Coral 10L-17 Woofers

I picked up this set of Coral 10L-17 woofers today in mint condition. These 10 inch units will be used in a future open baffle project. Older Alnico woofers tend to be really efficient and have really nice bass tone.

I have discovered that Coral's, Foster and Fostex drivers are really efficient and work really well in open baffles.

Akai/Foster Open Baffles

Last week I picked up this pair of Akai SW-135 speakers that has Akai branded Foster driver in them.
In the original box these speakers are not much to listen to, in fact they are boxy and not to open on the sound stage.

I promptly removed the drivers and went down to Makers Lab to start my project.

This is the finished product and I think this forth rendition of my open baffle experiment turned out really well.

Once again with open baffles there is a really open sound stage, the three drivers are all designed to work together with minimal crossover which is a 16uf cap for the mid range and a 2.2uf cap for the tweeter.

Bass is exceptionally strong, tight and articulate in these speakers, mid range is nice and smooth and the highs are perfect for a cone tweeter, not as strong as in the horn tweeters.

Best suited with a single ended tube amp versus the push pull tube amp. I am going to keep an eye out for the vintage Akai speakers as they can be had for next to nothing and they have really good alnico drivers in them.

Next open baffle project Akai SW-135 Speakers

Just picked up this pair of Akai SW-135 speakers for the next open baffle project. These seem to have Foster or Coral Alnico drivers, perfect for open baffles.

The cabinets have been gutted and speakers are in perfect condition.

Foster Open Baffle Speakers

The latest open baffle speakers I have put together is a 3 way Foster driver speakers. The donor driver came from a pair of Noresco NEC-571  plus a horn tweeter that I picked up from a set of Zenith Allegro speakers.

This project turned out to be spectacular with the push/pull tube amp, almost in the league of openness and fullness as the Speakerlab Super 7's, almost. The Super 7's are really an amazing loudspeaker.

 The original Noresco speakers used a 10" Foster 25E33 alnico woofer with a massive magnet assembly crossed over to the Foster 8F3 three inch full range speaker. The original crossover was used as the crossover point between the woofer and the full range driver is around 650hz.

A foster horn tweeter was included to handle the high end as I found the 8F3 seemed to roll off in the highs.
A 2.2uf cap was used with a crossover point at 9000hz, it seems to have added the high end depth and sizzle that I like.

This combination came out way better than expected. Bass is full and clear, the mid range from the 8F3 is luscious and smooth, very deep and wide. the horn tweeter takes care of the highs in spectacular fashion.

Before I started this project I had an idea as to how this set up would sound, but it came out way better than I expected.

If this is what open baffles are supposed to sound like, then I am a believer now.

Aesthetics came out beautifully with the dark mahogany veneer.

12" Utah Pandore Open Baffles

Another project finished this week is the Open Baffled 12" Utah Pandore speakers.

More bass than the 8" Realistic Americana Open Baffle speakers that I did 2 weeks ago, there is also a compression horn driver for the highs.

these speakers sound very natural and I do not miss the boxed bass that are part of every other speaker.

The results of this project came out much better than my expectations. I am pleased as punch with theses speakers and will most likely keep with the 12" open baffle designs. Although I still have a few 8" coaxial driver that will be featured soon.

And of course these are being driven by a SET tube amp.

Very impressed....

Realistic Americana Open Baffle Speakers

Another idea planted in the depths of November is to start making open baffle speakers using vintage Utah, Realistic, Electro Voice, Knight and Lafayette full range, co axial and tri axial speakers.

The first one I  built was with a full range 8 inch Realistic Americana. I used a nice 3/4 inch plywood with a light mahogany veneer. These are drivers from the late 1960's into the early 70's. Made by Utah and re branded as Realistic. The frequency range is 45-18000hz with pretty high sensitivity.

The legs are from a pair of children chairs that I found at a thrift store.

I got a chance to sit back and listen last night and I liked what I heard. I had to bump the bass and treble for my taste. I found that they worked best around 2 feet from the back wall. I have read that it is best to do an open baffle with full range speakers, simplicity is the key with no crossover phase shift, or in other words coherent.

More to come later on my sound impressions, so far I prefer it to boxed speakers.

KLH Model 17 update

I managed to recap the Model 17 with some Solen metal polyester 5% caps which really help open up these speakers. I also have managed to get the majority of the cabinets back to their walnut veneer glory. Pictures of the cabinets when the job is done.

I really like these speakers and I can see the evolution from these speakers to the New Large Advents that were developed after Henry Kloss left KLH.

The bass is really full and melts into a very smooth mid range. Perfect with a single ended tube amp. I really like these speakers and can see why the Model 6 and the Model 17 have garnered internet attention.

Mid range is nice and forward which is what I like. Bass nice and solid and super tight being in a acoustic suspension box. Over time I tend to prefer acoustic suspension versus a bass reflex system. The bass may not be as low but it sure is tighter.

Update #2

The cabinets are done.

From this....

To this....