Altec MLTL with Model 19 drivers

[automojo]

QuietKote from PE works well-used it on my old Klipsch KG's-before I got back (to my senses and) into the Heils again-works great and is black.
I'm not sure with those specific horns, but 2 or 3 coats cured the midrange ringing on the Klipsch Tractix horns.
Of course if you want to remove it later-this would be difficult.
I also used acoustic foam around my AMT's-to prevent the midrange frequencies from wrapping around the AMT housing and cancelling each other-really cleaned up the midbass response IMHO, and also improved the imaging-but of course leave the back open. This may in fact slightly reduce the efficiency/sensitivety of the Heil realitive to the other drivers-which may be helpful. If it does-it's a small amount-but some ears are of course more sensitive.
You can also put foam pieces in the "V" voids on the top and bottom to prevent any possible wave defraction.
I'm not sure if this helps alot- but it makes sense!?:thmbsp:

 

[westend]

Before I cover the immaculate horns with a damping product, I'd like to know what others are hearing regarding "ringing". I'm just not hearing it.

Mojo, I did follow your other threads about the Heil and foam so I cut triangles and placed them on the bottom spaces of the Heil. Since I am using them as a super-tweeter, there is no midbass concern.

 

[kyle]

You should try something removable first before messing up your horns. If you press either Duct Seal (available at Home Depot) or plasticine into the outside depression of the bells you will likely find that they will be damped enough. I only use one bar of duct seal on one side and it's enough for either 811's or 511's to be non-ringing. If you don't notice a difference you can remove it easily. If you notice a big change add more or go for the full coating. Many people hear a major difference but many don't. I've never heard anything that I would attribute to horn ringing but I left the duct seal in anyway.
Kyle.

 

[Russellc]

Before I cover the immaculate horns with a damping product, I'd like to know what others are hearing regarding "ringing". I'm just not hearing it.

Mojo, I did follow your other threads about the Heil and foam so I cut triangles and placed them on the bottom spaces of the Heil. Since I am using them as a super-tweeter, there is no midbass concern.

I never found it to be that big of a deal either. Frankly, I'd rather tolerate a little "ringing" which I dont find that offensive, rather than slathering my horns with goop, which I do and must be a fantastic dust magnet!

That said, my horns are 511B, later ones where Altec removed the little center brace down in the throat, and cut a few weld points and filled them with a rubbery material, so may be a little less "ring prone" than other versions.

Russellc

 

[westend]

Can somebody please tell me what they are hearing when their Altec horn is "ringing"?

My thoughts are that since the horn is securely fastened (through bolted) into a frame, any "ringing" is damped. As I posted above, there is some resonance at very high volume but I believe this to not influence what I'm hearing.

Snap, I will experiment further with this by doing some mass damping to the horn and secure foam around the bell as AB has suggested. I'm trying to keep an open mind about the "ringing" but I'm biased that this may be fixing a problem that doesn't exist, in my case.

Please folks, tell me what you are hearing about "ringing". Maybe a before and after treatment anecdotal appraisal would do it.

 

[doucanoe]

Here's some anecdotal...

Numbdiver (Rick ) went to great lengths to reduce any perceived or unperceived "ringing" in his Altec horn 2-ways by the application of a adhesive backed sound damping material and brought them to my last get together. I don't recall the material he used exactly but by all accounts and after physically seeing the finished product, have no doubt that it would do the trick if any "ringing" was audible. He wanted me to listen to them and get my opinion on whether it was an improvement or not.

I have owned many Valencia's and other Altecs that used the 811/511 horn and after listening to his treated horns can honestly say that I noted no significant improvement in the horns tone or personality. Not having a untreated horn pair to listen to for comparison was the big flaw in the test but I believe I have heard enough of them to say that if anything, I thought it pulled a bit of the liveliness out of a horn/driver combination that I am pretty familiar with. To be fair though, that could have had much more to do with set-up, room, gear or a zillion other things including being more concerned about the get-together than seriously listening to (or listening long enough) speakers and evaluating what I was hearing.

You may want to drop him a line and ask what his conclusions eventually were.


I do know many that swear by the improved results of the process so I wouldn't say that it's not worth trying out. Particularly if you can apply something removable that will not damage.


RC

 

[djnagle]

Hey RC, I had the same experience until I had an untreated horn and a treated horn side by each. I use Dynamat from the car audio stores and that stuff rocks. It is made for dampening whole car side panels and is really effective no matter the size.

I friend of mine is a Ph.D. in NVH (noise, vibration, harshness) and teaches at Michigan Tech. I called him about Dynamat and he said that it is the better commercially available product on the market that will dampen the entire freq range.

 

[automojo]

I did the Quiet Kote more or less as a upgrade-I got the idea @ Econowave. I can't say I heard any difference-but with the KG's you never saw the horn anyway- and since I had it laying around-why not?
Those Altec horns look way more substantial then the thin KG horns-I think I would perhaps leave them as is-as they look nice. The biggest thing I would think. and biggest possible improvement in sound, would be to be to decouple it from the woofer box, and Heil.
The other train of thought is-if ringing was a huge problem- you would think some manufactors would treat their horns-or at least recommend it in ceratin applications etc.

 

[westend]

Here's some anecdotal...

Numbdiver (Rick ) went to great lengths to reduce any perceived or unperceived "ringing" in his Altec horn 2-ways by the application of a adhesive backed sound damping material and brought them to my last get together. I don't recall the material he used exactly but by all accounts and after physically seeing the finished product, have no doubt that it would do the trick if any "ringing" was audible. He wanted me to listen to them and get my opinion on whether it was an improvement or not.

I have owned many Valencia's and other Altecs that used the 811/511 horn and after listening to his treated horns can honestly say that I noted no significant improvement in the horns tone or personality. Not having a untreated horn pair to listen to for comparison was the big flaw in the test but I believe I have heard enough of them to say that if anything, I thought it pulled a bit of the liveliness out of a horn/driver combination that I am pretty familiar with. To be fair though, that could have had much more to do with set-up, room, gear or a zillion other things including being more concerned about the get-together than seriously listening to (or listening long enough) speakers and evaluating what I was hearing.

You may want to drop him a line and ask what his conclusions eventually were.


I do know many that swear by the improved results of the process so I wouldn't say that it's not worth trying out. Particularly if you can apply something removable that will not damage.


RC

Thanks, Ron. This is just the kind of appraisal I was looking for, thorough and honest. What's particularly interesting is the aspect of "liveliness", I am real sensitive to things like that. This part of the reason I'm reluctant to try any tough non-reversible damping modifications.

BTW, expect a call in a little bit.

Hey RC, I had the same experience until I had an untreated horn and a treated horn side by each. I use Dynamat from the car audio stores and that stuff rocks. It is made for dampening whole car side panels and is really effective no matter the size.

I friend of mine is a Ph.D. in NVH (noise, vibration, harshness) and teaches at Michigan Tech. I called him about Dynamat and he said that it is the better commercially available product on the market that will dampen the entire freq range.

I've used Dyanamat and similar for car audio installs. It is probably the best for damping. Ease of installation is also one of it's strong points.
Dennis, can you elaborate on the improvement you heard after applying the Dynamat?

I did the Quiet Kote more or less as a upgrade-I got the idea @ Econowave. I can't say I heard any difference-but with the KG's you never saw the horn anyway- and since I had it laying around-why not?
Those Altec horns look way more substantial then the thin KG horns-I think I would perhaps leave them as is-as they look nice. The biggest thing I would think. and biggest possible improvement is sound, would be to be to decouple it from the woofer box, and Heil.
The other train of thought is-if ringing was a huge problem- you would think some manufactors wouls treat their horns-or at least recommend it in ceratin applications etc.

Thanks, also what I'm trying to sort out, is there a substantial difference in damping the horn.

I, also, thought about the decoupling aspect. I did install felt on the bottom of the sleds and the Heil has a rubber cushion on the bottom. I will revisit that part of the build in the future, I would think that some of the modern acoustical foams or a thick piece of felt might help. What type of material or construction do you think would be best for this?

 

[westend]

Testing horns, foam on front and 10+ lbs. of Vigoro fertilizer on the back. If there aren't positive results, at least my plum trees are going to be growing

 

[AndyB]

IMHO, I think that Altec horns benefit from being decoupled from the bass bins. I think some of the lower hertz induce some haze and reverberation into the horns and color the higher hertz. It is kinda like the hum in your amp that "goes away" when the music plays. Altec did produce a number of cement and tar filled HF horns. Some rigid foam and several wire ties cinched up tight could prove the ringing theory quickly. Nice speakers Lance!

Thanks,
Andy

 

[Altec Best]

Can somebody please tell me what they are hearing when their Altec horn is "ringing"?

My thoughts are that since the horn is securely fastened (through bolted) into a frame, any "ringing" is damped. As I posted above, there is some resonance at very high volume but I believe this to not influence what I'm hearing.

Snap, I will experiment further with this by doing some mass damping to the horn and secure foam around the bell as AB has suggested. I'm trying to keep an open mind about the "ringing" but I'm biased that this may be fixing a problem that doesn't exist, in my case.

Please folks, tell me what you are hearing about "ringing". Maybe a before and after treatment anecdotal appraisal would do it.

Hey Lance FWIW GM always recommended to me WRT any 511 or 811 to just cover the outer edge first with pipe insulation that maybe good enough.If not you could always move on to other damping products.All metal horns resonate especially Aluminum.It's hard to explain how it sounds because it will sound different to everyone.I think Andy B explained what I hear.To me it sounds like colorized Ultra HF that lowers the clarity and it isn't crisp (HF)IMO.Let me try to explain a little,to me the music notes sound like they last too long instead of being crisp fast they are (resonating/ring) I hope this helps a bit.To you it may sound different dunno.Altec knew this, it is especially noticeable with their large format HF drivers.As to why they made Tar-Filled Multi's and Aquaplased Multi's & 511E's.

The insulation I'm talking about is the round 1/2" foam pipe insulation.You wrap the outside edge of the horn top & bottom all the way around back to the mounting flange.I have a picture somewhere of Steve Mac's Horns that he did.This was his first trial I think he replaced the foam with longer pieces after this pic was taken.Here is what GM recommends.And if you don't like it should take all of about 2 seconds to remove.

 

[djnagle]

The difference I heard was in the upper freqs. Like maybe 10khz and above. There was a ringing in that area that fatiqued me in minutes. Now that I write this, I remember you are using a tweet so it might not be an issue. I was using it two way.

 

[automojo]

As far as material goes- i know the rubber piece works well with the Heil I can't recall how the horn was attached, but even silicone, or rubber washers on any bolts should do the job.
I worded my last response wrong-I meant to say decoupling the drivers can make a big difference
Your woofer box is pretty stout and that should help alot.
Interesting take on the loss of horn livelyness with the damping-perhaps losing a bit of it's voicing as well. PWK used plywood as part of his voicing and little damping. Trying to damp the boxes of my KG's killed the sound-1 piece of foam to break up standing waves was all that was needed. My AMT3's need the cabinets full of damping material.
I know sometimes bracing a box-couples and moves the first panel vibrations to the next. Along with thick enough cabinet material the proper amount of dampening (stuffing) materal seems to be the best choice depending on your design goals. Sub boxes are another story.
I have to agree alot of newer speakers drivers are over damped to a point of strangeling the musicality right out of them.

 

[westend]

IMHO, I think that Altec horns benefit from being decoupled from the bass bins. I think some of the lower hertz induce some haze and reverberation into the horns and color the higher hertz. It is kinda like the hum in your amp that "goes away" when the music plays. Altec did produce a number of cement and tar filled HF horns. Some rigid foam and several wire ties cinched up tight could prove the ringing theory quickly. Nice speakers Lance!

Thanks,
Andy

Thanks, Andy. Yeah, decoupling the sled from the cabinet might be an improvement. I'll try it.

Hey Lance FWIW GM always recommended to me WRT any 511 or 811 to just cover the outer edge first with pipe insulation that maybe good enough.If not you could always move on to other damping products.All metal horns resonate especially Aluminum.It's hard to explain how it sounds because it will sound different to everyone.I think Andy B explained what I hear.To me it sounds like colorized Ultra HF that lowers the clarity and it isn't crisp (HF)IMO.Let me try to explain a little,to me the music notes sound like they last too long instead of being crisp fast they are (resonating/ring) I hope this helps a bit.To you it may sound different dunno.Altec knew this, it is especially noticeable with their large format HF drivers.As to why they made Tar-Filled Multi's and Aquaplased Multi's & 511E's.

The insulation I'm talking about is the round 1/2" foam pipe insulation.You wrap the outside edge of the horn top & bottom all the way around back to the mounting flange.I have a picture somewhere of Steve Mac's Horns that he did.This was his first trial I think he replaced the foam with longer pieces after this pic was taken.Here is what GM recommends.And if you don't like it should take all of about 2 seconds to remove.

Thanks, AB. I have some of that insulation, in stock. I'll be trying that out, too. Now that you mention GM, I seem to remember him suggesting a horn treatment.

The difference I heard was in the upper freqs. Like maybe 10khz and above. There was a ringing in that area that fatiqued me in minutes. Now that I write this, I remember you are using a tweet so it might not be an issue. I was using it two way.

That might be part of it, DJ, the crossover point. On this crossover, it's a 24db slope from the horn and to the Heil and the point is at 7000 hz. That might be out of the range of any "ringing". I'll set a higher point and see if the "ringing" emerges.

As far as material goes- i know the rubber piece works well with the Heil I can't recall how the horn was attached, but even silicone, or rubber washers on any bolts should do the job.
I worded my last response wrong-I meant to say decoupling the drivers can make a big difference
Your woofer box is pretty stout and that should help alot.
Interesting take on the loss of horn livelyness with the damping-perhaps losing a bit of it's voicing as well. PWK used plywood as part of his voicing and little damping. Trying to damp the boxes of my KG's killed the sound-1 piece of foam to break up standing waves was all that was needed. My AMT3's need the cabinets full of damping material.
I know sometimes bracing a box-couples and moves the first panel vibrations to the next. Along with thick enough cabinet material the proper amount of dampening (stuffing) materal seems to be the best choice depending on your design goals. Sub boxes are another story.
I have to agree alot of newer speakers drivers are over damped to a point of strangeling the musicality right out of them.

Good stuff, about damping and such. I am going to remove some of the fiberglass that I have in the cabinet and see if it makes a livlier presentaion. I think I overdid it, a bit. The cabinet does resonate and at high volume, the driver is vibrating 3 1/2" of fiberglass and 1 1/2" of plywood. I'd have to get out the cement mixer to completely deaden the beasts. What sound would I end up with having two crypts in my house?

FWIW, I consulted with the horniest guy I know about this and after a brief recuperative session, I feel better. It reminded me that there are a lot of different ways to get to the objective.:thmbsp:

 

[automojo]

I know I'm am learning a lot about horns/design as well.
Latley I have also drawn the conclusion that speakers are a lot like a musical instrument.
Aside from trying to get a fairly reasonabley flat frequency response-you have to work with and tune, not nessisarily eliminate some of the natural occuring dynamics of speakers and cabinets.

 

[westend]

I know I'm am learning a lot about horns/design as well.
Latley I have also drawn the conclusion that speakers are a lot like a musical instrument.
Aside from trying to get a fairly reasonabley flat frequency response-you have to work with and tune, not nessisarily eliminate some of the natural occuring dynamics of speakers and cabinets.

This is pretty close to my thinking on enclosures, regarding resonances. I did some research on material resonant speeds and frequencies when I was designing a turntable plinth. The metals were the fastest and most resonant, of course, copper and aluminum being close to the top of the list. Different species of wood also resonate at different frequency and amplitude, that's why we have Spruce topped acoustical guitars and not Walnut.

In my conversation with a local horn afficiando, it was mentioned,"a metal horn sounds like metal, a wood horn sounds like wood, and a plastic or fiberglass horn has it's own tone". This is probably the defining criteria fo me as I am not married to the 811 and might build some wood horns once the speakers are in the house and I can estimate better, the overall presentation.

I removed the foam and fertilizer bag from the horn rather quickly as I can't hear a bit of difference nor could a few others with better hearing. My Plum trees are thankful. I have no doubt that applying damping material to the exterior of the aluminum horn helps to eliminate resonance and that can't be a bad thing because of the material (aluminum). Since I am bandpassing the horn, it may be that any really bad resonance is not affecting the sound. If it is, it must be very minute.

A local Jazz lover stopped by last night with a few discs and I was a bit apprehensive about his thoughts about the speakers. I still have them in the garage and I know I can do a better job with level matching and improving the cabinets. A little Stan Getz, a couple of cigars, and libation brought forth his approval and relieved my anxiety. Listening this morning made me think that these are more balanced than I initially thought. This is probably psychoacoustics at work, lol.

 

[shawnra]

You know Lance it is kind of a type of providence that we were building our projects at the same time because I do not have a great knowledge of horn speakers but if I had not taken the path I did, I would have gone the route your on. I've always wanted to tackle something big and horn loaded. Those concentric drivers by Great Plains Audio really have caught my attention and I probably would have tried one of their designs. If I were to see your speakers in my everyday activities they would cause my head to swing so hard I'd probably get whiplash

It is too bad we live so far apart because I would love to hear our projects side by side with the same associated equipment. It would be a most interesting venture into a comparison of the best yesteryear had to offer (with a lot of modern thinking) and a good modern no compromise speaker. Good on ya Eh!

 

[Altec Best]

Lance do you have any kind of measuring equipment,software,etc...

This will be the easiest way to acheive your goals I think.Especially trying to find a pesky box resonance.And will help you acheive a flat response.I remember you inquiring about a souncard for measuring over at the Altec board with Bfish IIRC.


Regards ~ John

 

[westend]

You know Lance it is kind of a type of providence that we were building our projects at the same time because I do not have a great knowledge of horn speakers but if I had not taken the path I did, I would have gone the route your on. I've always wanted to tackle something big and horn loaded. Those concentric drivers by Great Plains Audio really have caught my attention and I probably would have tried one of their designs. If I were to see your speakers in my everyday activities they would cause my head to swing so hard I'd probably get whiplash

It is too bad we live so far apart because I would love to hear our projects side by side with the same associated equipment. It would be a most interesting venture into a comparison of the best yesteryear had to offer (with a lot of modern thinking) and a good modern no compromise speaker. Good on ya Eh!

My thougts, exactly reversed in your direction, I'd really like to build something with the Seas drivers. I heard another top-flight system, yesterday, and it was a different presentation than the Altec boxes, in some ways, much better. A guy has to get along with what he has and be grateful, I guess. Another couple of guys stopped by and they also gave a nod of approval, that's always a good sign. One of these guys was over 90 and had built the "Sweet Sixteen" columns, small world, DIY speaker builders.

Lance do you have any kind of measuring equipment,software,etc...

This will be the easiest way to acheive your goals I think.Especially trying to find a pesky box resonance.And will help you acheive a flat response.I remember you inquiring about a souncard for measuring over at the Altec board with Bfish IIRC.


Regards ~ John

Yeah, I definitely want to get onboard with measuring. I found a source for the Panasonic Electret condenser chips and S. Linkwitz has posted the microphone circuit information on his site.
Knowing me too well, I might just drop over to Guitar Center and pick up the whole pre-made package, though. They have the Behringer mics on sale, right now.
Did you get the Maudio connection box? The discussion on the Altec board is kind of fuzzy in my memory. There is a thread or a few in the "Speakers" section, here at AK about measuring and some of the learned guys discuss methods and gear to accomplish this.
No big hurry on measuring because it's best done outdoors, correct? The attached picture is what I woke up to, this morning.