DIY amps and speakers

Lensman · « **on:** 13 Apr 2005, 02:55 am »

I am building a pair of full-range driver transmission line speakers built around the Fostex FE167E driver. While waiting for the cabinet maker to finish the enclosures, I've been upgrading my amp with some circuit changes and new components. At the same time I've been designing and tweaking the equalization network for the speaker drivers. Anybody else in the NC Circle doing DIY projects?

I visited foam boy (BrunoB) this past Saturday. Under flashlight escort I crouched and entered the foam igloo (cocoon). Listening in an environment totally devoid of reflections certainly enhances the imaging on a stereo soundtrack. HF were very subdued, but the information was there. Sibilants vanished. The LF were less articulate, probably because of some questionable port tube modifications (i.e. the cardboard toilet paper tube!) and partially opened rear wall of the speaker enclosures. After becoming acclimated to Bruno's foam igloo, I noticed that even pouring milk into a glass sounds a bit shouty.

Lensman

BrunoB · « **Reply #1 on:** 15 Apr 2005, 06:37 pm »

Quote from: Lensman

... HF were very subdued, but the information was there. Sibilants vanished...

Hi Rob,

subdued (lacking in vitality, intensity, or strength according to the Webster online dict) is an interesting comment. I believe I have a very detailed and sweet treble but still a bit hot above 5-6K. Sibilants are still there but they don't hurt except with some overly bright recordings such as Sting's Sacred Love.

About LF, my experience is that changing the speaker position has much more influence on the bass than the loading of speaker. The bass was not as good as it was a year and half ago (when Carl came for listening). But, recently, I moved the speakers forward and change the position of the sofa and there was a substantial increase in bass without adding boominess (big change with the CD Peter Gabriel "UP"). I know that there is an optimal set of positions in the sound cocoon and the measurement equipement that I bought will help me to find it.

Good luck with your DIY transmission line and hopefully I would still have the opportunity to listen to them before I leave.

Bruno

Lensman · « **Reply #2 on:** 16 Apr 2005, 03:26 pm »

hey Bruno,

I didn't think the treble was too hot above 5-6k. My impression was that it was pretty well controlled. That's what I meant by subdued. Your system is very detailed and was a real pleasure to listen to. Zero fatigue and no headache after listening in the cocoon!
I want you to come over and listen to my system if the cabinet maker ever finishes my enclosures. I want your advice on treating the room.

mensch, du kannst gut Deutsch! Ich bin echt beeindruckt.
Rob

Carlman · « **Reply #3 on:** 16 Apr 2005, 03:44 pm »

I had an unplanned cocoon demonstration yesterday when I stopped by Bruno's with my wife.

I think Bruno's system is the best I have heard it at the moment. He's got the 'total-music-immersion' factor done... and the imaging was amazing. He played 'Up' by Peter Gabriel and I was stunned at the imaging quality. He played "Photograph" by Deborah Swank and it was a very 'intimate' sound. I had to borrow the cd I liked it so much.

It was definitely better at Bruno's place, though..

The bass is perfect now... it's deep and clean... no boominess or added 'warmth'. The midrange and highs were very accurate to real life. I wouldn't use the adjective 'sweet' because to me 'sweet' means colored, rolled-off, or something else... instead I'd call it 'true to life'. It was among the truest I've heard.

If there was a weakness, I'd say it was in the amplification. I'm not nuts about the way digital amps do things... it's like it gets really close to realistic and stops. (hard to describe) I'd like to hear Bruno's system with one of my integrateds... maybe we'll get that chance?

However, part of what's happening in Bruno's system is synergy. So, I may be wrong... and his sound cannot be improved that last 1% with different amplification.

My wife did not approve of the aesthetics of the cocoon, but she readily appreciated its effects. She had nothing but positive comments to say about it.... and she understood just a little more of the mind of an audiophile..

Thanks for your hospitality, Bruno!!! and for the chocolate!

Take care,
Carl

Lensman · « **Reply #4 on:** 16 Apr 2005, 03:57 pm »

"My wife did not approve of the aesthetics of the cocoon"

Carl, admit it. She was horrified!!

Only a batchelor would have a cocoon.

Lensman

Carlman · « **Reply #5 on:** 16 Apr 2005, 04:00 pm »

Believe it or not, the pumpkin harvest print tablecloth (or 'bass enhancer) got the highest disapproval.

Lensman · « **Reply #6 on:** 16 Apr 2005, 04:04 pm »

"Believe it or not, the pumpkin harvest print tablecloth (or 'bass enhancer) got the highest disapproval"

hmm, I didn't realize it was a bass enhancer. I thought it was Bruno's idea of spiffy interior design

BrunoB · « **Reply #7 on:** 16 Apr 2005, 04:30 pm »

Quote from: Lensman

"Believe it or not, the pumpkin harvest print tablecloth (or 'bass enhancer) got the highest disapproval"

hmm, I didn't realize it was a bass enhancer. I thought it was Bruno's idea of spiffy interior design

Well, these were on sale at Wall Mart ... I had a lot of surface to cover.

BrunoB · « **Reply #8 on:** 21 Apr 2005, 03:12 am »

Quote from: Carlman

If there was a weakness, I'd say it was in the amplification. I'm not nuts about the way digital amps do things... it's like it gets really close to realistic and stops. (hard to describe) ...

Digital amps have faster transients (see comparison here) . I wonder if digital amps are more life like than other amps in this respect?

Bruno

Lensman · « **Reply #9 on:** 21 Apr 2005, 03:18 am »

hey all

I stopped by the cabinet maker today to check on my speaker enclosures.
They have been veneered but not sprayed. Bruno, I was hoping to have you over to hear them before you leave for Europe.

I'm tired of listening to drivers with no boxes

Lensman

Lensman · « **Reply #10 on:** 25 Apr 2005, 01:34 pm »

hi all,

After almost exactly 1 year my speakers are finally set up. I'm still voicing them with an impedance correction circuit, stuffing, port tube length, etc., but I think I'm pretty close to where I want to be.
Give me a call (o.k., a forum message) if you'd like to come over and see/hear them!

Lensman

BrunoB · « **Reply #11 on:** 28 Apr 2005, 12:20 am »

Quote from: Lensman

hi all,

After almost exactly 1 year my speakers are finally set up. I'm still voicing them with an impedance correction circuit, stuffing, port tube length, etc., but I think I'm pretty close to where I want to be.
Give me a call (o.k., a forum message) if you'd like to come over and see/hear them!

Lensman

I had the chance to listen to Rob's speakers. These are vey nice. I will provide more details later. We also tried to build a sound cocoon in the living room for testing purpose. I took some picts that I will provide also in another post.

Bruno

Lensman · « **Reply #12 on:** 28 Apr 2005, 03:38 pm »

hi All,

Bruno came by and made some good observations. He noticed a sidewall reflection (which has now been foamed). Also, he noticed some imaging issues. After he left I did some precise measurements and found that the speakers were not properly positioned equidistant from the listening position. I've repositioned them, and now the imaging is much better. The drivers are now more directly aimed at the listener. By using the center rear carpet spikes on the enclosures, I tilted them slightly forward to bring out more HF detail. These full-range drivers tend to beam HF...

We also experimented with a mini-cocoon (Bruno's suggestion).
Sounded better, but was an interior design nightmare!.

Lensman