Just some thoughts which come to mind:
-- Have you removed the grill-cloths and examined the woofers (and the other drivers, for that matter) to see if the surrounds are torn or disintegrating? That commonly happens with 20-something year old speakers, and might account for what you are describing. And if that is the problem, it is most likely repairable.
-- My instinct would be that an ADC equalizer is likely to do more sonic harm than good. Have you experimented with speaker placement, listening position, speaker toe-in, having absorptive furniture or other objects near the speakers rather than reflective surfaces, etc.? Those are generally the kinds of things which should be addressed before resorting to an equalizer, especially an inexpensive one.
-- How have you had the equalizer set? If it is set to boost bass frequencies substantially, perhaps that is what the speakers are unhappy with.
One of the great advances of the last 20 years has been the almost complete disappearance of the graphic equalizer. They were a sort of obligatory accessory for one make systems and I have never heard a system that didn't sound better without them. A really effective equalizer is a very costly proposition and the home models fell far short. Some of the 555s were quite good but I believe that they were made in at least 3 different factories so it is hard to tell if you have one of the better ones. Al gives you some very good advice.
ADS L810's are a classic. The soft dome midrange made them popular. I believe Telarc used ADS in their studio before they switched to ATC - although I don't recall the model. An option might be an old pair of JBL 4435's but if you get them for around $1000 you might expect to have to do some work on them (bumoed up and reconing needed). They have mylar caps in the x-over which also need changing to polypropelene or other suitable higher quality cap. They would certainly rock out and could take everything you throw at them. A newer option might be a used pair of ATC SCM 40 - these also play loud despite they are a small speaker.
I have removed the grills and do so periodically to get the dust off. The surrounds are in great shape. But a light tap on a couple woofers produces an obviously bad sound, what research is indicating might be voice coil scrape.
I will take the EQ out of the loop to test but in general, I've been happy with the results over the years.
Placement is limited but I think near ideal - 10' apart, toe in to the couch 12' away, on custom made stands 12" off wooden floor about 8" from the wall. My room doesn't allow much variance.
I have slight curve up in bass at 125hz and again at 2-4Khz. always something like this.
Any thoughts if a subwoofer would help here to offload the biggest strain from the ADSs?
I am going to run against the current here and lend a voice in favor of the EQ. I have several in my system. The key (provided the EQ does not add too much noise or distortion) is to limit your adjustments to very subtle attenuations. FWIW, a very well known speaker designer once remarked to me that he thought nothing was wrong with having and using tone controls. An EQ is little more than a sophisticated set of tone controls (if designed well). I also suggest a configuration that allows the removal of the EQ from the signal chain at the press of a button (e.g., connect it through a tape loop). FWIW, your EQ adjustments do not imply (at least to me) typical room acoustic issues.
That said, I think your most important task is to determine just which part of your rig is now the weak link. Borrow another pair of speakers, an amp, preamp or source component and see what happens.
While a subwoofer (with a hi-pass/lo-pass filter) will relieve the ADSes of the need to reproduce deep bass, a poorly designed crossover might cause more problems than it solves. I use a pair of Vandersteen 2Wq subs. While they require your mains to have useable response down to 40Hz, they use an unusual crossover scheme that promotes a clean, seemless blend with the mains. You can read more at www.vandersteen.com.
I have no personal experience with Adcom power amps, but everything I've read about them over the years suggests to me that they are very powerful, but not the last word in refinement. The Adcom preamps seem to be much better regarded. If you want to stick with solid state amps, consider amps by Arcam, Odyssey Audio, McIntosh, Classe, Monarchy Audio and others.
Based on your requirements, I can't recommend a speaker (I don't think I've ever heard your ADS speakers), but you'll need one that can output high SPLs, which means you should consider horn-loaded designs and probably avoid most ribbon-based and planar designs.
First off - find a shop that can look at your 810's for you . If you have damaged voice coils this is the equivalent to driving a car with a failed suspension - nothings going to work right.I've heard your speakers and liked them then (20+ years ago) -sold and serviced a lot Hafler 500's over the years.Really suspicious of the frequent thermal shut downs. To be blunt about it - do you listen at head banging volume levels -very,very high volume levels while completely ignoring clipping/dynamic compression? The only reason I think you might not is that I would have expected you to have blown up you 810's by now (probably a few times?).
What sources are you using? Much as I love vinyl - you can suck an enormous amount of power out of you amps trying to reproduce subsonic trash from a non-synergistic arm/cartridge/table/suspension(platform) combination.Take the grill covers off you speakers and observe the woofers while playing at a comfortable volume level.You will see some woofer pumping on most analog systems - but if it is very violent - this could explain a number of things. First - high amounts of subsonic trash are tremendously burdening your amplifier - it's the equivalent of driving around with 30 cement blocks in the back seat. Secondly -your woofers are going to be operating outside their "comfort" range mechanically a great deal of the time - this will massively increase distortion which will be very audible in the lower part of the voice range which is being reproduced by the woofers in the 810.
...But a light tap on a couple woofers produces an obviously bad sound, what research is indicating might be voice coil scrape.
If your speakers are damaged, you're wasting time and money monkeying with the other components. A damaged woofer is going to sound nasty no matter what you do.
It also sounds like you frequently listen at high volume. The ADS, even though an efficient speaker, is a 4 ohm unit and this can be difficult for many amps, but that really shouldn't be an issue for your Adcom. That leads back to a suspicion of speaker damage. Get your speakers checked.
Can anyone recommend someone in the Boston area who can look at my ADS 810's? I figure I'm in the best location given where they were built.
Check with Tweeter, etc. They used to be a big ADS dealer. Maybe somebody still has some contacts. About a dozen years ago I blew out a pair of woofers in my 1987-era ADS 1090s (one generation after the 810), and my local repair shop (in Seattle) was able to replace them with OEM woofers. There are probably some companies around that specialize in rebuilding drivers for spares.
I believe Tweeters has gone out of business. I know the one in my town closed down about the same time Circuit City did.
I believe Tweeters has gone out of business. I know the one in my town closed down about the same time Circuit City did.
Oops. Missed out by just a few months
Looks like the former ADS headquarters is occupied by American Florist Supply Inc.
I had a pair of L1090s that I bought new at the end of their run in 1987. Telarc used the flagship from this series, the 1590, as their monitors at the time. The 1090, 1290, and 1590 shared the same soft dome midrange and tweeter and dual woofers in a sealed cabinet. They varied by woofer diameter and cabinet volume. The 1590s had dual 10" woofers and reached pretty deep. The L1x90 series were preceded by the x10 series (e.g., 610, 710, 810) and followed by the M series such as the M10 and M12.
I also picked up a pair of near mint 810s for $100 and made them my rear channel speakers, as they had near identical mids and tweeters as my front L1090s. I experimented a bit with amplifiers and found that to get the most of the 1x90s or 810s, you needed a fairly powerful, fast, wide bandwidth high current amp that is comfortable into a fluctuating impedance. Telarc used Nelson Pass's Threshold Stasis amps at the time. I found nirvana with a used VSP Labs TransMOS SS amp making 200 wpc and lots of current--it weighed about 50 lbs. Today you can get good results with the more recent crop of wide bandwidth high current Mosfet power amps from Adcom such as the GFA-5400 and GFA-5500. These are fast and transparent, and have a nice liquid midrange and treble that mates well with the ADS dome midrange and tweeter.
Of course, it won't fix things if your voice coils are scraping. One thing to keep in mind, though, is that ADS built its drivers with very tight voice coil gap tolerances. They even built the machines to build the voice coils because nothing was available to maintain their tiny gap. My point is, you may hear a clink when tapping on an ADS bass driver even if there's nothing wrong with it. See if you an borrow an amp
like I described and see if it gives you what you're looking for.
Johnny got a good point - your test procedure for woofer failure may not be valid? I'm going to try and describe how to test for a warped woofer voice coil. Let me make one point first : This is something you do to your speakers - YOURS - never ,ever do this to anyone else's . If you do this on someone's sales floor without first asking for permission - anticipate a violent physical assault on your person - which you richly deserve.In my 25 years in the industry I replaced dozens of drivers damaged by f#$%^&g idiots punching in domes or dustcaps on my demo speakers.Industrywide - you will find service people who have a real attitude about this kind of damage.
First off - this test procedure is only useful for woofers and a very few mid-bass/mid-range drivers that have a fair amount of excursion ( front and back motion).Most midranges and all tweeters that I am aware of will not tell you anything about their V/C condition with this test - you will however have a reasonable chance of permanently damaging them by sticking your fingers into them.
All we are trying to do here is feel and listen for a voice coil that is no longer round and/ or no longer intact ( voice coil wires have come loose).Most woofers have a obvious dust cap over the voice coil it's self - this will be at the exact center of the woofer - DO NOT TOUCH THE VOICE COIL CAP-COVER.Use both hands - spread your fingers evenly onto the woofers cone area a 1/2 inch or so outside the dust cap area and GENTLY press down - you want to get the cone to move as much as possible straight back - if you only press on one side of the cone it will probably scape - this doesn't mean anything- then release the pressure and let it spring forward - it should move forward freely and you should hear nothing. You do not need to push the voice coil to the bottom of the V/C cut in the magnet - if you can move it a little bit - you should be able to tell if it's moving freely and if there is no scraping or rubbing sound from the Voice Coil cap area.If it scrapes,catches momentarily or you hear a sorta whispy higher frequency brush sound when you do this - the voice coil is damaged.If it moves freely with no sound - at least the Voice coil is probably not damaged ( this doesn't always hold true - some prosound speakers have really wide gaps and the V/C can burn out and not scrape - not common on consumer stuff).Anyone who services speakers learns how to do this probably within their first week on the job - while not definitive - it does allow you to separate the obviously damaged from the maybe's - always useful in a service job.This will work work for something like 99% of Hi-Fi woofers ( pulp and plastic/poly cones) - a very few designs use Styrofoam like cones materials - very easy to try this and stick your fingers right thru the cone . If you're not sure - don't try this.
Be careful - but this might be of some help in analyzing your problem.
I've performed the above and I clearly have scraping on 3 of the 4 woofers. A slight tap on the 3 scraping woofers clearly creates a bad sound that I hear terribly when these are playing. Looks like I know what needs to be done. Now to find someone. Thanks all for your input.
You might try calling or emailing Bill LeGall of MillerSound, http://www.millersound.net
(note that it is .net, not .com). He may not do that kind of repair (he mainly does reconing and surround repairs, and he is THE BEST in those areas), but he is extremely knowledgeable about speakers and speaker repairs, and he may be able to point you in the right direction. He is also a delight to talk to.
Your advice is right on. The whispy sound is sometimes sounding as if air was leaking out of the speaker. Another trick I use is to touch the woofer rubber surround very lightly while playing music softly - normally the sound does not change - if it does then VC rubbing may be a problem. Another check is to lightly "tap" the edge of the cone (about an inch inside the surround rubber) with a finger and listen to the sound as you go round the cone...if the sound changes at some point around the circumference then it may indicate a rubbing coil.
I would add that DIY re-coning is not hard to do IF you can find the correct replacement parts (this may be a problem for ADS who is now defunct). See this for a discussion on ADS drivers