Speaker Help Needed

[griff]

I have had these drivers sitting around my house for over 2 years after a failed attempt at making a DIY bookshelf system. The xo I had tried seemed to restrict the output of the driver so much that there was absolutely no midrange, so I essentially gave up on them.

Now, I need a new system and have searched every square inch of the net to find a DIY system that uses one or both of these components in a bookshelf design, but have come up with nothing!

If you know of a DIY speaker that uses either the SEAS CC17 RCY (H624) or the 27TFF (H831) please let me know, it would be greatly appreciated before I pull my hair out.

[gtforme00]

A challenge... hmm. I'll check one of my old David Weems books as he favored Seas drivers. In the mean time till I find that book:

I would like to help you, but am going to need as much info as you can give me about the design you tried. For example:
[list=1][*]Are the drivers in an enclousure?[*]Do you have frequency response curves for the drivers in the enclosure?[*]If not, do you have the measurement equipment necessary to get them?[*]Can you provide a schematic or description of the crossover you tried?[/list=1]

If you don't have the response curves, the worst case scenario is to use the manufacturers curves, but it's better than nothing. Just provide us what you can, and I'm sure that there will be helpful people to come along and assist with a successful design.

Best Regards,
David

[Inductor]

SEAS:
http://www.seas.no/seas_line/woofers/H624.PDF
http://www.seas.no/Prestige%20Diskan...FF_831ny06.pdf

Check for a 2. order xover at 2K5. Invert tweeter connections 180º as in the picture below.

[griff]

gtforme00 - I dont have the specs from the drivers, just the online specs as stated in Inductors post. I don't have the equipment needed to measure them unfortunately.

The enclosure I made was a 15 litre sealed box, 1inch MDF for a virtual size of 17 litres.

I have attached the XO i used in the project, and looking back over all my notes, there may be some pretty serious flaws. Its been a LONG time since ive been into DIY so I am hideously rusty, be gentle :P

[gtforme00]

I'll run the drivers through some modeling tomorrow to see what I can come up with. It's night here so you'll probably have an update waiting when you check tomorrow morning.

Regards,
David

[Inductor]

First of all, check for the polarity of the speakers (woofer and tweeter), they must have a red tag (or plus sign) on positive. Just checking... you must reverse polarity for one of them, for phase correction.

[gtforme00]

Agree with above, check driver polarity first. Then, check the wiring on your crossover. I would be embarrassed to admit the number of times I have wired up a crossover incorrectly.

I modeled your crossover in Speaker Workshop using the manufacturer's data for the frequency response and it looks like you did a pretty good job with the network design!



The one with the dip has both drivers with the same polarity. The flatter one is with the tweeter polarity inverted. Don't put much trust in any information below 500Hz.

If inverting one driver doesn't fix the midrange problem, then it's going to be difficult to have a much better design than you did without actual measurements.

Best Regards,
David