conical horn damping material...

[pauldune]

first post on this forum, crossover from tubeamps

I'm building a conical horn, like this:Conical Horn with Markaudio Alpair10 FR

Only i'm building it with a Tangband W5-1611sa.

The wood around the speaker in the box should be lined with 8mm felt, and some BAF at certain places.

Can I use 15mm Pritex ("tooth foam"?) instead of the felt?

I have quite a stash of it out of packing material from Hewlett Packard servers.

And would it be good to line the entire horn with it? Or should the horn be as smooth and hard as possible?

The idea was to cancel reflections in the horn, but maybe the sound wave cant "travel" easely to the horn opening on the backside anymore...

Gr. Paul

[Scottmoose]

Suck it an see really, Without seeing the details of your design, it's hard to predict in advance, and frankly, it may not make much difference anyway as only you know what sounds good to you. So long as it's open-cell foam, then it should do a decent job of damping things; start with little & add if you need more to suit your personal requirements.

[pauldune]

Originally Posted by Scottmoose

Suck it an see really, Without seeing the details of your design, it's hard to predict in advance, and frankly, it may not make much difference anyway as only you know what sounds good to you. So long as it's open-cell foam, then it should do a decent job of damping things; start with little & add if you need more to suit your personal requirements.

The link provided is EXACTLY like mine; only with a different speaker. The enclosure Henkjan uses was designed for the tangband w5-1611sa, he adapted it for the alpair.

The foam I have is airtight. There were also open foam parts, but i threw them away, because they didnt damp at all; you could put them in front of your mouth and speak through them and the sound didnt change at all. The One I have now, considerally damps sound...

But I asked it because I read about some designers who state that their horns sounded better when they painted it with high gloss paint.
And there IS a lot of difference between vanilla MDF, high gloss painted MDF, and MDF with pritex glued on it

gr. Paul

[Scottmoose]

You've lost me in the ramble I fear. Open cell foam is somewhat more diffuse than close cell (which does not mean it's gossomar-light); the latter merely tends to take up volume & is relatively ineffective at damping.

Re MDF, it's a pretty poor choice of material for any LF cabinet (horn or otherwise), but it varies like any other sheet material, so naturally such things can make a difference in some cases.

[pauldune]

Originally Posted by Scottmoose

You've lost me in the ramble I fear. Open cell foam is somewhat more diffuse than close cell (which does not mean it's gossomar-light); the latter merely tends to take up volume & is relatively ineffective at damping.

Re MDF, it's a pretty poor choice of material for any LF cabinet (horn or otherwise), but it varies like any other sheet material, so naturally such things can make a difference in some cases.

I'm sorry, didn't know that of the foam. I googled around a bit and I think I have open cell foam. I was mislead because of the two different types I had in the boxes. They looked the same, but one type was completely transparant to sound, and it seemed to me that it couldn't be used for damping. The other one, on the other hand, damped sound pretty good.
If you put it to your mouth, and try to blow through it, with the first type there is no resistance at all, and with the second you will have to blow a bit harder to get air through it.

I knew that MDF isnt the best material, but it will have to do. Multiplex is much to expensive (for me) to build a prototype with. And i'm counting a bit on the "partition walls" (dont know if I use the correct english words) to keep it stiff. It was also one of the reasons i wanted to furnish the complete inside of the box with the foam. Still dont know if its good or bad. Sound should be as neutral as possible...

greetings, Paul

[Henkjan]

Hi Paul. Roland (who designed the horn) might be able to better answer the question on the felt vs foam, but my gut feeling is that they will be different in lower midrange. the quick way is to test it, should be easy because it is accessable through the driver hole.

btw: dou you have the original lay-out for the W5-1611 horn? the difference is in the BAF in the horn mouth, the W5 does not need it.

[pauldune]

Originally Posted by Henkjan

Hi Paul. Roland (who designed the horn) might be able to better answer the question on the felt vs foam, but my gut feeling is that they will be different in lower midrange. the quick way is to test it, should be easy because it is accessable through the driver hole.

btw: dou you have the original lay-out for the W5-1611 horn? the difference is in the BAF in the horn mouth, the W5 does not need it.

Hey Henkjan,

Yes I have the original layout; I completed them a few hours ago.
They sound ...not very good...
I tried to put more damping material in them, (more BAF around the speaker)
and put some damping material in the horn mouth. now the nosy sound is better, but still not as it should be. They lack brilliance; I miss details in high frequencies. For example acoustical guitars with steel strings sound a bit as if they have nylon strings... I own both type of guitars so I am well aware how they should sound. Its not as dramatic as I state here, but it seems to lack a "sparkle".

The things I thought a fullranger would excel in, like pin point stereo imaging and depth in sound stage, were'nt much better than my previous speakers. (mordaunt short ms908i)

Could this all be on account of the damping material?

I didnt use any form of filter, and of course they need some burn in time...

I include some photos as how I build them...


If someone has any advise on how to improve them, please...

Otherwise i'm gonna keep using my old speakers.

Gr. Paul

ps Henkjan, I think I bought the speakers at your company. (Juoigâ)
Do they sound a lot better with the alpairs?

[Henkjan]

1st comment: allow them to run in properly, put a CD on repeat over the weekend or so. if that's done, play a bit with the speaker placement. They should give you great imaging and depth, I found them way better than e.g. a Needle in this point.

The lack of brilliance may be (partly) caused by the listening room, I had a rather disappointing experience with the A10 version of this horn when I took them to a DIY event and they sounded like someone closed the curtains in front of them. back at home they were as good as before. But also, this is not the highlight of the W5-1611, they have a more 'friendly' high. and as I described, if without correction, there is a slight midrange plus, that may be described as nosy by some. Putting damping in the horn's mouth will mainly reduce low output. if you want a more neutral sound, you'll need a correction filter of some sort.

if after running them in (and allowing your ears/brain to get used to their sound) you still find the high disappointing, try them in another room first. if this does not work, try an "ambient tweeter": a up or rear firing tweeter with a very small cap in series so it will only add the top octave 'to the room'.

and on the question A10 vs W5: yes, imho the Alpair is a lot better (which is good, given their price compared to the W5's price... no free lunch again).

[pauldune]

Originally Posted by Henkjan

1st comment: allow them to run in properly, put a CD on repeat over the weekend or so. if that's done, play a bit with the speaker placement. They should give you great imaging and depth, I found them way better than e.g. a Needle in this point.

The lack of brilliance may be (partly) caused by the listening room, I had a rather disappointing experience with the A10 version of this horn when I took them to a DIY event and they sounded like someone closed the curtains in front of them. back at home they were as good as before. But also, this is not the highlight of the W5-1611, they have a more 'friendly' high. and as I described, if without correction, there is a slight midrange plus, that may be described as nosy by some. Putting damping in the horn's mouth will mainly reduce low output. if you want a more neutral sound, you'll need a correction filter of some sort.

if after running them in (and allowing your ears/brain to get used to their sound) you still find the high disappointing, try them in another room first. if this does not work, try an "ambient tweeter": a up or rear firing tweeter with a very small cap in series so it will only add the top octave 'to the room'.

and on the question A10 vs W5: yes, imho the Alpair is a lot better (which is good, given their price compared to the W5's price... no free lunch again).

Thank You, Henkjan.

Another room isnt an option for me, because they will have to perform in the room they are standing in right now. I'll consider using a filter. Any recommendations? notch/ bafflestep? I have some tweeters lying around, I will try that too. Ill take out the damping of the hornmouth as well.

I wish I could hear the alpair 10, if its really good, I probably would buy it.
But I dont want to spend 300 euro's and be disappointed again.

The break-in of the speakers, could it be done with a say 20 Hz tone? I dont want to have to put constant music on them, most of the time there is someone at home, and they wouldn be happy with loud music al the time. but at 20 hz the sonic output of the speaker would be minimal, but it would move none the less.

gr. Paul

[Henkjan]

about running in: what I do is to wire 1 of the speakers out-of-phase, and then put them with the drivers facing each other realy close together. (and with these speakers also stuff the horn mouth then). I would use normal music, since you'll not only want the surround to run in, but the entire driver.

I'll dig in my mail-archive on the tweeter, I had a mail once of someone with a similar experience, he added an ambient tweeter and was more than happy. you could use his setup as starting point

where in our small country do you live?