Aadams

Don't think anyone has reported doing this. The HiVi is not a mod that would be popular for post AR3a now that Midwest Speaker sells a reportedly excellent replacement unit for all ADD and 9 series that works well when installed in pairs.

When making minimum power recommendations, I think AR assumed that the serious listener would be in a quiet room, with the speakers and that equalizer controls would be used judiciously. In fact, all decent full- range speakers for the home, sound the same when you listen from abnormal distances or from the next room, or listen through walls. Nuance is gone. The only difference left is loudness per watt. Abnormal listening requires more watts. Another significant variable is the difference in our hearing acuity and musical taste which could lead to overemphasis of certain frequency bands using an equalizer; for example, bass boost that enhances percussive effects can seriously increase wattage peaks but does not increase the actual dynamic range of the recording. I agree more watts are better, but the actual amount needed is not nearly what we frequently imagine. AR LST Power handling - at 4 ohms with FNM 2 fuse- Long term average 23 watts; 30 seconds- 64 Watts AR3a - Power handling - Less than LST AR LST and 3a Electrical efficiency – Identical @ .8% AR LST and 3a Sensitivity – Identical @ 89.5 db AR LST and 3a Recommended minimum amplifier 25 Watts AR LST and 3a Listening distance vs SPL with 1 Watt input 1 meter @ 89.5db (Lawnmower) 2 meters @ 84.0db (Borderline hearing damage) 4 meters @ 78.0db ( Long term safe SPL) 8 meters @ 72.0db (very loud conversation) Dynamic range of 32 watt @ 4ohms amplifier driven at continuous average .5 watt = 18db or 107.5 db @ 1 meter 1 watt = 15 db or 104.5 db @ 1 meter 2 watt = 12 db or 101.5 db @ 1 meter Dynamic headroom of a 32 watt @ 4ohms amplifier driving AR LST or 3a at continuous average output of .5 watt = 18db headroom or 107.5 db peak @ 1 meter for 89.5db sensitivity 1 watt = 15db headroom or 104.5 db peak @ 1 meter 2 watt = 12db headroom or 101.5 db peak @ 1 meter Dynamic headroom of a 32 Watt @ 4ohms amplifier with 3db to 6db of room gain 21 db to 24db Other reference points - - Max peak above reference level of recorded music 15db. - - Maximum continuous average SPL without damage to hearing - 80db - - Minimum average SPL at which hearing protection is required in the workplace -85db - - Average SPL of a 5 hp push mower @ 1 meter – 90db - - Average SPL of normal conversation- 68db

Wide dynamic range music recordings seem to always involve percussion instruments at the highest peaks of loudness. These are some examples of accessible, non-esoteric works recorded with sufficient fidelity to span 12 to 15 decibels between the softest to loudest moments.

If the problem remains in the same cabinet after the swap it could be the crossover or perhaps even something loose inside. The chances are low that two out of three drivers would have the same buzzing sound at 800hz.

To be bullet proof, all you need is enough 4 ohm rated watts to achieve 15db of headroom. Keep in mind that most recordings don't need more than 9db of headroom. Recordings of solo concert grand piano and some orchestral recordings or any recording that relies on a low noise floor to hear all of the music, can hit 12db to 15db. Unless you listen to Hirez movie soundtracks you will never need 20db of headroom. The chart below is from AR and applies to all of their speakers. 106db in watts is 100 times the power required at 86db, which is the average continuous safe listening level for your ears. "Mac watts" refers to the tendency of McIntosh to publish power ratings for products that can be as much as 30% below actual performance capability.

All of your mid drivers appear to be 3a style mids. Swap the 3a mid in question with the 3 mid. The crossover in the 3 is 1000hz. You should have a working 3a pair and the mid in the 3 that buzzes at 800hz may no longer have an audible buzz.

What price purity? Performance vs Appearance. Consensus is: 1. The Midwest .75 tweeter is a good replacement, no mods required, for all 12 inch 3 and 4 way from 10pi through AR58s when used in pairs. The only purist replacement for the AR3a or AR5 is a rebuilt original. 2. No one yet rebuilds the dome midranges, but Midwest has introduced an AR9 series compatible mid-range that will work in a 58s in pairs. 3. New replacement woofers and reconed woofers are to be avoided unless there is no other option. If cost is not a barrier contact @Chris1this1about rebuilding your broken AR91 tweeters. Adams

They were billed as a rock n roll speaker and had a very short life. The real value is in the drivers. Adams

Thanks for this. From the time I joined CSP, his presence on the forum was ubiquitous it seemed, posting as late as March 2020, then he vanished. There are a few recent threads still awaiting his reply. His last visit to CSP was April 2020, the month he died. RIP RA RA Adams

Hello Charles You've been away for a while. Which habit are you asking about? Frequency of application or material applied? I prefer Howard's Feed and Wax over linseed oil or Watco for maintenance. As for frequency, I dust weekly but can't remember the last time I re-oiled or waxed a cabinet.

Is the 200028 or the similar 200044 an ideal substitute in a 525hz crossover? NO. Is it an adequate substitute? Depends on the listener's tolerance.

Finally saw the translation.

Giovanni I am not referring to use of the 200028 mid in the AR9 but as a substitute mid in an AR 3 way with a 525hz crossover, for example AR3a,11,...................

The AR9 mid has a resonance of 800hz. The region from 525hz to 800hz is over a half octave. Whether or not you would hear the difference would depend on how attentively you listen and to what you listen. It is easily in the female voice range.

Start a new thread and supply good quality photos of both front and back with grills removed.

I have seen the pressurized box topic mentioned somewhere in a general discussion about packing and shipping speakers but I don't think it was here. Something I have seen but cannot find here and you may know: Did Roy Allison upgrade E. Villchur's personal AR3a pair with his Allison tweeter? Thanks Aadams

Legopart Are you in the US? If so, there are two small, reputable service locations that can repair these tweeters. If this were a simple mechanical repair more of us would be doing it. The tweeters are restored in matched pairs. This forum is dedicated to the restoration and maintenance of AR speakers with emphasis on originality. If your intent is to rebuild yours with modified crossovers and drivers then this discussion more properly belongs in the mods forum. Aadams

Wild guess. Aside from the obvious extra driver protection from box punctures it might also be a baffle to check sudden changes in air pressure caused by rough handling.

I am putting this here because it is not speaker specific. https://www.linkwitzlab.com/AES-NY'09/The Challenge.pdf Above is a link to an interesting AES paper from 2009 entitled "The Challenge to Find the Optimum Radiation Pattern and Placement of Stereo Loudspeakers in a Room for the Creation of Phantom Sources and Simultaneous Masking of Real Sources." According to the author, one of the big impediments to finding the optimum setup for listening in the home is lack of quality live recordings. For example.." Far fewer recordings capture a realistic sense of space. They are mostly found amongst classical music and jazz, which are frequently recorded in their normal venues. The use of spot microphones often introduces artificial sounding spatial effects in these recordings. For example, the solo piano or violin becomes too large and close. Instrument groups slide to the center when it is their turn. Such distortions and temporal changes in spatial presentation are readily heard." and later ............"This reference must be the live performance, our perception and memory of it. Thus the listeners in the proposed tests should have familiarity with unamplified sound, with live acoustic music. Also the human voice in different environments, single or in groups, is familiar to everyone and recordings of it should be part of the listening tests. " I prefer recordings of live venue performances and good ones are indeed difficult to find.

This is what AR said about the AR11 with its new tweeter and "improved" woofer but without stating in what ways the AR11 was better than the previous standard of sound. “The AR-11 is the most accurate speaker system ever made by Acoustic Research. Its performance, drivers, and crossover are identical to those of the AR-10π, except that the Ar-11 does not incorporate a Woofer Environmental Control and the associated crossover components.” Meanwhile Allison had created this evolutionary product which looks much like a classic AR dome tweeter Villchur was very pleased with Allison’s new products. In a speech to the Acoustical Society of America in June 1997, he said: “No one has imitated the Allison tweeter, a sort of pulsating version of the dome tweeter…. I consider it a significant improvement over my original dome in addressing the same problems I did.” (from "The Villchur Blog") So I agree, and speculate Mr Allison would have used the orange dot tweeter, given the choice of the two forms of AR tweeter in the original post. The cloth tweeters mark the split between AR and the Allison/Villchur philosophy of sound reproduction.

Assume both of the tweeters pictured below were available in 1970. Question: Which tweeter would Roy Allison choose to best meet the performance goals for his domed mid designs? Specifically LST, 3a, AR5?

Those can be repaired by RoyC. Click on @RoyC to send him a message.

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. 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.

Neither. It is the power delivered to the speaker terminals. There is no analogy that is less lengthy than the direct statements of the first paragraph under the power handling caption on the spec sheet located inside the back cover of the AR9 manual.

if you are in pursuit of free low distortion bass you could use walls and corners but you may not like other changes that can happen. If they are currently toed-in 2ft from any wall and off the floor it will be difficult to improve what you are hearing from 80hz upward. You should try it if it is convenient and low effort.