SPL box for an SQ setup?
09-06-2004, 09:53 AM
#1
I've been pondering lately... I do a lot of pondering in my spare time.
Since I am planning ot use my IDmax as an IB subwoofer, and since Iasca has an SPL portion to it's scoring, I got to thinking about box design.
so here's my theory, I want to know if it'll hold water, or leak like a sieve.
If I built a box, tuned to say 70 Hz, give or take, but a purpose built SPL box, and then ran my sub for SQ, lowpassed @ 60 Hz or so, with the midbass highpassed at 75 Hz, (obviously adjustable on the crossover to get the proper points) and then bumped the crossover up for SPL testing, will it actually work? since the driver is made to run IB, and below the tuning of the box, it'd pretty much be running IB anyways... can I do it? or should I not even try.
Pinky! Are you pondering what I'm pondering?
Yes brain, but how are we going to get the Edmonton Eskimos to wear lederhosen, AND tutus?
Since I am planning ot use my IDmax as an IB subwoofer, and since Iasca has an SPL portion to it's scoring, I got to thinking about box design.
so here's my theory, I want to know if it'll hold water, or leak like a sieve.
If I built a box, tuned to say 70 Hz, give or take, but a purpose built SPL box, and then ran my sub for SQ, lowpassed @ 60 Hz or so, with the midbass highpassed at 75 Hz, (obviously adjustable on the crossover to get the proper points) and then bumped the crossover up for SPL testing, will it actually work? since the driver is made to run IB, and below the tuning of the box, it'd pretty much be running IB anyways... can I do it? or should I not even try.
Pinky! Are you pondering what I'm pondering?
Yes brain, but how are we going to get the Edmonton Eskimos to wear lederhosen, AND tutus?
09-06-2004, 03:46 PM
#2
Yankee
Join Date: Aug 2004
Posts: 219
I am not sure about the rules. but why could you not just build a box with a removable port. have it to where you can jam it for sq tuned at like 30 hz and then pull the port out and it would be tuned at around 60. I have done it and it workes like a charm. Its not very difficult. You just have to find the right port size for the 60 hz port, and then be able to slide the 30 hz port in and fasten it with some 2" screws.
09-06-2004, 06:24 PM
#3
1000 Watt CAFz'r
Join Date: Oct 2003
Posts: 1,783
You need to get your hands on the Loudspeaker Design Cook book available here: www.solen.ca
In it, it explains how below your tuning frequency, the box loses control of the driver. Your idea has merit as an idea, but if you want to use your sub below the tuning frequency, expect a steep rolloff in response.
Adam
In it, it explains how below your tuning frequency, the box loses control of the driver. Your idea has merit as an idea, but if you want to use your sub below the tuning frequency, expect a steep rolloff in response.
Adam
09-06-2004, 07:41 PM
#5
50 Watt CAFz'r
Join Date: May 2004
Posts: 189
There are a couple things you could do
1. Have 2 ports of different length as previously stated and swap them
2. Have 2 ports and with both open is a certain freq and another freq with 1 plugged/capped (not my favorite idea)
But for IASCA you are only looking at 135db on a mic and you should be able to do that. IB gives you other benifits like a nice transfer function as well as room in the trunk for other equipment or just space.
But take Adams advice and take a look at the cookbook.
[ September 06, 2004, 08:42 PM: Message edited by: MDXMan ]
1. Have 2 ports of different length as previously stated and swap them
2. Have 2 ports and with both open is a certain freq and another freq with 1 plugged/capped (not my favorite idea)
But for IASCA you are only looking at 135db on a mic and you should be able to do that. IB gives you other benifits like a nice transfer function as well as room in the trunk for other equipment or just space.
But take Adams advice and take a look at the cookbook.
[ September 06, 2004, 08:42 PM: Message edited by: MDXMan ]
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