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  Topic Review (Newest First)
01-24-07 12:05 AM
Josuah
Re: Sealed Sonotube Subwoofer

Now that REW 4.0 has been released, I can post the <10Hz measurements I took of these subwoofers. I'm running two LP shelf filters to boost low, and about a dozen PEQs IIRC. I used Sonny's ECM8000 calibration mic and extrapolated to -12dB at 5Hz. Here's the graph.
12-05-06 05:10 PM
Chrisbee
Re: Sealed Sonotube Subwoofer

Your response curve would be even more flattering using the forum's preferred axes limits.
Stretching to 10Hz is quite acceptable for those with something to show in this area.

12-04-06 12:27 AM
Josuah
Re: Sealed Sonotube Subwoofer

I'm using the new digital Radio Shack SPL meter with the correct calibration file loaded. Also my soundcard response loaded. You can see the two lines on the graph. I'm leaning towards the 11.5Hz being a peak, rather than the 10Hz being a null.
12-03-06 09:25 PM
Exocer
Re: Sealed Sonotube Subwoofer

Good question Bruce. I assumed the answer to that was a yes.
12-03-06 05:48 PM
brucek
Re: Sealed Sonotube Subwoofer

Quote:
Here is the response graph I've got so far
What sound meter or mic are you using? Are you using the correct calibration file?

brucek
12-03-06 03:14 PM
Exocer
Re: Sealed Sonotube Subwoofer

Awesome response! Job well done.

I wouldn't worry about much of anything else at this point,unless for some odd reason you're not satisfied with what you hear...
12-03-06 03:05 PM
Josuah
Re: Sealed Sonotube Subwoofer

I've got the clip limiters turned on on the EP2500. And I've been watching the lights on the DCX2496. So far, they've never gone above the second bar. Right now I've got a 28dB boost going using a pair of LP shelf filters each set at +14dB. It's chained as follows:

pre -> input 1 -> output 1 -> input 2 -> output 2 -> EP2500

Inputs 1 and 2 are linked with regards to their DSP settings.

Here is the response graph I've got so far, after applying about 11 EQ filters somewhat manually and somewhat suggested by Room EQ Wizard. But I'm not sure what's right yet because the 10Hz drop could be either a null or just represent issues at 11Hz that needs to be cut (unfortunately no outboard hardware EQ has 11Hz filters that I'm aware of). I'm going to need the newer Room EQ Wizard to know.
11-28-06 09:50 PM
---k---
Re: Sealed Sonotube Subwoofer

Ah, you're putting two drivers in each tube? That makes more sense, and sounds about right for a Qtc=0.7 (Though I probably would have shot for an even lower Qtc). I saw two tubes, so I thought you were giving each driver your 5cuft.

Additionally, my Behringer DEQ2496 only allows a max boost of +12. And yes, lots of power required.
11-28-06 09:31 PM
soho54
Re: Sealed Sonotube Subwoofer

EP 2500 output power (1 kHz, 0.1&#37; THD) per channel stereo: 500 watts RMS @ 8 ohms, 750 watts RMS @ 4 ohms, 1,200 watts @ 2 ohms. Output power (1 kHz, 0.1% THD) bridged mono: 1,500 watts RMS @ 8 ohms, 2,400 watts RMS @ 4 ohms.

You are aware of the incredible amount of power required to boost 10hz 18db, right? Be careful or you will clip your way into new drivers, fast.

Lets say you are cruising around with explosions going off around 60hz loud enough to eat up 25w. To play any 10hz content at the same level will require 1800w. At 50w nominal we are up to 3500w for 10hz. Umm... 100w at 60hz is 7000w at 10hz.

Just a reminder not to go boost crazy. Keep the boost level in mind and you will be fine. Have you checked out the FRDs LT spreadsheet?
11-28-06 06:36 PM
Josuah
Re: Sealed Sonotube Subwoofer

Is it because I put two drivers in the 5 ft^3?
This thread has more than 10 replies. Click here to review the whole thread.

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