step 6 with the right active and 500.

C. 500 gain adjustment

1. Shut off the right active and the right sub

2. Play pink noise. Set the left 500 to 70dBC at MLP. Turn off the left active and 500.

3. Play pink noise. Turn on the right active and 500. Set the right 500 to 70dBC at MLP.

4. Turn on the left active and 500. Play pink noise. Measure the combined SPL from both actives and 500s at MLP. If not 73 dBC, incrementally adjust each 500 to reach 73dBC.

D. 800 phase adjustment

1. Turn on the actives, the 500s and the 800. Set the 800's gain knob to 1/4 way.

2. Play pink noise. Vary the 800's phase knob until the SPL peaks at the MLP.

E. 800 gain adjustment

1. Shut off the actives and 500s

2. Play pink noise. Set the 800 to 75dBC at MLP.

Well don’t know about the phase stuff ... I just kept mine at 0
But if you set the subs to be the same volume as the fronts ... your boosting the base (which given my hearing might not be a bad thing).

I‘m thinking that maybe a way to match the sub Level to the LFR is to
1. meter at the MLP, set the DSP crossover out of the way and play a 100hz tone with the subs level set at 0.
2. Now start raising the sub level till you see a change in SPLs at the MLP
3. Back off the sub level so it drops to the original LFR alone level.
4. Set the DSP crossover to 40 or what ever you think is right.

Think that works for match the subs off the DSP. For the subs off the receiver/processor I’d set them to the same level relative to each other, then repeat the same sort of thing raising the pair to match the LFR

Phase is important. All drivers have to be in phase alignment otherwise they are working against each other.

Each active and 500 pair is gain-adjusted simultaneously. See step B1.

Your way of adjusting would work with a 40Hz tone if that's where the cross-over to the LFRs is.

I’d have to think a bit about phase as how the pressures add is dependent on frequency and location.

Yes. Phase response is a function of frequency and position. It can never be perfectly compensated.