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New Mid Range replacement


DavidR
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About a year ago I contacted Midwest Speakers and asked if they had a midrange replacement. They said they didn't and was wondering if there was an interest. I hooked them up with a couple of links to threads discussing the various replacements that were available and I told them their tweeter was the most accurate copy out there IMO. They had a 200044 mid for developing a copy and decided to move forward with it. They said it would take a year or so.

tweeter link >   https://www.midwestspeakerrepair.com/shop/home-audio/tweeters/dome/mw-audio-mt-4121-75-inch-dome-tweeter/

Well today I looked up the email regarding this topic and asked if they had any developments. Positive news arrived quickly. They wrote back with this:

"Hi, 

They were supposed to be here about 3 weeks ago, but our shipment has been stuck in the port in CA.  Hopefully we will see it in a few weeks."

They will retail for $114.95 each + shipping. I just might buy one or two and be the guinea pig.

SPECS: Impedance: 4 ohms
Re: 3.2 ohms
SPL 85 dB
Freq Range: 450 Hz- 10K
Net Weight: 4.17 lbs

 

 

In the attached speakers is a picture of the 200044 (on the left in all pics) and the initial copy they sent. 

 

 

DSCF7717.JPG

DSCF7718.JPG

DSCF7719.JPG

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5 hours ago, DavidR said:

Buzzing, muted sound, distortion are a few symptoms

Heya David,

One of my midrange speakers on my AR-11 just started doing this the other day. Can this be repaired? Or do I need to start the hunt for a replacement? (probably two I'm guessing) 

Cheers.

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37 minutes ago, Earthnz said:

Heya David,

One of my midrange speakers on my AR-11 just started doing this the other day. Can this be repaired? Or do I need to start the hunt for a replacement? (probably two I'm guessing) 

Cheers.

Some of the earlier mids can be repaired I believe. Those with more knowledge, Like RoyC, would know. I know of no one who has repaired a Series 9 mid: p/n 200028 and 200032.

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8 hours ago, DavidR said:

Some of the earlier mids can be repaired I believe. Those with more knowledge, Like RoyC, would know. I know of no one who has repaired a Series 9 mid: p/n 200028 and 200032.

Thanks for the reply David. Much appreciated 👍

 

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On 7/23/2021 at 11:15 PM, DavidR said:

But do they sound like the originals?

But they have the same aesthetics as the originals ... Should they have a treatment on the dome and surrounding suspension to standardize the original ?! Performed by enthusiast at a later time, after purchase?

They are however appreciable, adequate replicas to the original.

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Giorgio AR, The person I've been dealing with at MidWest Speakers mentioned the dome color as odd. This was a proto-type and was tested for SQ to the original prior to getting approval to move forward. He is not sure if the production copies will be the same. I think they nailed the look and magnet structure. Now its time to check how they sound.

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After the first 2 iterations of the AR-3 mid, all versions of this AR mid, beginning with the AR-3a, share the same basic construction and electrical characteristics. The various AR-9xx/AR-58 versions are essentially the back-wired AR3a/AR-11/10pi midrange with a plastic ring glued to the front, and there is a far greater call for a replacement mid without the ring. Midwest will sell more of these replacements if the plastic ring is offered as an adhesive back option, or if it is easily removable.

Roy

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55 minutes ago, RoyC said:

..............and there is a far greater call for a replacement mid without the ring. Midwest will sell more of these replacements if the plastic ring is offered as an adhesive back option, or if it is easily removable.

Why is that?

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30 minutes ago, DavidR said:

Why is that?

A guess.  At least two reasons:

1. The Market is larger for the Mid without the " Semi Horn" and a non AR9 load of ferro fluid.

2, Technical reasons relating to design of earlier wider dispersion speaker systems.

image.png.a49ba04cfc323e384e383d1eba17b74d.png

but it may not matter if the lower limit frequency response is 650Hz because the low crossover frequency of a classic era domed mid is 525hz with a resonance frequency of 400hz.

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I believe Aadams has provided the best answer(s), so I will just add some thoughts.

Based on my experience with "Vintage_AR" and my own work, the market for the original, non-semi-horn version appears to be much greater. Quite frankly, there really doesn't seem to be much demand for the later AR-9xx version. I'm sure it has to do with the popularity of each model and the era of manufacture. The AR-9 series and the 58 may be popular in some circles, but the "classic" earlier models are where most of the parts are going. 

The last iteration of the AR-3 was equipped with the 3a type of mid. (This mid can also be used in earlier 3's.) The back-wired version used in later 3a's and AR-11 can also be converted for the earlier front-wired models. The AR-9xx/58 "semi-horn" version of the mid simply does not work very well with the dispersion and tonal characteristics of earlier AR models, unless the ring is removed. We have actually removed the rings from more than a few of the later style mids for AR-3a restorations in the past few years

Midwest's replacement AR-11 style tweeter with its fully exposed dome works well as a decent replacement for the semi-recessed dome of the AR-9 series, and I believe an AR-3a/11 style bare-dome mid could also work reasonably well, especially if the original plastic semi-horn ring is re-used.

I noticed mention of the Simply Speakers replacement mid. It isn't bad in a pinch if used in pairs, but the dome and magnet are a bit smaller. It is somewhat less sensitive than the original and has higher Fs, probably making it more suitable for later AR models. I seem to recall the rear terminals being positioned differently, requiring some minor cabinet hole modification. The rings and metal screens of the original AR mids do not fit on these mids.

Roy

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1 hour ago, RoyC said:

I believe Aadams has providd the best answer(s), so I will just add some thoughts.

Based on my experience with "Vintage_AR" and my own work, the market for the original, non-semi-horn version appears to be much greater. Quite frankly, there really doesn't seem to be much demand for the later AR-9xx version. I'm sure it has to do with the popularity of each model and the era of manufacture. The AR-9 series and the 58 may be popular in some circles, but the "classic" earlier models are where most of the parts are going. 

The last iteration of the AR-3 was equipped with the 3a type of mid. (This mid can also be used in earlier 3's.) The back-wired version used in later 3a's and AR-11 can also be converted for the earlier front-wired models. The AR-9xx/58 "semi-horn" version of the mid simply does not work very well with the dispersion and tonal characteristics of earlier AR models, unless the ring is removed. We have actually removed the rings from more than a few of the later style mids for AR-3a restorations in the past few years

Midwest's replacement AR-11 style tweeter with its fully exposed dome works well as a decent replacement for the semi-recessed dome of the AR-9 series, and I believe an AR-3a/11 style bare-dome mid could also work reasonably well, especially if the original plastic semi-horn ring is re-used.

I noticed mention of the Simply Speakers replacement mid. It isn't bad in a pinch if used in pairs, but the dome and magnet are a bit smaller. It is somewhat less sensitive than the original and has higher Fs, probably making it more suitable for later AR models. I seem to recall the rear terminals being positioned differently, requiring some minor cabinet hole modification. The rings and metal screens of the original AR mids do not fit on these mids.

Roy

Thanks for that information Roy, especially about the rings and screens from the AR-11 not being able to fit on the simply speakers midrange replacement. 

Are AR-11 midrange speakers repairable? One of mine has started to distort and become quite muted compared to the other. I live in New Zealand so AR spares is non existent here sadly, and ebay charges a fortune to ship to here (sometimes more than the brought item!) 

Cheers! 

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MidWest set out to make a copy of the 200044 mid. I think they nailed the appearance.

I have no 'classic' era AR speakers (yet) but have several Teledyne models. At some point even the drivers that have been parted for sale out will fail. It might be that the parts are going for the 'classic' models because they are older; the Teledyne are right behind.

If you contact Joe at MidWest and ask if they could make a run without the horn they might do it.

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Teledyne acquired AR in 1967 and owned it for the last eight or nine years of the "classic" period. The AR-3a, 5, LST 1/2 and the 10pi and 11 that would take a hornless dome mid are all "Teledyne models."

If I was making these, I'd lower the bottom end to reach down into the 500Hz range and make it possible to mount either the horn or the ring and screen to the front plate to create a "universal replacement."

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5 hours ago, genek said:

Teledyne acquired AR in 1967 and owned it for the last eight or nine years of the "classic" period. The AR-3a, 5, LST 1/2 and the 10pi and 11 that would take a hornless dome mid are all "Teledyne models."

If I was making these, I'd lower the bottom end to reach down into the 500Hz range and make it possible to mount either the horn or the ring and screen to the front plate to create a "universal replacement."

I agree, Gene. Unless the ring can be removed, Midwest may be missing an opportunity. I honestly do not believe there is ever going to be a significant demand for the semi-horn version of this mid.

Some other tidbits:

-The 200044 mid was the mid used in the AR-58 and has no damping material under the dome. The 200027 and 200032 and earlier, have a large amount of fiberglass under the dome, so above and beyond any ferrofluid placement differences, there is a response difference between them. After seeing the Midwest photo posted by David, I wonder how it will compare. Is that a plastic dome? Is there any damping material under it?

-AR sold a bare dome, back-wired version of the mid for use in the first iteration of the Cello Amati.

-The last high quality replacement was manufactured by Tonegen in the late 80's/early 90's and sold by AB Tech. It was used in the AR-3a Limited, and obviously did not have the plastic ring.

Earthnz: The usual failure point of the AR-11 mid (and most other AR high/mid frequency drivers) is breakage of a voice coil lead at the dome. I can often repair the early AR-3 mids by completely removing the dome, not so with the later cloth dome found in the last AR-3, 3a, onward.

Roy

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Roy, I downloaded the picture of the 044-copy and it does appear to be either plastic or a coating. I can clearly see fabric thru the dome. If they asked the Chinese for an exact copy I'm guessing that is what they got.

I believe AR was sending out the 044 driver as a replacement for failed 200028 UMRs as I know someone who has a pair of 9s with those drivers. I have no idea how they compare.

Perhaps you or someone with the knowledge of what you actually think would work better for the AR Community should contact Joe at MidWest and request those changes. It can't hurt. I am willing to buy one and swap it out with a UMR from my AR9, 90 and mid from the 91 and see how they compare.

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I ordered one of these new midrange copies of the 044 mid/UMR and a pair of their tweeters that I'm using in my AR10Pi. The dome is in fact a silk fabric dome with a clear coating. The coating is slightly tacky. I was unable to tell if there is any damping material below the dome. The mid/UMR has a free air resonance of 400Hz.

Today I got around to installing one tweeter and the UMR into my AR90s. The tweeter sounded identical in tone to the original 200029 tweeter but has slightly more output/volume associated with it. I found it easier to hear cymbals and other high Hz music signals.

The UMR also sounded like the original but I found it to be a bit clearer/cleaner than the 200028 UMRs which I find can sound honky at times. Could this be from drying ferrofluid or just a difference in the drives, I don't know. What I think is that these drivers, which are drop-in replacements, are quite suitable to replace the originals. Its only a matter of time before all the originals are dead or muted from dried ferrofluid. With nobody able to rebuild the originals to near factory specs I see no other solution at this point.

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The MidWest copy of the 044 mid is glossy black with the clear dome. They are exact copies right down to the holes and the magnet structure.

Why they didn't use a black coating on the dome is beyond me.

The tweeters resemble the older style found in speakers like the AR11 and 10Pi. The back is enclosed covering the magnet structure.

Both are drop in ready.

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6 hours ago, DavidR said:

The MidWest copy of the 044 mid is glossy black with the clear dome. They are exact copies right down to the holes and the magnet structure.

Why they didn't use a black coating on the dome is beyond me.

Thanks for the update, David.  Any idea how difficult it might be to remove the plastic ring?

Roy

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