Intermediate step (Off Topic)

by GC, Saturday, July 16, 2005, 03:04 (4570 days ago)

Hi Bert and all,

A planning mistake, working/studying 56 hours a week is not a good combination with a DIY-hobby. The rare free hours I have left for speakerbuilding are late at night. My neighbours wouldn't appreciate it if I started routing out dozens of circles at those hours. I have had to put my Bold Step on hold (round 120 Hz tractrix horns).

Still, I keep having the itch and I get bored at night, so I dug up the old figure saw and made one 160 Hz horn. It's an odd combination of 4 mm MDF, straight square sections and pur-foam. :-D

It was finished today. I screwed in a Lowther PM6C driver and connected it to my amplifier. Quite horrible sound. Bright, loud and aggressive. I thought it was caused by reflections and resonances in the square horn. I left it playing for a while and it quickly solved itself. The amp was cold and the driver had been stored for over 6 months. It was breaking in! It got better, but of course there still wasn't any bass. Hornresp.exe suggested that with corner placement, there would be some bass, about 6-9 dB down. I pushed the horn into a corner and turned up the bass on my amp. Not quite an earthquake, but it you can follow the bassline well and the balance seems very natural. A rear chamber should help as well, but I couldn't be bothered anymore...

This is the largest horn I have built so far. Every time I build a bigger one, it sounds better. Clearer, cleaner, warmer, more open. The last one is strange, I expected longer and larger horns to be less open. Anyway, there is a very nice depth in the music now. I tried a few different recordings, ranging from computer-generated reggae to electric guitars and from acoustic pop to philharmonic classical. Most exciting was (for me) that this horn is really bad for French horns and really good for trombones. I play the trombone myself. ;-)

Building is fun. I should do more of it. I guess I can, now that I have rediscovered the very silent figure saw. :-) Let's see if I can build an even bigger horn, perhaps with bending ply this time.

Ivo

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Intermediate step

by GC, Saturday, July 16, 2005, 10:30 (4570 days ago) @ GC

Hi Ivo,

Thanks for sharing! You should buy a camera though, seeing things makes a lot clear... :-)

It was finished today. I screwed in a Lowther PM6C driver and connected it
to my amplifier. Quite horrible sound. Bright, loud and aggressive. I
thought it was caused by reflections and resonances in the square horn. I
left it playing for a while and it quickly solved itself. The amp was cold
and the driver had been stored for over 6 months. It was breaking in!

All Lowther drive units should break in that quick, even the new ones! :-D

Building is fun. I should do more of it. I guess I can, now that I have
rediscovered the very silent figure saw. :-) Let's see if I can build an
even bigger horn, perhaps with bending ply this time.

Please do, have fun and don't forget to share your experiments with us!

Ciao,

Bert

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Intermediate step

by GC, Tuesday, July 19, 2005, 03:11 (4567 days ago) @ GC

My next ambition:

A big frontloaded horn for my Lowthers, styled after the Voigt Corner Horn. It wil feature design elements from the original VOIGT Corner Horns, various vintage Lowther horns, most notably the Audiovector, because it has an interesting midrange horn arrangement.

We'll see if I can make such, with a handsaw and waste wood. Nothing ventured, nothing gained.

Greets,
Ivo

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Intermediate step

by GC, Tuesday, July 19, 2005, 09:33 (4567 days ago) @ GC

Hi Ivo,

We'll see if I can make such, with a handsaw and waste wood. Nothing
ventured, nothing gained.

Ambitious! Don't forget to listen to music in between work! :)

Ciao,

Bert

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For Bert -Voigt corner horn

by GC, Tuesday, July 19, 2005, 10:18 (4567 days ago) @ GC

Ever auditioned one of these Bert?
A friend has just bought one for his mono rig but hasn't set it up yet.

Brian.

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For Bert -Voigt corner horn

by GC, Tuesday, July 19, 2005, 10:24 (4567 days ago) @ GC

Ever auditioned one of these Bert?

Nope, is that the one with the "hide" driver at the bottom and the exit at the front-top?

A friend has just bought one for his mono rig but hasn't set it up yet.

Its time to come to the UK again...!

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For Bert -Voigt corner horn

by GC, Tuesday, July 19, 2005, 13:48 (4567 days ago) @ GC

Brian,

Are there/will there be pictures available online for this horn? I'd be very interested to see some. The drawings I have are very schematic and there is so much I don't know about this horn.

Just a simple pic of the reflector and inside the mouth would already help a lot.

Ivo

Ever auditioned one of these Bert?
A friend has just bought one for his mono rig but hasn't set it up yet.

Brian.

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For Bert -Voigt corner horn

by GC, Tuesday, July 26, 2005, 16:11 (4560 days ago) @ GC

My friend is hoping to pick it up along with a Lowther PM7A drive unit next weekend (was going to be last Sunday).
When he has got it installed I'll be over like a shot and snap some piccies.

Brian.

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For Bert -Voigt corner horn

by GC, Tuesday, July 26, 2005, 19:54 (4560 days ago) @ GC

Hi Brian,

When he has got it installed I'll be over like a shot and snap some
piccies.

Great, do make some detailed pictures to understand the whole construction if this is possible... :))

Ciao,

Bert

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Intermediate step

by GC, Tuesday, July 19, 2005, 14:10 (4567 days ago) @ GC

Hi Ivo,

Ambitious! Don't forget to listen to music in between work! :)

I am insane, but that's nothing new. :-P

I have one schematic drawing of the inside, which shows that the driver is placed "on the floor", firing into the back of the cabinet, followed by a 90 degree upwards bend into the horn. Then, the mouth is bent another 90 degrees, of course.

I don't think the 90 degree bend at the throat will work for my PM6Cs, a sure way to kill treble. It's also harder to build. My version will look something like this, only much deeper and with a reflector/extension above it:

[image]

I’m assuming that the reflector is part of the horn, BTW. It will be a half-size 80 Hz tractrix horn. I did some backwards engineering last night and I'm quite certain that's the horn Voigt put in his corner horn. Everybody says 70 Hz, but those numbers don't make sense at all. It all falls into place with 80 Hz.

It will take some drawings before I start, it's too complex to throw together on the spot. It's already getting out of hand... :-D

Back to my studies.
Ivo

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