Swan IV Treble Couple Crossover Help

[jbanneck]

Hi folks,

I need some help. I found a old project that I would like to finish, the Swan IV speaker system. I have an old photo copy of the article from SB from 1988 but can't read the value for C1. If have the article and can let me know that would be very helpful. Thank you, Jim

[leadfinger]

Hello Jim,

The Swan IV Treble Coupler c1 cap is 4.7mfd.

However.... in the year following article publication (1988) the original Treble Coupler was determined to be unsatisfactory and it was recommended that builders switch to a standard 12db L-R 200hz crossover with the bass boost added to the woofer section.

This is a 25 year old design so I hope you have all the drivers on hand and in good condition. The mids and tweets have not been available fo 15-20 years. The foam surrounds went bad on my 305 woofers after 10 years or so. I believe my mids and tweets are still ok, they have been in storage for a couple years....Dave

[jbanneck]

Hi leadfinger,

Thank you for the reply. I do have the drivers but they are in storage. I will have to open them up to see what condition they are in.

If you could forward me the article regarding replacing the Treble Coupler that would be great. You mentioned switching to a standard 200Hz LR crossover. However, I understand the mids and tweeters are crossed over at 2000Hz. DO you mean 2000Hz? Can you clarify?

Thank you,
Jim

[leadfinger]

Hello Jim,

Here is a brief summary of the Swan IV Speaker Builder article just to make sure we are talking the same project.

The Swan IV was designed by Joe D'Appolito and published in Speaker Builder 4/88, 5/88 issues. It is a 4 box system consisting of two 100 Liter woofer boxes each containing dual 12 in woofers and two mtm satellites each containing dual 5.25 dvc mids and a tweeter. The system is bi-amped at 200 hz between woofers and satellites. The satellites have a passive 2000 hz crossover between the dvc mids and tweeters. The article recommends 4 amplifer channels of 200 watts each.

The Pedal Coupler is the 200 hz bi-amp crossover with bass boost. There were no further articles on the project, just some discussion in reply letters and responces published is subsequent issues the following year.

Its my understanding the Pedal Coupler as published will work ok but a more conventional L/R crossover was preferred by most builders. If you want to research sutable crossovers I recommend reviewing the threads for; mox active crossover, and active filter board gb. I have spare empty boards from both threads that I can send you if you wish to complete this project.

I tried attaching a picture of mine which I plan to get out of storage and refurb when I have time, I hope it comes through.....Dave

[jbanneck]

Hi leadfinger,

Yes we are talking about the same project. I actually have the Pedal Coupler already built. At the time it was available and I bought it. It is still in the box, never opened.....

Anyway, my questions are currently regarding the passive Treble Coupler crossover in the satellites. The photocopy of the article is not so good anymore. The only thing I can't read was the C1 value. You said it was 4.7uF but looking at the single dot int he photocopy it looks like a single value. Anyway if 4.7 works that's great.

I have all the other issue of SB except 4/88 and 5/88 (no wonder). I will check out the following editions.

BTW, wow, what a beautiful job you did on the Swans you built.

Again thank you very much!
Jim

[Speedskater]

The pieces and parts for my "Treble Coupler" are too in storage. My boxes never looked as good as leadfinger's though. The "Pedal Coupler" parts were re-purposed and have since disappeared.
I wonder if Madisound still has any reprints of the entire article?
Now with cal mics and programs and DSP active cross-overs it might be interesting to re-visit the project.

[leadfinger]

Hi Jim,

Sorry, but I misread your first post. You said Treble Coupler, my brain saw Pedal Coupler. For the Treble Coupler passive crossover C1 is 8.0 mfd.
I built my pair probably in the late 90's. The mids and tweets were either off the market or superceded by newer models. The tweeter I used was a Morel clone of the D28 and the mids were a slightly newer version of the 5n412db. The tweets should last almost forever, the mids should last almost as long if you treat the rubber surrounds with silicone grease every few years. The Swan 305 woofers were discontinued by Madisound a few years ago but I am sure there are many sutable replacements if your foam is bad (it fails at the edges of the round area) or you could have new surrounds installed if needed. I picked up some surplus dvc woofers from Parts Express a year or so ago as replacements. Poly cone, rubber surrounds, similar t/s paramaters, they should work fine. My woofer cabinets are the larger 140 liter boxes, not the 100 liter boxes the article settled on, the larger boxes require less bass boost and amp power. If I can be of any more help just let me know.... Dave

[jbanneck]

Thanks Dave and Kevin,

I appreciate your help and insight. Now I just need to dig out those old drivers, make the passive crossovers, and finish the cabinets. I'll let you know how it goes.

Take care,
Jim

[rjv305]

I have both issues of sb mag,that deal with swan iv. I built the system,still using it,still sounds fantastic.If I knew how to upload the article to a fellow builder I would.