Electronic EQing for a sealed sub - diyAudio
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Old 1st September 2007, 05:20 PM   #1
kinser is offline kinser  Israel
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Default Electronic EQing for a sealed sub

Hi all.
After months of waiting i finnally ordered my TC Sounsd TC 2000 sub, and it arrived at my place last week. soon ill begin the construction of a 2cu. ft sealed box, using 32mm MDF and bracing te box aswell.
ill be powering the sub using two ZapPulse 2.23SE amps, one per voice coil, or bridge them for a higher load (VC's in series), they'll be running on just about 80 volts DC from a 1.5Kva transformer.

so i have the amplification sorted, i need to move on to filtering and boosting, and this is where i need help.

so my main goal is to have flat response down to 30Hz, and achive that by using LT. ill have a high pass set at about 20-25Hz, a verible low pass 60-160Hz.
But i would also like to add something else, ESP's P84, to make small corrections that the accustics in my room my cause.
My first question is can i use the LT with P84, and the second question is, in what order must each part of the filtering/EQing be? (E.g. LP->LT->HP->EQ?)

Thanks,
David Resnik
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Old 1st September 2007, 05:31 PM   #2
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Yes you can use both EQs, the order doesn't really matter. Maybe the parametric after the LT as I guess you would tend to only cut with that, so you would get better SNR that way round.

I would strongly urge you to wire the amps bridged for that level of power.

I made a sub using ZAPpulse 2.3SE and it's a great sounding amp.
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Old 1st September 2007, 05:53 PM   #3
kinser is offline kinser  Israel
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alrighty, thatnks for clearing that up! my second question now, and it is somthing that is bothering me, from the top of the basket, down till the spider, i have an opening of about 13cm width x 2.5cm High. this opening is sitting at a slight angle. now i want to use 32mm MDF, that means that these open areas will be almost blocked my the wood, only to be slightly open due to the angle of the basket, should it make a diffrence in performance? ill add a pic to show you what i am talking about.

Thanks,
David Resnik
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Old 1st September 2007, 06:20 PM   #4
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Quote:
originally posted by richie00boy

Yes you can use both EQs, the order doesn't really matter.
Depending on the desired target fc and Q, the LT can have very high amplification factor towards DC and the LT might be overloaded with a high input signal at very low frequencies.
For this reason IŽd put the HP in front of the LT.
The LP I`d place at the output to cut down noise from all the previous stages.
The order of the circuits inbetween doesn`t really matter IMO.
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Old 1st September 2007, 07:03 PM   #5
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Yes sorry I second that, I was just meaning the EQ/LT order.
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Old 1st September 2007, 08:04 PM   #6
kinser is offline kinser  Israel
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okay i see what you mean.
so it'll be something like HP-->TL-->EQ-->LP.

regarding my second post about the frame of the sub and the wood, is there anything you might have to say?

Thanks,
Kinser
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Old 1st September 2007, 08:31 PM   #7
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Quote:
regarding my second post about the frame of the sub and the wood, is there anything you might have to say?
No doubt, if the driver can "breath" through only small "slots" between driver frame and enclosure this might impair performance.

As I see it the only solution would be to make the opening in the enclosure conical. You could make it somewhat less conical where are the bars of the driver frame, respectively where are the holes for the mounting screws (I assume they are where the bars are).
Otherwise in turn You might run into the problem that You can`t tighten the srews well as there is missing "flesh" in the MDF.
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Old 1st September 2007, 08:36 PM   #8
kinser is offline kinser  Israel
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yeah i could do that, and just leave some "flesh" where the screw holes are (8 screws, 4 bars, 4 of the srews are centered at the bars, others are inbetween) wich i think might help, ill also send TC Sounds an email regarding this issue.
thank you very much for the help and info. im only 17 years old, my first high priced, real high performance sub. last one was a car sub with a diy amp, sold it for something more serious!

Thnaks,
David Resnik
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Old 1st September 2007, 08:46 PM   #9
Tachyon is offline Tachyon  Sweden
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something like this..
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Old 1st September 2007, 08:57 PM   #10
kinser is offline kinser  Israel
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yep, just not as deep, ill probbly use a router for the job.. =]
i also had in mind of using T nuts, but i wont have space to fit them in the wood..plus, the allen key hex woodscrews i got with the sub look darn nice!

Thanks,
David Resnik
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