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genek

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Posts posted by genek

  1. If you consider the amount of hand work that went into AR speakers even during the Teledyne era, a "new" version of the ar9 in the very limited numbers of both drivers that would have to be made and assembled units that would likely to be sold would most likely be solidly in the "high end" world. Figure on somewhere between $10k-$15k.

  2. Ken Kantor designed this. He didn't come right out and say it, but my impression talking to him about it was that TPTB at AR decided that a 12" woofer would have given the MGC-1 TOTL status instead of the company's then current flagship model (which, I think, would have been the AR9LS).

    The MGC-2 was allowed the 12" woofer, but whether it was a last ditch effort to make an MGC they could sell or there was some other reason, Ken didn't seem to have any thoughts.

    I think that today multi-channel amps and surround speaker arrays have taken ownership of what the MGCs were originally intended to do, but if I could get my hands on a pair, I'd be talking to Ken for advice on how to retrofit them with 12" woofers and bypass the original delayed-signal circuits for the side-firing drivers.

  3. Those were all pretty short, and intended to raise the bigger bookshelf speakers off the floor just enough to avoid undesired bass reinforcement if the user couldn't position them optimally. It wouldn't be until the Holographic series in the 90s when AR produced stands intended to raise speakers all the way up to ear level as a design feature.

  4. The AR-5 failed in the market because instead of seeing it as a sort of lesser AR-3a as AR tried to pitch it, potential buyers just saw it as a more expensive AR-2ax, with the only difference between it and the 2ax being a different mid driver. So in all likelihood, in order to succeed an 8" 3-way would probably have had to be priced at or near the price of the AR-6 (which, btw, didn't really sell all that well either compared to the AR-4 series, as we can see from the much smaller number of them that show up used compared to 4s).

    However, my guess is that the biggest reason there was not an 8" classic AR 3-way is that the response of the 8" driver went high enough that a mid driver just wouldn't have added anything in the way of performance. We didn't see any 8" AR 3-ways until well after the Teledyne acquisition and the departure of Roy Allison, at which point AR's original primary focus on audio performance had given way to designing speakers based on mass market preferences, especially at the low end of the market where there were consumers who would pick a 3-way solely because it had more drivers.

    BTW, if you browse the library section for Allisons, he only seems to have designed one 3-way with an 8" woofer, the CD8, which does use the same high and mid drivers as its 10" sibling, so that's probably the closest thing you're going to find to an 8" 3-way based on the same design priorities as a classic AR.

  5. Boiled linseed oil (which today is not really boiled, but is catalyzed using a petroleum distillate additive), combined with oxidation over many years, is what turns the original reddish tone of the walnut dark brown. How dark will depend on how many repeated applications of oil and how many years since. If you go to a museum and look at walnut furniture made in the 1800s or earlier, much of it will be almost black in color after 100 years of aging.

    If you're working wood items that are potentially valuable antiques, you never want to refinish. I've seen family heirlooms reduced from $25,000 antiques to $500 used furniture because someone didn't like the dark wood and gave it the Formbys refinisher treatment. Though I doubt that AR speakers are likely to reach those lofty heights of desirability.

  6. Very interesting. I didn't know AR made a passive subwoofer. I see their cheaper powered subs on the used but never something like this. What is the model of it called?

    Heck, perhaps this is "sacralige" however, I'd probably visit the Parts Express website, order the subwoofer plate amplifer, matching cross over and port tubing...

    That's must me thinking out loud... ;-)

    Adding a port to an acoustic suspension cabinet would require a huge amount of measuring and tuning. Otherwise, you'd just destroy your bass response.

  7. Thanks to all who are reporting spam messages. Please keep it up!

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  8. Perhaps I'm missing something here. I thought the ONLY mods he's making are to the crossover network. Is something else being changed? Not the drivers, not the enclosure, not the stuffing? What else is there?

    Nothing, that was my whole point. If there's no change in the drivers, stuffing, cabinets, etc., and the original and modded-crossover speakers are both placed identically and used to play the same recordings, it should be possible to assess what changes the crossover mods have made in the way the speakers sound, and for a listener to make a subjective decision as to whether one sounds "better" than the other. It should even be possible for a listener like me to do it, as long as the modded speaker has its HF control tuned as close as possible to the original so that the only measurable change is the leveling of the response curve. All the other items you cite as affecting sound should not factor into a comparison if they are the same for both speakers.

  9. Genek you ask a frustrating question. Better playing which recording and better in who's opinion?

    In this case, I would say the answer is in Dave's opinion.

    I would be a terrible person to use as an evaluator, because my listening preferences are decidedly bent toward the classic AR sound; I don't even care much for most of AR's own products after the ADD series. I might perceive an improvement from flattening out dips and bumps, but if the resulting speaker has a modern "flat and accurate" sound, I either won't like it or will be reaching for the HF control to dial that classic AR rolloff back in.

    Will it sound more accurate or less accurate to an original acoustic musical instrument? That again depends on the other variables of the recording, the room placement, and the room acoustics.

    If the original and modded speakers both have the same drivers and cabinet and are both being used to play the same recording from the same location in the same room, it seems to me that variables other than the crossover mods should have a minimal effect on the question. What would cause this not to be the case?

  10. I think that will depend almost entirely on what is played through them. As properly functioning amplifiers and CD players sound pretty much alike, the variable is the program material. My experience is that the variations in the way recordings are made is equal in variety and degree to the variations in speaker performance. Room acoustics and speaker placement are also a major variable factor.

    Yes, but all of these things are outside of the changes Dave is making in his speaker. The question is. when the modded speaker is A/B'd next to the original under the same conditions and with the same program material, will it sound better than the original?

  11. It would be interesting to see how the best version of Audio Note's expression of this idea which I think costs over $15,000 stacks up against AR4x whether in its original form, as tweaked here, or as tweaked using other means such as a graphic equalizer. There might not be much difference.

    I don't know about you, but being able to take a 40-year-old speaker that sold for $59 each and make it sound not much difference from a modern pair of $15,000 speakers just by updating its crossover doesn't sound like a particularly absurd limit to me. Although it probably will end up moving this thread to mods and tweaks.

  12. It seems like an awful lot of trouble to go to to improve what was Acoustic Research's least expensive loudspeaker of the time, clearly their maximum compromise of performance for the sake of economy. When AR set about building a better model, they took an entirely different route, they built three way systems recognizing the inherent difficulties of matching only two drivers to cover ten octaves.

    40 years after the fact, there's not much else to do with them, is there? It's not as if you can just run out and buy AR's latest version at Best Buy.

  13. There was a time when High Fidelity was using the CBS test chamber and running axial, hemispherical and spherical curves. Those were pretty revealing and would at least tell how the tweeter performed in terms of better dispersion. They would also show whether the bump above 10k was improved, although I would consider that a minor fault (especially with 54 year old ears!) Do you have a way of scanning and attaching?

    Here are the curves. From the description in the text, they appear to have been made with the tweeter control set at the Normal position. The full article is a big scan, but if you want it I'll see what I can do to reduce the file size.

    post-102742-1266536997.jpg

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