Hello Dave, thanks for your help with this.
Some pics below. First two are how it is now
And this is what I proposed earlier. Block up the existing driver cut outs, mount the 6.5" up firing and put a pipe from top panel which terminates at a distance which is the same as the middle of the driver when it was front mounted. Would that preserve the distance of the driver from the end of the line (Zd) ?
OK Dave many thanks for giving it your consideration. I couldn't work out if it had the desired effect, I hoped it would but without test gear I can't prove it one way or another.
So back to the original front firing plan it is.
I have been thinking of other FR drivers that might do what I require with a smaller volume than the 5.3. I have been looking at the SB Acoustics SB65WBAC25-4 which is a well regarded 2.5" which will fit in the old tweeter cut out exactly (will just need a chamfer to improve air flow) and the pipe from front to back panel will give enough volume.
The normal target for a sealed enclosure for the A5.2/3 would be 1.7 litres unstuffed for a Q of 0.707, Butterworth, max flat response. Adding damping (required) will make the box act larger.
Beyond that you are looking to remove as much of the back wave of the driver as much as possible so that it does not come back thru the cone and cause a time-smear.
Making the sub enclosure larger, gives more room for damping, or a midTL which makes for a low pressure enclosure with maximum damping effect,=.
Try the sealed pipe, then if you decide to it can be made leasky by drilling holes into the pipe from the back.
By making the box larger it will roll off sooner & slower. Given the high XO, that is not an issue.
dave
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Thanks Dave, you are very generous with your advice
Pipes are in but not ordered any drivers yet or chamfered the back of the cut outs. I am sure I will be back for advice on the stuffing in the near future.
I am very excited about this little project. I bought these speakers new in 1997 and they were my main speakers for 20 years. I loved the bass from these and the imaging was really good.
Then I started to really get my modified cdp and diy amps to a stage where they started to show up the P4's. The 3.5Khz low pass with single series inductor was I suspect letting some cone break up through. The ferro fluid in the tweeters dried up and I thought why not try something a little different.
It will be good to use them again even if they are in my second system.