Aadams
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Posts posted by Aadams
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Not interrogative but rhetorical: What is your backup plan if you damage the voice coil or the phenolic dome? I can't recall reading that either are practically replaceable. Seems like you would want a "training" tweeter.
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15 minutes ago, SUNNBOBB said:
nce that is all installed, I'll be testing the tweeters to determine if they need to be rebuilt.
The betting line on your tweeters performing anywhere close to original spec would be a 1,000,000 to 1 even if they are perfect on a volt/ohm meter. All of us who have had our tweeters rebuilt know this a near universal pragmatic truth.
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56 minutes ago, SUNNBOBB said:
. Aadams, are you recommending to leave the 5000 cap?
I am saying in the absence of any evidence to the contrary, I would assume they are ok for now, and not spend time and money replacing the Spragues. That single 5000mf is also a sign of provenance. It was replaced by a single 2500mf to make the LST friendlier to a wider range of power amps in the 1970s. Not everyone had a DC300 or MC2300.
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Asumming all components are present and correct, the most audible improvements will be to restore the woofer, rebuild the tweeters, install new fuses and replace the wax capacitors. The can caps appear to be spragues which almost never cause problems.
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From Roy Allison
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Have you considered installing new pots? Much simpler than Lpads.
If you type your thread title as a google search you get CSP hits for the information you seek on lpads.
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Assuming all the drivers are present and correct, the combined value of all the electronics in the room is lower than the value of the speakers that are sitting in direct contact with a concrete floor, being used as equipment stands.
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If your KLH5s appear to have always been in a controlled temperate environment and show no evidence of swelling, my opinion is you don't have a problem. Applying the deadening material you mention could deface the unit with no offsetting benefit. AR 12 inch are similar construction and very numerous, for example, and the issue you address has never been a concern that I can recall. Others may a different opinion.
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I like it. They are more visually balanced. Have you tried putting the backs of the speakers against the baseboard? I think they are designed to be within 2 inches of the wall. Do you have an AR90 Manual? Page 8.
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20 hours ago, Sainicrew87 said:
In all my reading related to particle board over time it tends to expand from moisture cycles throughout the years thus making it resonate more.
Can you show images of how the baffle has been expanded from moisture cycles?
Aadams
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I would try to remove and reuse the filter board. Replace the capacitors before reinstalling in the new cabinets. Your own words work better than Google translate.
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4 hours ago, arcss said:
I will start by recreating 1 pair with new tweeters
What do you mean by recreate? Do you mean custom build? Bespoke?
When you say "new" tweeters, do you mean the later version AR tweeter or a never used new non AR tweeter?
You should use either the pink or yellow fiber glass that came in the cabinet.
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11 hours ago, Earthnz said:
Out of curiosity, won't the weight of the cone on the sagging spider cause the surrounds to be under alot more stress than a properly sitting spider and cone??.... And how common is this sagging spider issue with these woofers??
The answer to your question is a definite yes. If you leave the woofer sitting on its back or front for extended periods, it will develop a genuine sag. It should not be stored sitting on the magnet or suspended face down or in the cabinet mounted face up or down. AFAIK any sag that develops while oriented correctly in the baffle is negligible.
The spider in these large acoustic suspension woofers is floppy and barely springy. Most of the spring support comes from the trapped air in a nearly sealed enclosure.
Aadams
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33 minutes ago, rilke1999 said:
Is it some known way how to fix something covering it with a plastic foil? I
My guess is it has already been fixed at least once. The "foil" covers the fragile leads from the voice coil to the terminal posts at the outer edge. I wouldn't tamper with it except to restore the system to original front wired tweeters. Another member may have different advice.
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1 hour ago, rilke1999 said:
What I found strange in addition is the non painted front? And the small trimming?
The cabinets are original Euro Style with removable grills. It appears the circuitry, at minimum, has been mechanically modified to use modern connectors.
The tweeters appear to be from a later ADD series and do not work properly with the AR3a without internal crossover changes. The only way to know if the crossover has been modified is to open them up.
The woofers are ok but at least one of them is probably not original, which is not an important point as long as both are AR from the same era and work correctly.
The mids appear to be original.
You have already purchased them. What advise are you looking for?
Aadams
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From what you show this is normal. Use shims around the voice coil to position the woofer cone. If you have never used shims don't cut the dust cap before you have seen some of the great examples of the process in this forum. Might be some on youtube.
Aadams
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1 hour ago, Mr. Weather said:
Does anyone have any thoughts on the side grills for the AR-90?
I don't think you will solve the problem with thickness. It is more an issue of overall proportion. The AR9 and 90 woofer grills have identical measurements. Aside from the obvious height difference, their cab depth and width vary by around a 1/2 inch in both dimensions, virtually indistinguishable to the eyeball.
This is a good thread if you haven't seen it.
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Have you verified the tweeters and woofers operate? If they are all working, you got a good deal for 55€.
The pair with back wired tweeters are later versions.
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On 1/25/2023 at 3:56 PM, tysontom said:
AR's efforts with these tower speakers, especially the AR9 and AR90, was well spent!
tysontom
Your statement below, buried in another thread, is quite germane to this AR9 thread:
....when I had both LSTs together, I wired them in parallel and used the 2205 for a period of time, but this amp would enter into the "Power Guard" limited output on frequent occasions. With stacked LSTs, the bass response had more impact, of course, due to the additive effect of mutual-radiation impedance with the woofers fairly close together. This is somewhat akin to the "stacked-Advent" effect that was so widely admired years ago, despite the Advent's other shortcomings. Anyway, I subsequently traded the 2205 amp for a new MC-2500, which I kept for several years. It worked perfectly and provided all the power I needed. I never drove the LSTs needlessly hard, but on some music with wide dynamic range, even the 2500 would light-up the Power Guard soft-clipping lights. The sound was about as dynamic as anything I've ever had either before or since! The AR9s had a wider dynamic range with better clarity, but the LSTs had the most spacious, life-like sound on certain music due to the extremely wide dispersion. "
Aadams
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32 minutes ago, Hodge said:
Thoughts?
It might be simpler to connect another pair of speakers and see if the problem is duplicated. Is your amp a vintage unit? Pre 1990s?
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28 minutes ago, AR surround said:
So just to clarify, the 'sound' you are hearing with the volume at 0 is music that is on the CD, not spurious noise. Correct
Good question it sounds like crosstalk in the amp circuits.
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54 minutes ago, Fentonio said:
They need a recone and then id be interested to know whether its worth meddling with the crossovers
Are all the drivers the correct model numbers and do both tweeter/mid units operate? If the answer to all is yes then it is worth the effort. You could defer the crossover mod and use an equalizer.
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Outstanding!! Based on my memory, it seems you have expanded the information content during the final buffing period. Thanks.
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For Classic AR 12 inch speakers the ideal placement is recessed in a bookcase or a wall midway between floor and ceiling. Every other placement is a compromise and depends on your listening position in relation to the speaker placement and the room boundaries.
Roy Allison wrote the document that describes how to optimize the room placement of a 3 way box speaker. Linked below
Vintage AR-91 purchase
in Acoustic Research
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Congratulations! Nice find. They were designed to be on the floor against a rear wall for optimal bass from room gain. They should compete with the LAs in that position. Difference between a 3a and 91 is more emotional than aural.
Regarding the Banana plugs: I and others here have used 14 awg wire, ring connectors and female banana plugs screwed on the original binding posts to avoid altering the original correctly working speaker parts. JIC you had not considered it.