The Frugel-Horn Project

[LilMik]

Originally posted by chrisb
He was characteristically very enthusiastic when he first "discovered" the 126, and with good reason - in his speaker it certainly has been overwhelmingly accepted by all who've tried it. Indeed, he singlehandedly precipitated a temporary shortage in supply last year when Madisound's estimated inventory turns were overtaken by demand.

that's cool :-D

Originally posted by chrisb
In case this hasn't been discussed yet, what amp(s) are you using?

i tried my zen-amp, my aleph3, my gc's, my fathers einstein amp and avm amp and my crown pa-amp with 2*300 watt or so. always the same 'weightless' sound.

Originally posted by johninCR
Mike,

What kind of baffle are you running on your FH's? I went directly to an appropriately sized supra-baffle and I have a nice balanced response with surprizing bass response in my room with good corners. I did a quick test with some side additions on my Metronomes, and I can easily see how the FH supra-baffle must significantly change overall response.

i tried diffrent shapes and sizes; no problem, it's a test box, look does not matter. i circular 33cm baffle is the best.

i already tried to lift the response belwo 600hz or so with my EQ, but it did not help at all. i think the frequency response is pretty flat with a supra baffle. the 'weigthless' sound has nothing to do with baffle step loss imho.

regards
mike

[Dennis Hui]

Originally posted by planet10


The corner with the window won't be quite as effective as a solid wall but it is better then not having it. How close to the floor does the window get?

dave

PS: flat-paks are coming. They are now in their 3rd revision, and time to do them is opening up as we are close to finishing all the customer builds that landed on us in Sep/Oct.

dave

Hi Dave,

The floor is about 10 inches from the window. At one corner
there is actually a small section of back wall (about a 18 wide).
The rest of that side is a window.

Thank you for the information about the flat-paks.
I will email you about them.

Cheers,
Dennis

[johninCR]

Mike,

Now you've got me stumped. I have multiple pairs of 108EZ's. All were well used before I got them, although I do have one brand new pair that I haven't tried yet. I saw a measurement somewhere that showed a large dip in response around 1khz, but all of mine exhibit only a narrow dip of 2db or so. Maybe that's a break-in difference. I know I wouldn't like the broad dip.

Changes inside the compression chamber give you a very effective way to taylor the sound to your own taste. Not only does the net volume make a difference, but the material you use for fill and how it is arranged inside the chamber has a significant influence on tone.

Although I don't understand, I've read discussions about needing a proper coupling of horns to a room, and the volume of a room determines how large a horn it can support.

On the otherhand, I do find that small drivers sound different than large ones. I've posed that question a few times, but no answer. I think it is more than just polar response, and I'm pretty sure it's not just psycho-acoustic.

[Quinn]

My father is nearing in on the completion of a set wedgie horns. Now for my question:

Before he glues the side on the speaker, what kind of stuffing should be added inside the horn that are going to be inaccessable once the glue cures?

Thanks
Quinn

[Scottmoose]

Personally, I'd say none. All the damping you should need can be sorted via the chamber or around the mouth. Builders might have other ideas / suggestions though.

[chrisb]

Originally posted by Scottmoose
Personally, I'd say none. All the damping you should need can be sorted via the chamber or around the mouth. Builders might have other ideas / suggestions though.

I second that emotion. Start with light layer of 1/2" cotton felt or corrugated open cell foam on rear bulkhead of chamber, and perhaps side walls.

[doorman]

After a bit of experimentation with mine, I ended up pretty much as Chris has suggested. There's a tendency to overdo it!
Don

[johninCR]

My favorite so far with my FH 108EZ is using cans of vegetables to get the volume down to about 1850 cc's, with just enough open cell foam to keep them from rattling. I tried filling with plywood and mdf triangles resulting in a shape behind the driver like an anechoic chamber, but the sound is muffled. Maybe some varnish on the triangles to make their surface more reflective would be better, but I've pretty much decided to use concrete and imbed some of the triangles to break up reflections within the CC.

[LilMik]

Chrisb:

Originally posted by johninCR
Now you've got me stumped. I have multiple pairs of 108EZ's. All were well used before I got them, although I do have one brand new pair that I haven't tried yet. I saw a measurement somewhere that showed a large dip in response around 1khz, but all of mine exhibit only a narrow dip of 2db or so. Maybe that's a break-in difference. I know I wouldn't like the broad dip.

talking about the dip, i think it is there. i did not measure my 108es, don’t have a mic, but i can hear it. the dip does not sound as bad as it looks like on paper, but i can hear it. vintage saba fullrangerdrivers have a 10db dip in this range too, and many people say that sabas sound very good. i can confirm this.

interesting that your drivers don't have a dip. i do not think that 2db is something to worry about. i only saw two measurements that did not show a suckout. one is from a dealer and the other measurement is from fostex. maybe things change after a few thousand hours “burn-in-time”. if so, that good :-).

do you still have your own measurement? could you post them?

looking carefully at fostex measurement in the "recommended enclosure" pdf, you can see a broad dip as well from 600Hz to 1200Hz, exactly where the measurement from the german magazin Hobby Hifi shows a dip. if you consider that: a) fostex is using heavy smoothing and b) the backhorn does have significant output up to 1000Hz, i think fostex own measurement indicates that the dip, if you measure the fostex in an infinity baffle without support from the backhorn, is deeper than the 5db you can see in the “recommended enclosure” pdf. just a guess.

for everyone how wants to read more about “the dip”, here is a link for you: Is the FE 108EZ a bad Driver?

especially look at post 58: http://www.diyaudio.com/forums/showt...70#post1064170

in germany, a few guys use a fronthorn that, if the dimensions are correctly, manages to fill up the gap. they are using a circular 45cm expo-fronthorn that is 6cm to 10cm deep. look at the picture. never tried it. actually, if I use my EQ to fill up the gap, the sound is not as good as before. stange. but it’s a cheap EQ, so…

Originally posted by johninCR
Changes inside the compression chamber give you a very effective way to taylor the sound to your own taste. Not only does the net volume make a difference, but the material you use for fill and how it is arranged inside the chamber has a significant influence on tone.

thx. i already played with stuffing. i can hear a difference, but whatever i did, the sound was always kind of ‘thin’.

quinn:

Originally posted by Quinn
Before he glues the side on the speaker, what kind of stuffing should be added inside the horn that are going to be inaccessable once the glue cures?

initially, i had a kind of a “hollow sound” or a “hollow midrange coloration” with my frugels i could hear with some male voices. not much, but it was there. especially with my zen-amp. after lining the last 50% or so of the horn path with thin cork, it was gone. it has no influence on the bass. the hint with the cork comes from audio-resolution. look here http://www.audio-resolution.com/zhorn/herukamain.html

so far i am the only one who did this with his frugels.

imho it is very impotant to play a bit with the frugels until you get what you want. same is true with ron's austins.

Regards
Mike

[johninCR]

Mike,

I've been in a construction frenzy for a few months, but will start a measurement phase quite soon and I'll measure everything I can think of.

My Frugels haven't shown any hint of hollow sound, but I used 15mm for the horn panels and a center spine/brace through the first few segments. I also filled in the square corners at the bends and used a combination of laminated MDF and plywood. Before putting the sides on I applied 1 coat of natural varnish to the interior of the horn. I took these extra steps to improve the width/height ratio of the horn segments and reduce losses within the horn, since I planned to use 108's. I have no damping at all in the horn, so maybe my construction variations make mine a little more lively and less colored. To me they sound worlds better than my Fostex horns, which are very forward and shouty in the upper mids (I attribute to the flat CC rear wall so close behind the driver), boomy in the bass, and don't image as well (I believe due to the front mouth).

Thanks for that cork tip, because my own rework of the FH horn into a different layout (see the Tombstone thread) has some kind of resonance in the 200hz range that I need to cure. I'm not sure if it's caused by my undamped V-shape CC or the one long 70cm+ conical segment. The closer to square mouth did pay dividends with more bass even without stuffing them in a corner or using a deflector. We'll see how they measure in comparison. They were easier to build (no angles except to create the final segments) and don't need a supra-baffle. Although they look interesting, they aren't nearly as elegant as my FH's.