Re Audio sxx 12 paired with behinger epx3000 HELP (1 Viewer)

[Marcus Harry]

I'm looking to build a home theater subwoofer. I have a Re Audio sxx 12 dual 2 ohm subwoofer, currently being used in my car but that will soon change. I just ordered a Behinger epx 3000 amplifier. It will be placed in a large living room. Re Audio recommends tuning to 2.0@33Hz in a ported box.

I'm looking at wiring it bridged @ 4ohm.

I could use advice on the entire project from the box to wiring. I would like to keep the box rather simple.

 

[Tom Vodhanel]

I'm looking to build a home theater subwoofer. I have a Re Audio sxx 12 dual 2 ohm subwoofer, currently being used in my car but that will soon change. I just ordered a Behinger epx 3000 amplifier. It will be placed in a large living room. Re Audio recommends tuning to 2.0@33Hz in a ported box.

I'm looking at wiring it bridged @ 4ohm.

I could use advice on the entire project from the box to wiring. I would like to keep the box rather simple.

You will want to go larger and tune lower. I'm guessing those are recommendations for car/truck use?

I haven't looked at the t/s(post them here and others will help with the enclosure). but I'd guess something in the 3.5 cu-ft range tuned to 21-24hz might work well. Also, the amp is capable of 3000w? You might want to wire it for just one channel(900w) initially.

3000w +no HP(subsonic filter) = the potential for bad things to happen.

Tom V.

 

[Robert_J]

Electrical Q Value -Qes: 0.49Mechanical Q Value -Qms: 4.5Total Speaker Q Value -Qts: 0.44Free Air Resonance -Fs: 25.1 HzEquivalent Compliance -Vas: 72.9 litersOne-Way, Linear Excursion -Xmax: 18 mmEfficiency -SPL 1W/1m: 86.1 dB SPLEffective Piston Area -Sd: 480 cm^2DC Resistance -Re: 2.8 ohmNominal Impedance -Znom: Dual 2/4 ohmThermal Power Handling -Pe: 600 WForce Factor -Bl: 17.7

 

[Marcus Harry]

SXX 12" T/S Parameters:

[*]Electrical Q Value (Qes): 0.32
[*]Mechanical Q Value (Qms): 4.4
[*]Total Speaker Q Value (Qts): 0.30
[*]Free Air Resonance (Fs): 30.6 Hz
[*]Equivalent Compliance (Vas): 47.6 liters
[*]One-Way, Linear Excursion (Xmax): 22 mm
[*]Efficiency (SPL 1W/1m): 88.1 dB SPL
[*]Effective Piston Area (Sd): 480 cm2
[*]DC Resistance (Re): 1.9 ohm
[*]Nominal Impedance (Znom): Dual 2 ohm
[*]Thermal Power Handling (Pe): 1000 W
[*]Force Factor (Bl): 21
[/list]

 

[Marcus Harry]

I am also assuming that those recommendations are for vehicles. I've done a little research on the amplifier and people have been saying the more realistic wattage is around 1900 watts. The woofer is rated at 2000 peak. So maybe If I do bridge I will keep the gains(proper lingo?) down and ease into turning it up.

Also on that note, the amplifier will get signal from my Sony receiver subwoofer out via RCA cables. The amp does have rca's but I've heard an unbalanced signal may not be good. Any easy/affordable ways around this??

-Marcus

 

[Marcus Harry]

Wrong speaker looks like the srx possibly
Thanks though Robert

Electrical Q Value -Qes: 0.49Mechanical Q Value -Qms: 4.5Total Speaker Q Value -Qts: 0.44Free Air Resonance -Fs: 25.1 HzEquivalent Compliance -Vas: 72.9 litersOne-Way, Linear Excursion -Xmax: 18 mmEfficiency -SPL 1W/1m: 86.1 dB SPLEffective Piston Area -Sd: 480 cm^2DC Resistance -Re: 2.8 ohmNominal Impedance -Znom: Dual 2/4 ohmThermal Power Handling -Pe: 600 WForce Factor -Bl: 17.7

 

[Robert_J]

I did grab the wrong ones.

I am also assuming that those recommendations are for vehicles.

Vehicles and music as the material. Unless you are one of those guys playing the Decaf songs, then you aren't really hitting the lows. Home theater has the lows especially if you like action movies. There's a lot of sub 20hz material and some movies get into the single digits. There's a small group of guys who have a goal to reproduce those sounds at reference levels.

I've done a little research on the amplifier and people have been saying the more realistic wattage is around 1900 watts. The woofer is rated at 2000 peak. So maybe If I do bridge I will keep the gains(proper lingo?) down and ease into turning it up.

RMS and peak wattage ratings are almost useless in home theater applications. Those ratings are thermal. Just look at the next to last line of the specifications. That means it can take 1000w for a specified period of time before things start to melt. In home theater, we model a sub in the proprosed enclosure and look at the mechanical limits. Let's say you are cranking some techno music with some good 40hz bass and your subs are moving 10mm each direction. You switch to a movie and want to watch it at the same volume. To get the same SPL at 20hz, your sub will now have to move 40mm in each direction. (To get the same SPL at an octave lower, the excursion quadruples) That will destroy your sub by crashing the coil into the back plate or ripping the spiders as the coil shoots out of the gap.

Also on that note, the amplifier will get signal from my Sony receiver subwoofer out via RCA cables. The amp does have rca's but I've heard an unbalanced signal may not be good. Any easy/affordable ways around this??

I use a cable from Radio Shack. One end has an RCA which is plugged into my Pioneer receiver's LFE/Sub output. The other end has a 1/4" mono phono plug and is connnected to my Behringer Feedback Destroyer. 1/4" mono plugs connect my BFD to my Behringer EP-2500 amp. Speaker cables connect my amp to a pair of 15" TC-3000 subs, each wired for 2 ohms and installed in 3.5 cubic foot sealed enclosures. The BFD flattens the in-room response to + or - 3db from 100hz to 15hz.

 

[Marcus Harry]

Looks like I will be wiring it to one channel then. I know the disadvantage of have a 12 vs 15 is the low's but I'm just working with what I got. Can you any recommendation for a box size and hz? I would like to go ported.

The feedback destroyers looks a little expensive. Would you say it's necessary?

 

[schan1269]

$100 is expensive?

 

[Marcus Harry]

Not seeing them for $100 not sure if you can give me a link to where your finding that price? I should say it seems like a high price for a simple operation of high pass filter/hum destroyer/balanced signal.

Also coming from a college student budget..

$100 is expensive?

 

[schan1269]

1124There are a couple on Ebay. One has three days and with shipping(to me) is $80...There is one with no bids(free shipping) for $125.

 

[Marcus Harry]

I think I'm going to get the Behringer DI100 for $33. The amplifier's built in low pass filter + preamp out should get rid of any high frequencies. Now I just need to get a better idea of box size and what to tune it to.

 

[Robert_J]

I know the disadvantage of have a 12 vs 15 is the low's

Not really. It's final SPL. Bass is about moving air and when comparing two subs with the same excursion, a 15" has about 50% more piston area (the Sd parameter) than a 12". An 18" has about 50% more Sd than a 15" and a 21" has a little less than 50% more Sd than an 18". Right now, 21's are the biggest that have any decent quality. Mach 5 has some on pre-order and Incriminator keeps them in stock. I have one from Exodus Audio that I picked up for a steal during their going out of business sale.

The feedback destroyers looks a little expensive. Would you say it's necessary?

I did not buy one until I measured my sub's in-room response. I knew I would have a peak around 55hz caused by the voice coil inductance but it ended up being a 14db peak. It made for a really boomy sound. The BFD pulled down the peak and I boosted the very low end a few db and that's it. It made an incredible difference.

I think I'm going to get the Behringer DI100 for $33. The amplifier's built in low pass filter + preamp out should get rid of any high frequencies.

Your receiver's crossover will get rid of the high frequencies. If you go ported, you want to get rid of the low frequencies below your enclosure's tuning frequency. If you had gone with the Brehringer INUKE DSP series amps, they include a high pass filter as well as a parametric EQ similar to the BFD all in one nice package.