46607
From: Anders, [0x5e91ff25.adsl.cybercity.dk]
Subject: DIY ATC C4 sub
URL: http://www.atcloudspeakers.co.uk/downloads/driver_specifications_sb.xl.zip
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I have been looking at the ATC C4 sub with their 12" bas unit and digital amp. I currently have the active SCM50's and a Tact RCS mini 2.2, which feature a configurable LP filter and gain/phase control. As the C4 sub is very expensive and I don't need all the controls due to the abilities of the Tact I thought of building my own with the same driver coupled directly to a similar specified amp as the original (650W/8ohm). As far as I know the C4 is a closed design with the measures of 582x500x500mm with build in amp. Doing the calculations with the drive unit data and a Qtc of 0,7 gives a volume of only 40 liters. A Qtc of 0,5 gives 95 liters, which would match the outer dimension of the box better. Can this really be true or am I on the wrong track here? Driver specs can be seen in the link. Thanks Anders Moderated By: brian@diysubwoofers.org |
46608
From: andrewt, [host86-169-101-57.range86-169.btcentralplus.com]
Subject: Re: DIY ATC C4 sub
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Hi, do you have the T/S parameters for the driver? A Qtc = 0.5 is unusually low for a sealed sub. Have you used the sealed driver calculations in this Forum? |
46609
From: Anders, [1053ob.scansafe.net]
Subject: Re: DIY ATC C4 sub
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Yes I used the excel sheet. Here are the parameters: Fs=23 Hz Qms=1.5 Qes=0.3 Vas= 245 litres Cms= 6.3 Mms= 73 grams Rms= 7 N.s/m Resistance nominal= 5.4 ohms Impedance nominal= 8 ohms Max tracel= 25 mm Diaphragm effective area= 550 cm2 Nominal power rating= 75 W Maximum input power= 150 W Maximum power program= 300 W Moderated By: brian@diysubwoofers.org |
Responses:
[46610]
46610
From: andrewt, [host86-160-42-37.range86-160.btcentralplus.com]
Subject: Re: DIY ATC C4 sub
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download WINisd pro. input your data and your amp power. see all the displays as graphs. Very good software. It will also show just how little bass extension there is in a sealed box. Download Linkwitz transform design and read up on LF equalisation and Q adjustment. I recommend a Maximum of 10dB of LF gain to maintain good sound quality. Many use between 15dB and 18dB of LF gain. Be very careful with power going this EQ route. You can burn out the VC very easily or run out of Xmech and damage the driver. |
Responses:
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