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Aadams

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  1. Is that a Hivi QR1? It looks like you cut the screens and removed the damping material from the mids. Where are the Lpads and resistors? In another thread you said you would not bypass the pots. Adams
  2. Powerglide Your meticulous restoration has set a new bar for all of us, especially considering the condition of these when you started. One thing you may not know is the performance of your tweeters is likely so severely degraded that a fair comparison with those JBLs is not possible without a tweeter rebuild or installing a modified HI Vi. Adams
  3. This thread tells you how to store old AR woofers for prolonged periods. I think a few weeks would qualify as prolonged.
  4. If your baffles are chipboard you might want to consider tape only. Mortite caulk works well on woofers but it can bond into the porous surface of chipboard and you can pull out significant chunks of mounting surface when trying to remove and replace. Tape will also be easier on flanges of tweeters and mids for future remove and replace. Adams
  5. Der You haven't mentioned what you consider to be upper mid range. The trick that Roy's mod performs is the blending in the crossover area that closely mimics the transition of the original tweeter but the HiVi does not match the dispersion of the original above the crossover point. The rebuilt originals from both Roy and Chris easily match the sonic performance of a correctly adapted HiVi but hearing the difference in the 5k to 8k range without having a reference speaker will be difficult unless your ear is finely tuned. The good news is you can't go wrong either way. Adams
  6. My two cents. You are unlikely to notice the difference unless you listen to recordings that successfully capture the live quality of a large venue performance and you also have another speaker with which to compare. So, I am saying no big payoff but I wouldn't dump those original tweeters. Adams
  7. Reminds me of an lst post a couple of years back, the problem was in the spectral balance control. I think it needed a deoxit hit or maybe a few rotations to work it out.
  8. Caps spawn a range of responses here. Somewhere in these pages Ken Kantor refers to some as "Cap fantasists" and advises the most correct course is to replace like with like, which means for the 2ax use NPE. Dayton NPEs are so inexpensive you could try one with Dayton film and the other with Dayton NPE and see if you hear a difference. If you don't hear a difference then, years from now, when the foam rots on the NPE unit you can also replace the caps. Assuming all of the drivers are correct and operating properly, if you do hear a difference, that can't be trimmed out with LPads, I will be surprised. Be sure to use lpads. Adams
  9. I think you will need a RoyC answer on this one. My impression is, the coil does most of the work in preventing intrusion into the mid range but maybe the added cap tailors the blending at the crossover point. Keep your old tweeters for possible rebuild. Adams
  10. In an earlier post I said the AR9 was better than the AR3a because it could do everything a 3a could do, out of the box, with very little adjustment, given enough space. After more time listening and comparing both systems, I need to qualify my statement because I realize there are capabilities of the 3a (any Classic dome system) that cannot be duplicated by the AR9. I have been listening exclusively to a variety of live performance recordings that do a good job of capturing the space of the venue. Both speaker pairs are sitting side by side with 5 feet between the pairs and 3 to 4 feet away from side walls. The 9s are square against the baseboard. The AR3a can create a very convincing integrated sound field within 5ft of the listening position whereas the AR9 does not achieve the same quality sound field until 10 feet away. Another difference is, the AR3a has greater depth of field, keeping the same sound quality from 5 to 10 feet. The AR9 achieves the 3a sound field quality at the 10ft mark, after which it begins to deteriorate at the set power level. The biggest difference is, because of the phenomenal dispersion, the AR3a allows the listener to choose listening positions within 5 to 10 feet, that vary the mix of direct and reflected sound, which is very helpful with live recordings. Whereas, the AR9 sound is more focused and reflections that add space to the live recording do not develop until further back in the room and it does not develop perceptible progressive changes in the ratio of direct and reflected sound, at least not within my listening space. My listening room is 30ft deep. At 10 feet the AR9 sounds as good as the 3a. Moving further back, the highs can be heard to fade and a “mid- rangy” quality predominates. The way to fix this with a 9 is to turn up the power and the sound field will be deeper. An alternative for the AR9 is to toe in the speakers to get a better image closer in but this does not alter missing reflected sound and can affect bass performance. Finally, this is a mods and tweaks post. The 3as I am using can be positioned without regard to bass performance, the tweeters are rebuilt originals and I have put in extra effort to balance the mid-range drivers. Out of the box, a pair of AR9s is still superior to a casually set up pair of 3as but a standard 3a, mounted in a wall or bookcase per Roy Allison instructions and no bass equalization, could sound as good if everything is working properly and the mid range drivers are balanced for equal sound level. The 9 seems to need larger spaces to sound its best. A dialed in 3a can sound better than a 9 in smaller spaces where a 9 can be difficult. Adams
  11. That thread has several opinions. If these excellent examples ever come up for assessment against a normative 3a , originality will always require the least amount of explanation. To a knowledgeable observer the AR11 tweeter is an immediate sign of a non-standard configuration that should raise skepticism. Keeping the original internal configuration and putting the mod on the tweeter makes this more of an expedient adaptation that is easier to explain. Without this thread as provenance, an objective, knowledgeable buyer of 3as would discount the value based on appearance alone and even more if the crossover is modified, unless, perhaps, the owner could show the page in the restoration guide on how to electronically reconfigure the crossover to take make an AR11 tweeter compatible with an AR3a. From a performance standpoint, the only tweeter that bridges the 4k to 8k octave across the classic mid and tweeter combo while maintaining the power response of the midrange unit, is the original tweeter. All subsequent tweeters are stronger on axis and yield a different sound when the harmonics and overtones are strong in the 4 to 8 range but the superiority of the 3a tweeter power response can only be heard by using a rebuilt unit that has been tailored to crossover correctly at the 5k point AND if you are listening to source material that contains the information. Adams
  12. One reason would be it is the most flexible approach. In the event one of the old Ar11 tweeters fails the easiest, least expensive and most expedient path to a matched pair would be a Hivi QR1 mod which is based on having a 6mf cap in place. Adams
  13. Lpads, properly setup, are a well accepted tweak and way better than the best used 40 year old pots. The tweeter is not a problem either, cap or no cap, as long as you don't mod the internals to compensate. The new 6 mf cap gets placed on the board but the additional 3.3 is placed in line with the negative terminal wire and connected to the the tweeter so the mod comes out easily if you ever install rebuilt original tweeters. You would have to know what to listen for to ever the difference. PS Don't forget to ask about that lpad resistor. Aadams
  14. Edward Does the black wire running from your tweeter pot have a 3.3 cap spliced near the end? if not remove a tweeter and look on the backside negative terminal or the connecting wire. If no cap found it probably wasn’t installed.
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