AR Box and Woofer Sealing

[Analogman]

The subjective "slow return" test makes no sense to me from a practical view, (I'm a mechanic by trade).

Would not a slow return of the woofer's cone to it's rest position indicate a small unmetered leak?

Especially considering that not only the change induced in internal cabinet pressure combined with the spider and outer compliance's "memory" wanting things back at rest, it would seem you would want a rapid return? No?

Press on the outer surface of a tightly inflated balloon or tire and it returns almost immediately after the pressure is removed.

An automotive shock absorber returns slowly after being "compressed" but this return to rest or "static" orientation is metered internally.

I know on Jensen era "Advent" 10"s the voice coil cooling is accomplished via the fine mesh "dust cap". Aren't the old potted magnet 10"s cooled the same way? Even though their "dust cap" is not opaque?

I've spent many years working on the skill to properly seal things, both fluid and gaseous. I am confident my woofers have been well installed on all my projects, but I've yet had one require anywhere near a full second or more to return to rest when manipulated as prescribed.

Not doubting here, just wish to understand.

Please enlighten.

Regards,

Craig

[Analogman]

?

[RoyC]

The subjective "slow return" test makes no sense to me from a practical view, (I'm a mechanic by trade).

Would not a slow return of the woofer's cone to it's rest position indicate a small unmetered leak?

Especially considering that not only the change induced in internal cabinet pressure combined with the spider and outer compliance's "memory" wanting things back at rest, it would seem you would want a rapid return? No?

Please enlighten.

Regards,

Craig

Hi Craig,

The "slow woofer test" provides a general indication that an acoustic suspension (sometimes referred to as "air spring") woofer is properly installed. A "relatively" air tight cabinet is required for appropriate support and control of the very compliant woofer suspension. An acoustic suspension woofer would have less power handling capability and could be damaged if the cabinet is not tight enough. If the cabinet is too tight it can inhibit performance, as some leakage is required to allow the cone to move properly against the air inside the cabinet.

Some manufacturer's have expanded on this concept by designing speakers with more precisely controlled leakage (referred to as "aperiodic loading").

see http://diyaudioprojects.com/Technical/Aperiodic/

I attached Villchur's patent document. It goes into great detail on this subject.

Roy

Villchur_patent.pdf

[soundminded]

You are right. In a perfectly sealed enclosure the cone would return instantly...if there was no damping. The fiberglass creates an aerodynamic drag on the woofer causing it to have to work to pull or push air through the spaces between the fibers. This is the velocity related loss component in Newton's second law of motion that slows the woofer's motion down. Think of it as the difference between bouncing a car up and down with and without shock absorbers, the velocity related drag on the suspension. When the shock abosorbers are worn and no longer produce this drag, the car bounces back instantly and it even overshoots. The slow return demonstrates that the stuffing is doing its job.

A very small leak is desirable in an acoustic suspension system. The reason has been pointed out by Tom Tyson many times. He calls it the manometer effect. If the system were perfectly sealed, the air pressure inside when no voltage was applied would be the atmospheric pressure at the time of manufacure. Any change in barometric air pressure on the outside would cause the "neutral" position of the cone to become displaced from its central position in the magnetic field. Real world acoustic suspension speakers must have some mechanical restoring force. With a very slight leak, the pressure inside the cabinet can come into equilibrium with the barometric pressure on the outside wherever the speaker happens to be. Anything more than an infinitesmal leak though will eliminate the pneumatic effect the AS system is designed around.

[Analogman]

Thank you both, much.

How slow is "slow" then?

My tweeters and mids were left undisturbed; as installed by the factory.

I discarded the white foam gasket after several "in and outs" during the restoration/road test process

and opted for caulk.

I am as certain as one can be that the woofer's basket flange is well sealed against the plywood baffle.

I have double checked my surround job, I have an excellent seal.

Still, the cone returns almost immediately after being depressed.

Bass performance is superb; the only problem I am having now is locating and "fixing" all the damn vibrations and buzzing going on in my living room!

It's very rewarding to have recordings of an ACOUSTIC bass make things rattle and buzz, although a bit nerve racking to acclimate to so soon after a project of this nature (I keep thinking somethings wrong with my new friends).

Suggestions?

Thank you both, again,

Craig

[soundminded]

Loudspeaker systems which are installed in audio systems that have truely wide range, that is real system gain at very low frequencies present a whole host of problems systems with more limited low frequency capabilities don't exhibit. The rattling and buzzing of all loose objects in a room is only one of them. I've traced some of mne to the frame around screen windows, others to those decorative plastic inserts in windows that make them look like they are lots of small panes of glass instead of one large one. Another is acoustic feedback if you use a turntable. I had one cd player where my AR 9s routinely kicked the laser right off the track on some discs. A surprising number of CDs have low frequency rumble and other LF disturbances in the recordings. There are room resonances and where you sit can have a profoud effect on how much deep bass you hear. Generally, the same rules that apply for speaker placement also apply to listening position. Highest relative low bass levels are near room boundaries, the more you are near the louder the bass. Corners are the most, in the center is the least. A foot or two in a small room can make a big difference.

[RoyC]

How slow is "slow" then?

Craig

Craig,

In my experience, as long as your woofer returns more slowly than it would outside the cabinet, you are probably close enough to optimal for most listening levels. Don't worry about how long it takes to return...It varies with model and woofer.

I personally find a woofer that returns a bit more quickly to sound better than one that returns too slowly.

One of the most often overlooked variables is the replacement foam surround. Some are very porous, and to date, I am not aware of any substance that can be used on them that will make them less porous without making them too stiff. Other possiblities include all driver gaskets, terminal boards, and cabinet joints. The pots allow some leakage as well.

If your speakers sound good at your typical listening levels, I would not lose sleep over the woofer return issue.

Roy

[Pete B]

Hi Craig,

There are actually two effects going on here. First, lets consider a closed box

speaker with a perfect seal, it will have a closed box resonant frequency (Fc

typically 30 to 80 Hz) as a result of the cone mass and the combined air and

suspension springs. If you tap this cone it will return at a rate related to Fc,

typically a small fraction of a second - fast. If you push it in and hold it, it will

also return fast since we are assuming a perfect seal where no air leaks out.

Now, consider a very small leak, tap the cone and it will return fast just as in

the perfectly sealed case. Push it in gently, hold, and the pressure will slowly

equalize inside the box back to atmospheric at a rate that is proportional to the

leak. Release, and the cone will return slowly at a rate also proportional to the

leak. We would be measuring the time constant of the leak, not Fc in this case.

Resistive losses due to damping simply alter the shape of the resonance at Fc,

and can control overshoot and ringing in the same way as a shock on a car.

Is the story here on the board about how AR intentionally added a small leak?

[johnieo]

How slow is "slow" then?Craig

Craig:

Pete is correct. Gas flow impedance you are encountering has nothing to do with the fiberglass stuffing--stuffing determines the acoustic impedance (the ratio of sound pressure to sound velocity), which determines the acoustic damping at cabinet resonance.

The flow impedance you are dealing with when depressing, holding, and then releasing the cone is air flow resistance (the ratio of pressure difference to flow) of the air flowing in and out of the cabinet when you depress and release the cone. The gas flow impedance of air flowing through the fiberglass is insignificant by comparison.

An AR-3a cabinet has a volume of 43 liters. Assume that depressing and holding the 12-in woofer cone expels 43 cc of air out through a small leak and on release the 12-in woofer cone returns in about 1 second. From this we find a leak flow of ~43 (atm-cc/sec) entering the cabinet for about a second, when releasing the woofer. Next assume the leak is through a round hole, 3/4-inch long, with a pressure difference of 0.001 atm between inside and outside of the cabinet. From this with some math, we find the leak is ~1.8 milimeters in diameter! That kind of leak is easily "distributed" through the pores of the surround and among the 2 potentiometer shafts and 3 terminal screws. The inside of the Masonite crossover board is the rough side; it cannot make a tight seal to anything, even with a rubber gasket. Many of the surrounds are so porous one can breathe through them easily. Cloth surrounds have always yielded longer recovery times than foam. The time constants we all quote (1-to-2 s.) for release of the cone relate to the AR-12 inch woofer. I have no idea what the numbers are for smaller woofers.

As has been pointed out many times by the designers and and other responders, a small leak is necessary, and it needs only to be small enough so that it is not evident at the lowest bass frequency. It takes 0.0125 seconds for a 20-Hz note to move the cone from rest to its maxumum excursion, so one second is "not a leak" on that time scale.

Cheers,

[Analogman]

Understood.

So, a woofer cone that returns almost instantly could mean:

1. A system that has a near perfect pneumatic seal.

OR

2. A system possessing a substantial leak to ambient air pressure and at the same time a very effective, (low/stiff), mechanical compliance.

All speaking to the rate of "metering" a "leak" is subjected to. (the size of the pathway to ambient air pressure)

This was the basis for my question. The return rate "test" just seemed purely anecdotal to me, as so many other variables could be at play as those of you have so graciously taken the time to address.

As for the box stuffing: you can fill a tire and rim assembly exactly half full (volume) of sand or water, then inflate it with air to 28psi. That 28psi remains constant regardless, and would escape at the same rate as with a "clean" tire if you punched a hole in it with an ice pick (keeping the escape hole clear of your foreign material). Only the time required to achieve equilibrium with ambient air pressure would be shorter, as sand or water was occupying some of the tire's volume. I can't imagine the type of material one uses to stuff a box could possibly alter the physics of a compressed gas, in this case "air", other than by volume, as it pertains simply to pressure. I do agree that stuffing material can alter sonic qualities, but more akin to the way the type and thickness of finish will affect a wooden instrument. I would think it more relevant to resonant frequencies than anything else.

Understandably, changes in internal volume will have a definite affect of sound and response, but I was seeking clarity on a mechanical point.

Pardon my analogies and thank you for indulging me; I'm a mathematics dumb ass.

Sincere regards,

Craig

[johnieo]

This was the basis for my question. The return rate "test" just seemed purely anecdotal to me, as so many other variables could be at play as those of you have so graciously taken the time to address.

I was seeking clarity on a mechanical point.

Craig

Craig: The stuffing does not fill much of the volume. In a Fiberglass-filled cabinet, the air occupies 99.5% of the volume. In a polyester-stuffed cabinet, it occupies 93.5%. (The polyester is larger diameter than fiberglass (23 um compared to 2-5 um) more is needed as it is less efficient at absorbing/releasing heat and in affecting the acoutstic impedance. So as your anaogy suggests, it doesnt have much to do with leak response rates.

The bottom line is that if you depress a TWELVE-IN diameter AR cone to its maximum excursion--about 1/2 in -- hold it depressed for a minute, then release it suddenly, it should take ~second or so to equilibrate. This is not an anectode! It was published by Roy Allison, the speaker designer in the mid-1970s as the way to determine if the speaker is sealed properly! If it pops back instantly then you have either an extremely porous surround, or a rather large hole. One way of examining the porosity of your surround is to spray it with a water mister - like used for ironing clothes. The water will seal the surround tightly and prevent air from permeating it for a few minutes until it evaporates. Then try to depress all the way to the bottom, hold, and release. If you see a big difference before/after, then you have an extremely porous surround. I know Roy C has seen big difference in foam porosity, but do not know if he related that to bass extension.

Cheers,

[RoyC]

I know Roy C has seen big difference in foam porosity, but do not know if he related that to bass extension.

Cheers,

I have not experienced big differences...nor have I experienced (or measured) negative effects from woofers that return a bit more quickly than they "should". The lowest octaves at high volume are likely to be where any negative effects, if any, are noticed. Going back to the aperiodic design theory...The cabinet "leak" is such that there is less resistance to woofer movement at lower input levels, but progressively more support and control due to cabinet air pressure at higher levels. When this type of design was first promoted, it was an attempt to more precisely define and induce the amount of optimum leakage in an otherwise acoustic suspension system through the use of small cabinet holes, or devices known as "Variovents".

I first discovered the surround foam porosity issue when I was unable to get, what I believed to be at the time, a satisfactory "slow woofer return" result with the AB Tech/Tonegen AR 12" replacement woofer. It has a much more porous surround than the 5/8" replacement surround typically used to refoam the older, more compliant woofers. It also has a stiffer suspension. There is no way this woofer, in its stock form, could be made to meet the 1+ second rule. After unsuccessfully experimenting with sealants on a number of foam surrounds for various AR woofers, I found less porous surrounds to try. In the end I confirmed high compliance (thin and soft) is the most important attribute an AR surround can have. This and a "somewhat" slower woofer return than when outside the cabinet should provide satisfactory performance. If you (carefully) push or tap the woofer more quickly and harder you should feel resistance. If not, more sealing is definitely needed. In any case a stop watch is not, IMO.

Some AR-4x woofers cannot be made to slow down very much at all due to a screen mesh covering the magnet and the screen dust cap (see pics). There is leakage past the voice coil and through the dust cap. It is part of the design. Glopping sealant on the typically porous cloth surrounds of these woofers won't slow them down and will compromise performance.

As an aside, my latest adventures have been revolving around Avid speakers of the 1970's. After 30+ years that manufacturer's original foam gasketed, soft *rubber* surround woofers still easily pass the slow woofer return test...and sound great.

BTW, a woofer in a totally sealed enclosure is significantly harder to push, and pretty easy to identify. It is rarely the cause of a return deemed to be "too fast" simply because the old cabinets are difficult to seal to that degree.

Roy

[Mexicomike]

When I recappped my LSTs I disgarded the foam woofer gasket in favor of the duct seal material used by AR on earlier speakers. There was a noticeable difference in the woofer return rate between the two, with the duct seal yielding a slower rate. The gasket's return rate was only slightly slower than the return in free air. Which was "better" freq response wise, I have no idea but the return with duct seal seemed more "AR-like, duplicating the return rate on my AR3As!

[Analogman]

I have not experienced big differences...nor have I experienced (or measured) negative effects from woofers that return a bit more quickly than they "should". The lowest octaves at high volume are likely to be where any negative effects, if any, are noticed. Going back to the aperiodic design theory...The cabinet "leak" is such that there is less resistance to woofer movement at lower input levels, but progressively more support and control due to cabinet air pressure at higher levels. When this type of design was first promoted, it was an attempt to more precisely define and induce the amount of optimum leakage in an otherwise acoustic suspension system through the use of small cabinet holes, or devices known as "Variovents".

I first discovered the surround foam porosity issue when I was unable to get, what I believed to be at the time, a satisfactory "slow woofer return" result with the AB Tech/Tonegen AR 12" replacement woofer. It has a much more porous surround than the 5/8" replacement surround typically used to refoam the older, more compliant woofers. It also has a stiffer suspension. There is no way this woofer, in its stock form, could be made to meet the 1+ second rule. After unsuccessfully experimenting with sealants on a number of foam surrounds for various AR woofers, I found less porous surrounds to try. In the end I confirmed high compliance (thin and soft) is the most important attribute an AR surround can have. This and a "somewhat" slower woofer return than when outside the cabinet should provide satisfactory performance. If you (carefully) push or tap the woofer more quickly and harder you should feel resistance. If not, more sealing is definitely needed. In any case a stop watch is not, IMO.

Some AR-4x woofers cannot be made to slow down very much at all due to a screen mesh covering the magnet and the screen dust cap (see pics). There is leakage past the voice coil and through the dust cap. It is part of the design. Glopping sealant on the typically porous cloth surrounds of these woofers won't slow them down and will compromise performance.

As an aside, my latest adventures have been revolving around Avid speakers of the 1970's. After 30+ years that manufacturer's original foam gasketed, soft *rubber* surround woofers still easily pass the slow woofer return test...and sound great.

BTW, a woofer in a totally sealed enclosure is significantly harder to push, and pretty easy to identify. It is rarely the cause of a return deemed to be "too fast" simply because the old cabinets are difficult to seal to that degree.

Roy

Thanks Roy.

I think the flaw has been with my methodology, not holding the cone in long enough; I'm going to try it again and hold the cone "in" longer to allow ample time for the pressures to equalize.

If the results are the same, then I'm not going to fret over it any longer.

Regards,

Craig

[Analogman]

When I recappped my LSTs I disgarded the foam woofer gasket in favor of the duct seal material used by AR on earlier speakers. There was a noticeable difference in the woofer return rate between the two, with the duct seal yielding a slower rate. The gasket's return rate was only slightly slower than the return in free air. Which was "better" freq response wise, I have no idea but the return with duct seal seemed more "AR-like, duplicating the return rate on my AR3As!

Thank you!

Craig

[soundminded]

Craig:

Pete is correct. Gas flow impedance you are encountering has nothing to do with the fiberglass stuffing--stuffing determines the acoustic impedance (the ratio of sound pressure to sound velocity), which determines the acoustic damping at cabinet resonance.

The flow impedance you are dealing with when depressing, holding, and then releasing the cone is air flow resistance (the ratio of pressure difference to flow) of the air flowing in and out of the cabinet when you depress and release the cone. The gas flow impedance of air flowing through the fiberglass is insignificant by comparison.

An AR-3a cabinet has a volume of 43 liters. Assume that depressing and holding the 12-in woofer cone expels 43 cc of air out through a small leak and on release the 12-in woofer cone returns in about 1 second. From this we find a leak flow of ~43 (atm-cc/sec) entering the cabinet for about a second, when releasing the woofer. Next assume the leak is through a round hole, 3/4-inch long, with a pressure difference of 0.001 atm between inside and outside of the cabinet. From this with some math, we find the leak is ~1.8 milimeters in diameter! That kind of leak is easily "distributed" through the pores of the surround and among the 2 potentiometer shafts and 3 terminal screws. The inside of the Masonite crossover board is the rough side; it cannot make a tight seal to anything, even with a rubber gasket. Many of the surrounds are so porous one can breathe through them easily. Cloth surrounds have always yielded longer recovery times than foam. The time constants we all quote (1-to-2 s.) for release of the cone relate to the AR-12 inch woofer. I have no idea what the numbers are for smaller woofers.

As has been pointed out many times by the designers and and other responders, a small leak is necessary, and it needs only to be small enough so that it is not evident at the lowest bass frequency. It takes 0.0125 seconds for a 20-Hz note to move the cone from rest to its maxumum excursion, so one second is "not a leak" on that time scale.

Cheers,

I have to disagree. If the driver were truely a purely acoustic suspension driver, if it had no enclosure and you pushed in the cone it would not return at all. It would not have any mechanical restoring force to cause it to return. The early AR1 and AR3 drivers came closest to this. Later AR 12" drivers had some mechanical restoring force for practical reasons, to restore the cone to a "neutral" position regardless of the barometric pressure outside the box. If the box were perfectly sealed and had no fiberglass, pushing it in and releasing it no matter how long it was pushed in for would cause it to return quickly as you get when you push in a baloon. But when there is fiberglass inside and you depress the cone, you compress the air between the back of the cone and the fiberglass. If you release it then, the cone will return instantly. But if you keep it depressed, the increased air pressure will push air molecules through the glass fibers slowly equalizing the increased pressure inside the box until it is uniform. Then when you release it, that same resistance to air flow between the fibers will cause it to require time for those molecules trapped deep inside the fiberglass under pressure to squeeze through the fibers and push the cone back out equalizing the pressure against the exterior. If there is a small leak, say a pinhole, and you push the cone in, it will take time for the air to squeeze through it, the larger the leak and nearer to the cone, the faster air will flow. When you let it go, the mechanical restoring force of the driver will restore the cone to its neutral point, the larger the leak the faster this will happen.

The thermodynamic model is virtually useless in understanding this. Thermodynamics is the study of the relationship between work and heat. It actually is about comparisons between relatively stable end states and would be better called thermostatics. It is true that the cone does PV work and that the frictional losses of the air being squeezed through the fibers is converted to heat, that is what friction is the conversion of work into heat. But that is only a very small fraction of the electrical work the amplifier does. Most is lost to heat though resisitive heating of the voice coil, the rest through mechanical frictional losses in the cone's suspension. If thermodyanmics could tell us about the actual motion of the cone, we wouldn't need Newton. Villchur is to be credited for getting the right answer...even if he didn't fully or accurately understand the physics explaining the reason why it was right.

[Guest rek 2-3-4]

OK, let me stir this one again.

My AR-3a's woofers have the 1-2 second return from compression thing going on.

Neither my AR-2ax pair nor my AR-4x pair have any delay at all.

Should they? If not, why not?

Do I have a problem with them?

Just curious.

[kkantor]

Here's my opinion, for what it is worth:

- I don't think "instant" return particularly indicates a problem with your 4x. It's really difficult to eyeball smaller woofers and draw meaningful conclusion about cabinet leakage. If the speaker is sounding right, it likely is just fine.

- You probably should be able to see at least some return delay on the 2ax, after keeping the woofer pressed in for 20 or 30 seconds. If you are sure you don't, it might be a good idea to check more rigorously for air leaks. This would involve using a very low frequency sine wave, a stethoscope and a candle. (I'm assuming you are over the age of consent...)

-k

www.kenkantor.com

www.ztamplifiers.com

OK, let me stir this one again.

My AR-3a's woofers have the 1-2 second return from compression thing going on.

Neither my AR-2ax pair nor my AR-4x pair have any delay at all.

Should they? If not, why not?

Do I have a problem with them?

Just curious.

[Guest rek 2-3-4]

After giving the Permatex High Tack Gasket Sealent a good bit of thought, I decided to take a different route.

I contacted Larry at Vintage AR. Turns out he has a different surround sealant he felt was closer to the AR original than the Permatex stuff. About $5.00 plus shipping.

It's black and very viscous. However, it went on the 3a and 4x woofers without a hitch.

I believe I can hear an improvement in bass, mostly with the 3a's. The floor now vibrates on various types of music, especially organ (I'm an E. Power Biggs fan), which was not occurring before. I think the "bounce back" is a bit slower too. I don't own a stop watch.

Anyway, it is an alternative to the automotive product.

[Analogman]

After giving the Permatex High Tack Gasket Sealent a good bit of thought, I decided to take a different route.

I contacted Larry at Vintage AR. Turns out he has a different surround sealant he felt was closer to the AR original than the Permatex stuff. About $5.00 plus shipping.

It's black and very viscous. However, it went on the 3a and 4x woofers without a hitch.

I believe I can hear an improvement in bass, mostly with the 3a's. The floor now vibrates on various types of music, especially organ (I'm an E. Power Biggs fan), which was not occurring before. I think the "bounce back" is a bit slower too. I don't own a stop watch.

Anyway, it is an alternative to the automotive product.

As is "Tums" and prescription drugs to baking soda.

Be careful now where you put your speakers. All of the black surround shit I've seen runs and drips over time if it's hot in the room, or in sunlight. I'm in the automotive trade, and the suggested product discussed here is very tolerant of heat, (and cold, remains stable).

And remember, nearly all material technology found in the automotive industry is "trickle down" from the vast "military/industrial" complex.

I think the "New England" speaker builders took "off the shelf" engineering and elevated it to an Art form. That's one reason it's often so difficult to get accurate information regarding such.

From what little experience I have had with "AR" there's one thing I've noted for sure. They were consistently inconsistent. Maybe that's why they sound so well; not so much hair splitting.

Individuals here that have already handily won my faith have endorsed a "Permatex" product. (better, a proprietary material packaged and sold under the "Permatex" moniker).

That's all I need to know.

Even "3M"'s cyanoacrylate is made in Japan, it all is, except for the Chinese crap that's showing up at dollar stores now.

I remember when Larry was just starting his little business; I outbid him in an ePay auction for a pair of cast frame "AR" 10"s.

Now, from what I can see from his store on-line, he deals mainly in knock-off and repro stuff. (WAY overpriced, IN MY OPINION).

I'll stick with the camp that has made the effort to do some meaningful research/experimentation.

Regards,

Craig

[Guest rek 2-3-4]

As is "Tums" and prescription drugs to baking soda.

Be careful now where you put your speakers. All of the black surround shit I've seen runs and drips over time if it's hot in the room, or in sunlight. I'm in the automotive trade, and the suggested product discussed here is very tolerant of heat, (and cold, remains stable).

And remember, nearly all material technology found in the automotive industry is "trickle down" from the vast "military/industrial" complex.

I think the "New England" speaker builders took "off the shelf" engineering and elevated it to an Art form. That's one reason it's often so difficult to get accurate information regarding such.

From what little experience I have had with "AR" there's one thing I've noted for sure. They were consistently inconsistent. Maybe that's why they sound so well; not so much hair splitting.

Individuals here that have already handily won my faith have endorsed a "Permatex" product. (better, a proprietary material packaged and sold under the "Permatex" moniker).

That's all I need to know.

Even "3M"'s cyanoacrylate is made in Japan, it all is, except for the Chinese crap that's showing up at dollar stores now.

I remember when Larry was just starting his little business; I outbid him in an ePay auction for a pair of cast frame "AR" 10"s.

Now, from what I can see from his store on-line, he deals mainly in knock-off and repro stuff. (WAY overpriced, IN MY OPINION).

I'll stick with the camp that has made the effort to do some meaningful research/experimentation.

Regards,

Craig

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Ya know, Craig, I had no idea that The Classic Speaker Pages Forum is actually a gospel and that any alternate views or comments are viewed as heresy. I am really mystified by your tirade and the deprecating tone in your response.

a. My speakers reside in a climate controlled room not in an incinerator room or as the nexus of a display of mirrors. I don't think I'm going to be encountering a "melting issue".

b. "trickle down" "military-industrial complex". What the hell is that about?

c. ARs are inconsistent? I don't care. Mine work fine for me.

d. "3M"'s cyanoacrylate". Never used it, never heard of it, doesn't matter to me one whit.

e. My experiences with Larry over the past couple of years have been just great. I don't think his items are overpriced, unless you're comparing them to Goodwill or The Salvation Army. The items I've purchased from him have installed easily and worked well. I trust him more than a rude obsessive-compulsive like you.

So, I will not darken this forum's doorstep again. You can continue fixing stuff that isn't broken and try to do better than the engineers who originally designed the equipment. Have fun!

[RoyC]

Larry is a good businessman and a nice guy...and lives 10 minutes from me. We have exchanged many parts and ideas for several years now. A few months ago he brought me some "new" woofers that AB Tech was trying to pass off as AR 12 inch replacements for testing. They failed miserably, and he returned them to ABT :-)). As always, we spent hours talking about AR parts and restoration solutions.

He is very aware that his primary "customers" are not the hardcore hobbyists that reside here, and has used more than a few of our findings to enhance his business. Some of his items are excellent and unique, such as his reproduction AR badges and stainless steel knurled terminal screws. Others are easily obtainable at less cost, such as his putty and level controls, which are sourced from Home Depot and Madisound/Parts Express respectively. With AB Tech fading, he is as dependent as we are on thrift stores, estate sales, and Ebay for many of his replacement parts. I am aware of his black surround sealant, and we have been intending to compare some notes on such things. If his sealant is the same stuff he was using awhile back, it is thicker than the Permatex, and cures more stiffly. BTW, neither of us have been able to come up with a suitable sealant to replace the butyl compound AR used on foam surrounds.

The casual (many times confused) reader of this forum, or someone who just wants to "fix" a pair of AR speakers will likely do fine purchasing the required items from Larry, but there is much more detailed information and assistance to be obtained from this website for the hardcore AR hobbyist, or for a person desiring to restore AR speakers as "authentically" as possible.

Roy

[Analogman]

Larry is a good businessman and a nice guy...and lives 10 minutes from me. We have exchanged many parts and ideas for several years now. A few months ago he brought me some "new" woofers that AB Tech was trying to pass off as AR 12 inch replacements for testing. They failed miserably, and he returned them to ABT :-)). As always, we spent hours talking about AR parts and restoration solutions.

He is very aware that his primary "customers" are not the hardcore hobbyists that reside here, and has used more than a few of our findings to enhance his business. Some of his items are excellent and unique, such as his reproduction AR badges and stainless steel knurled terminal screws. Others are easily obtainable at less cost, such as his putty and level controls, which are sourced from Home Depot and Madisound/Parts Express respectively. With AB Tech fading, he is as dependent as we are on thrift stores, estate sales, and Ebay for many of his replacement parts. I am aware of his black surround sealant, and we have been intending to compare some notes on such things. If his sealant is the same stuff he was using awhile back, it is thicker than the Permatex, and cures more stiffly. BTW, neither of us have been able to come up with a suitable sealant to replace the butyl compound AR used on foam surrounds.

The casual (many times confused) reader of this forum, or someone who just wants to "fix" a pair of AR speakers will likely do fine purchasing the required items from Larry, but there is much more detailed information and assistance to be obtained from this website for the hardcore AR hobbyist, or for a person desiring to restore AR speakers as "authentically" as possible.

Roy

Thank you, Roy.

Craig