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I'll certainly give the drivers a push and see /hear if there is any leakage . I only had the 8 inch drivers, no tweeters at this time.Dr Bunsen Honeydew wrote:Push the bass driver in and see if you hear a hiss from anywhere around the cabinets. I forget did you get Doc Mod tweeters or others. How long did you run them for, they need a couple of weeks of continuous use to run in. Un run in sounds like you heard, also a slight muddyness that disappears when they run in.
It was about 10-11 weeks between finishing the Doc Mods and finding the first pair of vintage speakers so they should have been well run in.
The sound of the speakers did seem to become more relaxed with time as I remember, but as it has been a few months since I last used them I don't have a direct memory of what they sounded like exactly. As always it will be interesting to listen to them again. I might put them on the end of the AP20 for the time being but positioning is going to be less than ideal as they will need to be about 2 inches out from a stud wall.
you have probably forgotten the story about me buying Allison One speakers quite a few years ago, but the upshot of the story was that the crossovers were smashed to buggery. Anyhow it occurred to me today, can these be doc modded or are they not suitable?
When I first tried them, they needed huge amounts of power to get any volume from them, and at the same time most of what I could hear was the tweeter distortion. I heard much the same when I took them to Colins place. Putting them against a wall helped by bringing the bass up, but I could still hear the tweeter having a hard life.
So DrB suggested I tweak the resistor in series with the tweeter. Took them apart, and it had a 12R and 3u3 cap in series. Having a quick measure with some pink noise and a phone app like Steve uses showed a interesting peak at 4k. I would guess about where I heard the nastiness. But the HF and LF were about the same level, so I didn't want to alter the resistor as the overall levels seemed about right. The 4k peak made me wonder if the tweeter and woofer were overlapping more than they should, so I tried a 2u3 cap in place of the 3u3 cap (well actually two 4u7 in series as that's what I had on hand), the measurement now showed the peak at 4k had gone away, and listening to them it was much better. TBH, very much better, I have had a couple of evening listening to them now, and they do do a lot of things right, lowest bass is missing, but given the size of the box its rather impressive. The tweeters are held in with bluetac at the moment, and keep falling out.
I have some caps on order, and will try 2u2 and 2u to see what's better, and then glue the tweeter back and take them to Owston.
Still needs shedloads of power to get any volume, and I don't think they can do the loudness I would need for a 100% of the time speaker, they wont replace the OB's as they stand, but its rather annoying that they have made me aware of some things that fostek could be doing better.
I have to now believe there is merit to treating the cone. I will have to get those Graham 5/9's and try them just to make sure I am not being impressed by the difference instead of some absolute value in them.
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Glad the cap tweak has sorted it. Whether I'll get the chance to try them again I don't know, but I confirm that the heavy totally sealed box and tautly damped main driver, coupled with an excellent and basically 'sweet' tweeter does work incredibly well, even as they were and used with NVA amps, which have no hardness or grain to them.
P.S. One of them had a tiny air leak and believe me, in THIS speaker, it was clearly audible on powerful bass notes. The bass cone really does need to be almost impossible to push in and it should spring straight back out with no gentle motion.
I've been looking in the archive to try and find faceplate size info for the tweeters but without success, can you let me know what the measurement is? It seems that the cut out required is either 70mm or 72mm from what I've been able to find.
Does anyone who has fitted the tweeters have pictures of them that they can post or link to?