I'm afraid it has happened?

[RoyC]

49 minutes ago, harry398 said:

well......any results???

Harry,

It may be a couple of weeks before I will get to see the one purchased by Larry/Vintage AR. 

Roy

[harry398]

aha, ok.

 

Latham eh?   I had a delivery in Mechanicville a few weeks back.......drove right past your exit on 87.   nice area up there!

 

[RoyC]

I finally had a chance to examine the new AR replacement tweeter sold by Midwest Speaker Repair.  Larry/Vintage AR provided the Midwest tweeter and an original (black dome) AR-11 tweeter, and I had an AR-9 tweeter on hand for comparison.

The construction of the new tweeter is very impressive, and at least as good as the original AR tweeters. The integrated faceplate/magnet cup is the same as the AR tweeters, but it is made of aluminum vs the plastic of the originals. A convenient feature vs either original tweeter are the recessed, gold plated terminals, making it a simple drop-in fit for any AR dome tweeter cabinet hole from the AR-3 (see photo below) through the AR-9x series into the 80's. The new tweeter is otherwise physically identical to the black dome AR-11/10pi/12 tweeter.  

Other observations:
-DCR of the two AR tweeters measured 3.3 ohms vs 3.7 ohms for the Midwest tweeter. (The MW tweeter is also available in an 8 ohm version.)
-The cloth domes of all three tweeters appear to be identical, including the dome shaped piece of hard material just underneath each dome (based on past dissections, this material is wood in the AR tweeters). The AR 9 series tweeter dome is recessed in the faceplate, but is otherwise identical.
-All tweeters weigh 1.5 lbs+/-. Magnet size is identical.
-No measurement equipment was used, but the new tweeter subjectively has very similar tonal qualities to that of both original tweeters. It is, however, slightly more sensitive.

-I quickly dropped the tweeter into an AR-3a and believe a larger parallel coil than the .05mh coil used with the HiVi tweeter will be needed to properly integrate it...but it sounds very promising. One downside is the front covering of the new tweeter would have to be cut to access the leads for front-wiring.

-It may serve as a very easy tweeter replacement for the AR-11, 10pi, 12 (8 ohm version), and AR-9x series models with no crossover adjustments (for most people) when satisfactory originals are not available.
-The Midwest tweeter is head and shoulders above any AR 3/4" general replacement tweeter I have seen since the very early 90's when AB Tech ran out of Tonegen-made replacements, and in my opinion, it is worthy of experimentation in many models. Between the HiVi Q1R, Chris' (chris1this1) early tweeter restorations, and the Midwest tweeters, we have never had better options for as many AR models.

Attached are photos of the new tweeter next to an AR-11 tweeter, as well as one showing its perfect fit in an AR-3 cabinet hole.

Roy

 

 

 

[Aadams]

8 hours ago, RoyC said:

The Midwest tweeter is head and shoulders above any AR 3/4" general replacement tweeter I have seen since the very early 90's when AB Tech ran out of Tonegen-made replacements, and in my opinion, it is worthy of experimentation in many models. Between the HiVi Q1R, Chris' (chris1this1) early tweeter restorations, and the Midwest tweeters, we have never had better options for as many AR models.

Any feel for power response vs the original 3a tweeter?

[ra.ra]

Thanks, Roy, for that fine comparative write-up on the Midwest dome tweeter, and for the excellent pics. Physically, it appears almost identical, and I really like that no delicate tinsel wiring whatsoever is exposed from the front side. My suggestion to anyone using this tweeter would be to not even consider any front-wiring installation, and simply abandon the exposed front terminals and relocate-reconnect the black/yellow crossover wires directly to the rear tweeter terminals.

Taking Chris' excellent restorations out of the equation, the viable 'new' tweeter options are the 3/4" Midwest tweeter at $70 (sans cost of added coil) versus the 1-1/8" Hi-Vi tweeter at less than $20 (sans cost of coil). While the new Midwest tweeter is a virtual doppelgänger of the original driver, a $100 cost difference right off the bat for tweeter replacements will become a consideration for many restorers. Nonetheless, it is very good to know that there is another recommended option available. 

And in that last pic, do those 3's have oak cabinets?    

[ar_pro]

Yes, thanks for the detailed description, Roy. This looks like a viable option for updated restorations.

I also agree with ra.ra about abandoning the front-wired connections; this is just a better idea.

[RoyC]

ra.ra and ar_pro, I completely agree with your comments, guys...though I'm personally curious as to what the leads look like under the covering. My motto seems to have evolved into "if it ain't broke, break it".

Aadams,  As mentioned above, I have no measurements. It is best to think of it as an AR-11 tweeter, which is more than adequate for the AR-3a...but like the AR-11, AR-9 series, HiVi, and any other tweeter of modern construction, the MW tweeter's response will require a crossover modification to properly integrate with early models (3, 3a, 5, 2a/2ax, LST, and LST-2). No tweeter of modern construction has the natural roll off characteristics of the early AR dome tweeters.

Compared to the others, the MW tweeter's primary positive attributes are likely to be its appearance, ease of installation, and as a good general replacement for later models.

Roy

 

[RoyC]

1 hour ago, ra.ra said:

 And in that last pic, do those 3's have oak cabinets?    

The photo is of one cabinet (serial number C19973) of a pair of 3's I acquired from an estate. The speakers were in their original AR shipping boxes which are labeled as "teak". The solid wood front trim pieces do look like oak.

Roy

[lakecat]

Roy...as always...thank you for taking the time to test this new tweeter for all AR lovers out there. Having all these options was but a dream until recently. Kudos to Frank for finding this.

[genek]

Roy, are you planning on taking measurements? Would be very interested in seeing what the off-axis numbers look like, and since AR originally measured their drivers individually we should be able to get an apple vs apple comparison.

[RoyC]

7 hours ago, genek said:

Roy, are you planning on taking measurements? Would be very interested in seeing what the off-axis numbers look like, and since AR originally measured their drivers individually we should be able to get an apple vs apple comparison.

No...the tweeter is back in Larry's shop. 

The off-axis numbers are primarily a function of dome construction and position. I'm willing to bet the off-axis response is at least as good as the AR-11 tweeter, as these tweeters are virtually identical. In fact, the AR-9 tweeter dome is identical as well, with the exception of its (deliberately) recessed position to minimize off-axis response. (One reason the HiVi tweeter does fairly well as an early AR tweeter replacement is its semi-exposed dome.) I'm sure there are differences, but of all concerns regarding the integration of the MW tweeter, off-axis response will easily be the least critical.

After discussing the tweeter with Larry today he said he will continue to sell only the HiVi tweeter as a replacement for early AR models, and he seems to have a large inventory of original AR-11 and AR-9 tweeters for later models. We agreed the greatest drawback to the MW tweeter at this point is cost.

Roy

[JKent]

34 minutes ago, RoyC said:

he seems to have a large inventory of original AR-11 and AR-9 tweeters for later models. We agreed the greatest drawback to the MW tweeter at this point is cost.

Well..... not to contradict my friend Roy but IIRC the MW tweets are about $80, as are Chris's rebuilds. Larry's AR-9 tweets are $139. So yes--the MW tweets are too expensive for Larry to buy and re-sell but for any of us needing a tweeter.........

[tysontom]

On 9/30/2017 at 8:47 PM, Phxjohn said:

And to think they're  "Power Rating: 75 Watts / 150 Watts Max"  which is a whole lot more handling ability than those original shitty little AR tweeters were. 

FM

Don't think for a moment that any (decent) high-fidelity tweeter can sustain 75 watts, let alone 150 watts max, for more than a nanosecond.  That is very deceptive.  Even an original AR cloth-dome tweeter with Ferrofluid will only handle perhaps 5-10 watts continuous power.  What their rating implies is that the speaker "system" into which the tweeter is placed will handle 75 watts.  If you find a tweeter itself that will handle 75 watts, you really don't want to use it in a high-fidelity loudspeaker, because the moving system, voice coil, etc. would be far too heavy for normal high-frequency use.  "75 watts" sounds like the rating of a large compression horn driver from Altec or University Sound, not a direct-radiator dome tweeter!   

 

[RoyC]

3 hours ago, JKent said:

Well..... not to contradict my friend Roy but IIRC the MW tweets are about $80, as are Chris's rebuilds. Larry's AR-9 tweets are $139. So yes--the MW tweets are too expensive for Larry to buy and re-sell but for any of us needing a tweeter.........

Agreed, Kent...That was largely Larry's perspective.   My perspective is that it is too expensive to experiment with for use in early speakers when Chris' rebuilds and much less costly HiVi tweeters are available. On the other hand, I'm convinced there has never been a better post-AR general replacement tweeter for models from the AR-11 onward. For these models the MW tweeter may be as close to a "drop-in" replacement as we are ever likely to see.

Roy

[Pete B]

On 11/2/2017 at 12:40 AM, tysontom said:

 

You are of course joking about a nanosecond.

Here is for example the Dynaudio D21AF taking four cycles of a 6KHz tone burst at 1000W,

note also that there is virtually no compression from 1W to 1000W in this test:

I'd like to duplicate this test and try it on some less expensive tweeters:

 

[tysontom]

On 9/30/2017 at 8:47 PM, Phxjohn said:

And to think they're  "Power Rating: 75 Watts / 150 Watts Max"  which is a whole lot more handling ability than those original shitty little AR tweeters were. 

FM

Don't think for a moment that any (decent) high-fidelity tweeter can sustain 75 watts, let alone 150 watts max, for more than a nanosecond.  That is very deceptive.  Even an original AR cloth-dome tweeter with Ferrofluid will only handle perhaps 5-10 watts continuous power.  What their rating implies is that the speaker "system" into which the tweeter is placed will handle 75 watts.  If you find a tweeter itself that will handle 75 watts, you really don't want to use it in a high-fidelity loudspeaker, because the moving system, voice coil, etc. would be far too heavy for normal high-frequency use.  "75 watts" sounds like the rating of a large compression horn driver from Altec or University Sound, not a direct-radiator dome tweeter!   

 

On 11/3/2017 at 6:26 PM, Pete B said:

You are of course joking about a nanosecond.

Here is for example the Dynaudio D21AF taking four cycles of a 6KHz tone burst at 1000W,

note also that there is virtually no compression from 1W to 1000W in this test:

I'd like to duplicate this test and try it on some less expensive tweeters:

 

Right.  It was strictly a figure of speech, not a "literal" interpretation.  I thought that would be self-evident. 

The point was made that no tweeter can possibly be rated (on its own) for 75 watts, and that was the point I was trying to make with reference to the new AR replacement tweeter.  That new one is not likely to have significantly better power rating than any of the older AR 3/4-inch tweeters.  It is simply a matter of mass, dome weight and the voice coil weight.  To significantly increase power-handling capability, the coil must be heavier, and this is unacceptable in a good tweeter.  In terms of instantaneous bursts of energy, I think the AR-LST was originally tested to 5,000+ watt peaks at one point without any ill effects, but this is strictly short-term bursts of energy.  The AR-3a 3/4-inch tweeter can probably sustain a little over 5 watts, long-term steady-state energy, before burning out.  The later Ferrofluid 3/4-inch black-dome tweeter could probably take 8-10 watts long-term energy, but not much more.

--Tom

[ligs]

I don't think the burst power test with a single frequency is realistic. In my simple mind a tweeter simultaneously produces a wide range of frequencies, covering perhaps  thousands of different frequencies. Each frequency contributes a little bit of heat in the voice coil. 

[lakecat]

{It is best to think of it as an AR-11 tweeter, which is more than adequate for the AR-3a...but like the AR-11, AR-9 series, HiVi, and any other tweeter of modern construction, the MW tweeter's response will require a crossover modification to properly integrate with early models (3, 3a, 5, 2a/2ax, LST, and LST-2). No tweeter of modern construction has the natural roll off characteristics of the early AR dome tweeters.}

Roy.....educate me a little on roll-off. I always read it as a short coming on the 3a and other models and why a super tweeter was added to some peoples units. If the new tweeter doesn't have that "roll-off".....isn't that a good thing?

[rl1856]

On 11/2/2017 at 1:24 AM, RoyC said:

Agreed, Kent...That was largely Larry's perspective.   My perspective is that it is too expensive to experiment with for use in early speakers when Chris' rebuilds and much less costly HiVi tweeters are available. On the other hand, I'm convinced there has never been a better post-AR general replacement tweeter for models from the AR-11 onward. For these models the MW tweeter may be as close to a "drop-in" replacement as we are ever likely to see.

Roy

Given the value of vintage AR speakers, one could justify the cost of the MW tweeter.  It appears to be an  aesthetically identical drop in replacement.   Performance characteristics have yet to be fully determined.  It would seem that final judgment should wait until someone can objectively report how the tweeter sounds in circuit.

One issue to consider is this tweeter will be compared to working original drivers.   Working in the sense they pass signal and sound "ok".   But over time drivers can deteriorate, and our hearing will adjust to slowly changing performance characteristics.  How certain are we that a 45-50yr old tweeter still performs to original specifications ?   If sensitivity has decreased, or HF extension is attenuated, then any comparisons may be invalidated.   The new MW tweeter may be more sensitive and have differing HF extension and off axis performance, but it may also be closer to original specifications than currently working drivers.   Just something to consider.

[ligs]

I am sure some of you are well versed at crossover designs or computer modelling. In theory, you can tailor the level, slope and crossover frequency from any drivers if you have measurement capability. 

[Aadams]

I am not a physicist but 75 watts sustained over any time period is equal to the energy of around a constant 10 horsepower in the same period.   A small tweeter voice coil that could handle that much energy would glow like a small electric stove or perhaps a light bulb.  Your speaker could double as a food warmer or space heater.

Adams

[RoyC]

2 hours ago, rl1856 said:

Given the value of vintage AR speakers, one could justify the cost of the MW tweeter.  It appears to be an  aesthetically identical drop in replacement.   Performance characteristics have yet to be fully determined.  It would seem that final judgment should wait until someone can objectively report how the tweeter sounds in circuit.

One issue to consider is this tweeter will be compared to working original drivers.   Working in the sense they pass signal and sound "ok".   But over time drivers can deteriorate, and our hearing will adjust to slowly changing performance characteristics.  How certain are we that a 45-50yr old tweeter still performs to original specifications ?   If sensitivity has decreased, or HF extension is attenuated, then any comparisons may be invalidated.   The new MW tweeter may be more sensitive and have differing HF extension and off axis performance, but it may also be closer to original specifications than currently working drivers.   Just something to consider.

rl1856, This new tweeter is for all practical purposes an AR-11 tweeter, which is not, and never was, an electrical "drop-in" replacement for an AR-3a style tweeter. AR modified the crossover by the addition of a small series capacitor when the AR-11 tweeter was used as a replacement for the earlier tweeter, and changed the crossover when it was used as the AR-3a Limited tweeter. My point above is that I presently find it too expensive to experiment with when there are already satisfactory solutions for the AR-3a type of tweeter. If anyone here has the $150 for a pair to experiment with for this purpose, I'm sure we would all be interested in the results. My educated guess is it will probably need a parallel coil of around .1mh to work in a similar fashion to the earlier tweeters in models like the 3a, etc. On the other hand, I played around with it enough to believe it is an excellent candidate as a drop-in replacement for any model originally equipped with the AR-11 or AR-9 type of tweeter.

Jeff, I meant "roll off" in the other direction, as this tweeter and the AR-11 tweeter have much more midrange response than the 3a type tweeter. The solution for the AR-11 tweeter, as implemented in the AR-11 speaker, is a .1 parallel coil in the crossover. It is also the purpose of the .05 coil for the HiVi tweeter when used in the AR-3a.

Roy

[lakecat]

Thanks for lesson Roy as I didn't realize you meant that way. 

[harry398]

On 11/5/2017 at 11:20 AM, RoyC said:

rl1856, This new tweeter is for all practical purposes an AR-11 tweeter, which is not, and never was, an electrical "drop-in" replacement for an AR-3a style tweeter. AR modified the crossover by the addition of a small series capacitor when the AR-11 tweeter was used as a replacement for the earlier tweeter, and changed the crossover when it was used as the AR-3a Limited tweeter. My point above is that I presently find it too expensive to experiment with when there are already satisfactory solutions for the AR-3a type of tweeter. If anyone here has the $150 for a pair to experiment with for this purpose, I'm sure we would all be interested in the results. My educated guess is it will probably need a parallel coil of around .1mh to work in a similar fashion to the earlier tweeters in models like the 3a, etc. On the other hand, I played around with it enough to believe it is an excellent candidate as a drop-in replacement for any model originally equipped with the AR-11 or AR-9 type of tweeter.

Jeff, I meant "roll off" in the other direction, as this tweeter and the AR-11 tweeter have much more midrange response than the 3a type tweeter. The solution for the AR-11 tweeter, as implemented in the AR-11 speaker, is a .1 parallel coil in the crossover. It is also the purpose of the .05 coil for the HiVi tweeter when used in the AR-3a.

Roy

thanks for sharing your experience with that tweeter.

I have a question........how can someone determine how much coil is needed when swapping in a tweeter.

example....If someone wanted to drop in a AR9 tweeter into a ar3a cabinet.....how much coil is needed?      or is it trial and error with sound.

 

 

[Phxjohn]

How does my 'PhxJohn' get put on some of these posts ? I never use profanity on audio forums.