Do I have my IB subs set up incorrectly? - AVS Forum
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post #1 of 14 Old 11-08-2012, 11:06 PM - Thread Starter
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I've been having a gigantic issue with getting any sound from my subs. Here's my other thread on it from the Amp forum:
http://www.avsforum.com/t/1436209/no-sub-signal-from-a800-to-behringer-ep2000

I originally thought it was the amp/receiver, and it still may be, but I'd like to rule out some more basic things now.

Setup is 4 AE IB15s, 8 ohms. Going to an EP-2000 amp. I'm trying to do two subs to each channel, because I don't need a TON of power.

Let's start with the wiring. It is my understanding that to wire them in parallel, I need to do red to red, black to black, and then on one sub, a black and a red wire to the neg/pos terminals on one channel of the amp.

CCE3823C-4966-4BE7-8FE4-DE49C7545EF0-8288-000009AC986B4DCA.jpg
D21CF950-A58D-46F6-9AAF-072E11C93C6E-8288-000009AC9C6B0E06.jpg

I've wired both sets of subs up this way, one to each channel, with the low cut filter set to OFF and the rest of the amp jump switches where they need to be for parallel mode as opposed to bridge mode.

If this wiring is correct, is there a problem with the physical set up of the subs?
13E8F760-CF3D-454C-AE56-B1B5904438D5-8288-000009AC9FEAF5E6.jpg

They are located in a closet directly behind my theater room. The idea is that the openings on the boxes will vent into the room, but I don't want to cut the walls out and mount up the subs until I know that everything is working correctly and I won't have to change the boxes around.

I feel really stupid and incompetent right now, as well as completely frustrated.
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post #2 of 14 Old 11-08-2012, 11:34 PM
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have you checked the dc resistance through each driver and the overall system?

Listen. It's All Good.
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post #3 of 14 Old 11-09-2012, 12:01 AM
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Wiring seems correct.

Connecting your manifold to baffle (wall) should help. Now sound is attenuated because lack of separating drivers front and back waves, those cancel each other.

If you plan to test manifolds positions before cutting holes to wall, you need to use some other subs or make some temporary enclosures for the job.
Normally blocked manifold can be used as test box, but your is probably too small for the job. Two simple closed box with one driver should be fine.

If its front wall, 1/4 and 3/4 along wall would be good points to start testing. In theory that should eliminate width modes between side walls, so you get same output to all seats in front or back row.
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post #4 of 14 Old 11-09-2012, 12:42 AM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

have you checked the dc resistance through each driver and the overall system?

I know how to check resistance for each driver (which I will do shortly), but I'm not sure what you mean by testing the whole system or how I would go about doing such a thing.
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Originally Posted by Ile View Post

Wiring seems correct.
Connecting your manifold to baffle (wall) should help. Now sound is attenuated because lack of separating drivers front and back waves, those cancel each other.
If you plan to test manifolds positions before cutting holes to wall, you need to use some other subs or make some temporary enclosures for the job.
Normally blocked manifold can be used as test box, but your is probably too small for the job. Two simple closed box with one driver should be fine.
If its front wall, 1/4 and 3/4 along wall would be good points to start testing. In theory that should eliminate width modes between side walls, so you get same output to all seats in front or back row.

I'm not overly concerned with the positioning of the subs so much as just having them produce sound at this point.

I also don't understand what you mean by two closed boxes with one driver to test them. Do you have a diagram of what you are describing? Thanks!
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post #5 of 14 Old 11-09-2012, 01:03 AM
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Quote:
Originally Posted by Silock View Post

I'm not overly concerned with the positioning of the subs so much as just having them produce sound at this point.
Manifold with one open side won't produce bass before you install those to wall, wall will separate drivers front and back waves.
Back space work as a enclosure.

It's same when you try to get bass from sub driver in your hand, not working. It need enclosure or least big baffle...
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Originally Posted by Silock View Post

I also don't understand what you mean by two closed boxes with one driver to test them. Do you have a diagram of what you are describing? Thanks!
That was just idea for testing subs locations before you cut holes to wall.

With bigger manifold you can just block open side with temporary plate and use that for testing position, but your manifold is so small that it probably wont work pretty well.
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post #6 of 14 Old 11-09-2012, 01:31 AM - Thread Starter
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I see what you're saying now. Blocking the open side may not work well, but will it work AT ALL? Otherwise, I really have no option but to go ahead and cut the wall and mount the boxes up.
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post #7 of 14 Old 11-09-2012, 02:06 AM
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From the information in your other thread it seems to me that your receiver is not outputting a high enough signal. This seems to be a common problem with people using pro amps and receivers. Some information is mentioned in this thread: http://www.avsforum.com/t/1395368/who-here-is-going-straight-from-receiver-pre-outs-to-a-pro-amp-for-their-subwoofer/0_100

Typically a booster device is used inbetween the AVR sub out and the pro amp. Most people use the mini-dsp as you also get the ability to EQ the signal as you like.

I've never used one of these devices so take my advice with a grain of salt till someone else confirms it. If you want to double check you can try sending a signal to the subs using a different audio device than the receiver. Something like an mp3 player with some bass tones on it would work if you get the right adapter.
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post #8 of 14 Old 11-09-2012, 02:49 AM
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Quote:
Originally Posted by Silock View Post

Blocking the open side may not work well, but will it work AT ALL?

Not very well. 2 AE driver in about 20 liter closed box peaks 10db at 110Hz and there is lack of bass.

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post #9 of 14 Old 11-09-2012, 06:15 AM
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You can try using a DMM to check what kind of voltage your receiver outputs when using a subwoofer test signal. IIRC, the EP2000 needs ~1.2V input to output full power. I have a Yamaha RX-V665 and that can drive my EP4000 to full power without a signal booster so I would expect your A800 should also be able to.

I seem to recall someone saying that their Monoprice RCA-XLR cable was miswired and caused similar problems.
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post #10 of 14 Old 11-09-2012, 07:09 AM
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You are running the subs in free air. You won't get any sound out of them this way like Ile mentioned earlier. However, you should still get excursion. I would try connecting 1 driver at a time to test and make sure each driver is working with a 20 Hz sine wave. If you are playing music through two subs, as mentioned in the other thread, you will hardly get any excursion since the frequencies aren't low enough. I have 8 AE IB15 drivers in my infinite baffle and hardly feel any driver movement with music even with the volume turned way and tons of output coming from the subs.
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post #11 of 14 Old 11-09-2012, 09:08 AM
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Quote:
Originally Posted by desertdome View Post

I would try connecting 1 driver at a time to test and make sure each driver is working with a 20 Hz sine wave.

+1 but also you mentioned that you may have a problem with you receiver. Can you take that out of the equation by either using another receiver or simply hooking up an iPod to the amp? The other thing to consider is that the sub out on you receiver may need a boosted signal going to the amp. If that's the case then you would need a pre-amp running in-between the receiver and the amp. I run one of these in my system.

I don't remember if you mentioned the brand and model of your receiver or not, sorry.

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post #12 of 14 Old 11-09-2012, 10:29 PM - Thread Starter
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Update:

Alright, I used the DMM to verify that the subs are all hooked up correctly. When not wired together, each displays 8 ohms of resistance, and when it's all wired, they read 4 ohms.

Edit: I never could get any kind of reading from the RCA cables wrt to voltage. My DMM always read zero when I was testing the cables, and did so with 2 different sets. I'm either an idiot or something is broken. I was about to throw in the towel and decided to just hook it all up with the Monoprice RCA->XLR cables I have and do the test tone.

So, I used a 20 Hz test tone signal from YouTube and wouldn't ya know, I got a serious signal light on the Behringer. This is the result at -30.0 dB:
https://www.youtube.com/watch?v=mxexWr-aPKE

Is the only problem now just the placement of the subs in the room to separate the waves and get some bass going? If so, I just realized I may have created myself another dilemma.

The subs are going to be placed in a long closet behind the AV room. There's a cutout in the wall that houses the AV rack. Is that going to create the same problem as I have right now with them just sitting in the closet, unattached to the wall? Or will I be okay because of the physical presence of the wall?

Rack:
3C6F25F5-1A0D-4DD0-8984-B7E5A13FB6BB-9360-00000B40F103D092.jpg

Closet:
D32F37B1-B732-4F51-91A8-8E0320675C26-9360-00000B40F73CC5D8.jpg

There's another 10 feet to the closet behind where I took the picture. It's very long, and I could put both boxes down at the end of the closet very far away from the door and the cutout for the AV rack, but it would be in the back corner of the room, and I'm not sure that's a very good place for them.
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post #13 of 14 Old 11-10-2012, 04:54 PM
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Check the drivers with a battery. Both drivers should move inward or outward depending on the terminal you touch. If one driver moves inward and the other outward, they will nullify each other.

I would question if those manifolds have enough flow area for best results. Ideally you want an area equal or greater than that of the combined drivers. Having less can result in something more like a band-pass subwoofer.
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post #14 of 14 Old 11-12-2012, 01:33 AM
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Quote:
Originally Posted by Silock View Post

There's a cutout in the wall that houses the AV rack. Is that going to create the same problem as I have right now with them just sitting in the closet, unattached to the wall? Or will I be okay because of the physical presence of the wall?

Yes it will have bass cancelation near AV rack, hard to say how big that area will be without testing. If you don't have measuring equipments to test, it would be safest to block that rack hole. Wall with door to that long closet would help.

I agree, bigger manifold opening would be better. Again it's hard to say if it will be problem or not.
Minimum opening would be around 15" x 10", if you use same principle (15"/3 x2 ) that down firing subs distance from floor.
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