A Palfreyman Posted August 15, 2016 Report Share Posted August 15, 2016 Guys, New member from UK and have found this site very useful and have a question for you. I have recently refoamed a pair of 2ax woofers using a test signal to centre the cone and all was well until used at moderate volumes when one of the bass units was making a slight rubbing sound. I partially removed the new surround using isopropyl alcohol and repositioned it slightly which cured this problem. However, if driven quite hard with strongly recorded kick-drum I have found that the other bass driver can make a sort of "farting" noise. Had this driver out and if you push the cone in and out, it is free over the first +/- 1/4 inch of travel but then becomes tight as though being pinched in the gap. Is this likely to be a damaged coil and can anything be done? The speakers were my Father's and hadn't been used for a long time. Thanks, AP Link to comment Share on other sites More sharing options...
djcheung Posted August 15, 2016 Report Share Posted August 15, 2016 Hi AP, Can you check the gaskets on all the drivers ? They need to be air tight. If not, then you will need to install new gaskets. David. Link to comment Share on other sites More sharing options...
A Palfreyman Posted August 15, 2016 Author Report Share Posted August 15, 2016 Gaskets all seem OK. They are all foam about 1/8 inch thick and in good condition. The other woofer can be pushed in / out without feeling "tight" so there is definitely something strange with this woofer. AP Link to comment Share on other sites More sharing options...
djcheung Posted August 15, 2016 Report Share Posted August 15, 2016 Some pics would help . Have you checked the joints between the cone and the spiders ? Cone refoamed at Incorrect height ? What do you mean by 'driven quite hard' ? These are old speakers and I think not designed for rock music ! David. Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 15, 2016 Report Share Posted August 15, 2016 For my money, I would probably want to take a look under that dust-cap....... Link to comment Share on other sites More sharing options...
newandold Posted August 15, 2016 Report Share Posted August 15, 2016 12 hours ago, A Palfreyman said: Guys, New member from UK and have found this site very useful and have a question for you. I have recently refoamed a pair of 2ax woofers using a test signal to centre the cone and all was well until used at moderate volumes when one of the bass units was making a slight rubbing sound. I partially removed the new surround using isopropyl alcohol and repositioned it slightly which cured this problem. However, if driven quite hard with strongly recorded kick-drum I have found that the other bass driver can make a sort of "farting" noise. Had this driver out and if you push the cone in and out, it is free over the first +/- 1/4 inch of travel but then becomes tight as though being pinched in the gap. Is this likely to be a damaged coil and can anything be done? The speakers were my Father's and hadn't been used for a long time. Thanks, AP Hello AP If you like the sound of the 2ax in my opinion it's worth it to have the woofers rebuilt professionally as a matched pair. Is there a reputable shop in your area UK? When I have a woofer that's over 25 years old I never replace only the surround. The spiders get weak after that long and can allow a woofer to bottom out due to excursion beyond its original spec. That being said those who play their music on the quiet side can live with a weaker spider perhaps forever, so to speak. Bill Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 16, 2016 Report Share Posted August 16, 2016 I'm not aware of a speaker shop like that in the entire UK. It's DIY or bust over here. Link to comment Share on other sites More sharing options...
newandold Posted August 16, 2016 Report Share Posted August 16, 2016 5 hours ago, TimmyTonga said: I'm not aware of a speaker shop like that in the entire UK. It's DIY or bust over here. There are many outfits in the UK that completely rebuild woofers. Bill Link to comment Share on other sites More sharing options...
djcheung Posted August 16, 2016 Report Share Posted August 16, 2016 Example like Wembley Loudspeaker http://www.wembleyloudspeaker.com/ Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 16, 2016 Report Share Posted August 16, 2016 10 minutes ago, newandold said: There are many outfits in the UK that completely rebuild woofers. Bill Of course, but I've not found one that will restore them, for which I would consider preserving the cone a minimum requirement. 3 minutes ago, djcheung said: Example like Wembley Loudspeaker http://www.wembleyloudspeaker.com/ Wembley Loudspeakers would laugh at such a notion* regards/Tim *and have done, actually .... Link to comment Share on other sites More sharing options...
A Palfreyman Posted August 16, 2016 Author Report Share Posted August 16, 2016 Guys, Thanks for the replies. TBH I'm not prepared to spend silly money on these especially as both tweeters are open circuit / foam suspension crumbled anyway, just wanted to see if I could get them working reasonably well. I'll have a look at removing the dust cap on the "tight" voice-coil tonight. Just can't understand why this one is free over the first +/-1/4inch and then becomes tight. I refoamed both woofers together using 10" Boston ff foams from Springfield Speakers with a test tone on low volume and of course problems like this don't show up until you work them harder. It is definitely within the bass driver because switching channels over on the amp, the fault stays with the speaker and other speakers on the same amp are all OK. Link to comment Share on other sites More sharing options...
TimmyTonga Posted August 16, 2016 Report Share Posted August 16, 2016 Just in case you haven't removed a dustcap before AP, I would check out this post before you knife it. Assuming it is original, you should ideally cut it in such a way as it can be replaced in its original position. Which is easier than replacing it with a new one anyway, but needs the right tool (X-Acto knife with a #11 blade is a board favourite). tim Link to comment Share on other sites More sharing options...
owlsplace Posted August 16, 2016 Report Share Posted August 16, 2016 Is this an alnico woofer? If so, you should be able to get a look at the base of the voice coil former through the side of the yoke by removing the masking tape cover. The former may be damaged from physical impact or melted by a defective amplifier or the wire may have separated due to failing cement. These drivers are easily acquired on the used market for reasonable prices. Roger Link to comment Share on other sites More sharing options...
newandold Posted August 16, 2016 Report Share Posted August 16, 2016 2 hours ago, A Palfreyman said: Guys, Thanks for the replies. TBH I'm not prepared to spend silly money on these especially as both tweeters are open circuit / foam suspension crumbled anyway, just wanted to see if I could get them working reasonably well. I'll have a look at removing the dust cap on the "tight" voice-coil tonight. Just can't understand why this one is free over the first +/-1/4inch and then becomes tight. I refoamed both woofers together using 10" Boston ff foams from Springfield Speakers with a test tone on low volume and of course problems like this don't show up until you work them harder. It is definitely within the bass driver because switching channels over on the amp, the fault stays with the speaker and other speakers on the same amp are all OK. Hello AP Your last post is very telling indeed. I would respectfully suggest that you put the exacto knife back on the shelf and hold everything for just a moment. The first thing are the tweeters which you described as open circuit (dead at the moment) secondly, you said silly money (I like that...have not heard that one in this part of the world). The first thing you may want to decide is what constitutes "silly money" and proceed from there. I had the 2ax for around 5 years and those pots on the back were notorious for sound dropping out from oxidation. That said, there is a good chance the tweets are ok after cleaning the pots but if not well silly money? So if the tweeters ARE dead that will be much more serious than the woofer issue with the tweeters being much harder to obtain. One way or another, that woofer can be restored. Anyway my advise is to turn the project around and be sure the tweeter/mid section is viable before going further Bill Link to comment Share on other sites More sharing options...
dxho Posted August 16, 2016 Report Share Posted August 16, 2016 On 8/15/2016 at 3:36 AM, A Palfreyman said: Guys, New member from UK and have found this site very useful and have a question for you. I have recently refoamed a pair of 2ax woofers using a test signal to centre the cone and all was well until used at moderate volumes when one of the bass units was making a slight rubbing sound. I partially removed the new surround using isopropyl alcohol and repositioned it slightly which cured this problem. However, if driven quite hard with strongly recorded kick-drum I have found that the other bass driver can make a sort of "farting" noise. Had this driver out and if you push the cone in and out, it is free over the first +/- 1/4 inch of travel but then becomes tight as though being pinched in the gap. Is this likely to be a damaged coil and can anything be done? The speakers were my Father's and hadn't been used for a long time. Thanks, AP It is possible that the woofers could be corrected by removing the surrounds from the frames or the cones, using shims to center the voice coil, and then repositioning the surrounds. The one that is tight through part of its travel could be caused by the surround holding the cone/voice coil at a slight angle. Link to comment Share on other sites More sharing options...
A Palfreyman Posted August 17, 2016 Author Report Share Posted August 17, 2016 Thanks again for the pointers. I have read the 3a restoration guide a couple of times and I have already had the "stuffing" out of these and removed and cleaned the pots which weren't in fantastic condition (crusty / corroded) but have been cleaned sufficiently to be usable with only occasional drop-outs. Whilst the pots were out I measured the tweeters and they were definitely open circuit (I checked them several times to be certain) and the 3 small bits of foam around the outside were degrading so they are shot. Thanks for the suggestion about examining open-frame alnico woofers - I will remove some of the tape and see which type they are first before going any further. Depending on what I find I may then also remove the outer periphery of the newly fitted foam and see if this relieves the tightness: isopropyl alcohol worked well on the other one which was slightly mis-aligned and allowed it to be reglued successfully afterwards. If it does relieve the tightness, I will shim the v/c and re-glue. I have successfully re-foamed several other drivers recently using a test tone (up to 8" in some Heybrook HB1s) but these 10" woofers seem more sensitive to alignment so it looks like it is best policy to shim these. AP Link to comment Share on other sites More sharing options...
djcheung Posted August 17, 2016 Report Share Posted August 17, 2016 Do your tweeters look like this? The problem I had with one of the tweeters was the connection of the thin wires to the post. They are so thin and brittle. It snapped but not obvious. The fun starts when you try to solder them. I used a bit of conductive paint to joint the 2 ends and so far it is holding up ok. Link to comment Share on other sites More sharing options...
djcheung Posted August 17, 2016 Report Share Posted August 17, 2016 This is the pair I refurbished a couple of years ago. Link to comment Share on other sites More sharing options...
newandold Posted August 17, 2016 Report Share Posted August 17, 2016 45 minutes ago, djcheung said: This is the pair I refurbished a couple of years ago. Beautifully done! In the five years or so that I had my pair I never had the grilles off. (Sold them before it became necessary.) Bill Link to comment Share on other sites More sharing options...
lARrybody Posted August 17, 2016 Report Share Posted August 17, 2016 Your speaker look wonderful. Looking at those tweeters they appear to be from a earlier set which had the cloth surround woofers. The current woofers are from a later model with the four screws. You can still see the six screw holes from the original woofers. Did you have to fabricate some kind of adapter ring to fit those woofers? Looks to be a excellent adaptation. Link to comment Share on other sites More sharing options...
djcheung Posted August 17, 2016 Report Share Posted August 17, 2016 Thanks Larrybody, I got them like that. I read somewhere that they may have changed the woofer design with a smaller basket but a lot of leftover cabinets with the larger hole so they created an adapter ring for them.Not too sure that was AR or previous owners. Link to comment Share on other sites More sharing options...
owlsplace Posted August 17, 2016 Report Share Posted August 17, 2016 1 hour ago, djcheung said: Thanks Larrybody, I got them like that. I read somewhere that they may have changed the woofer design with a smaller basket but a lot of leftover cabinets with the larger hole so they created an adapter ring for them.Not too sure that was AR or previous owners. Looks like a replacement woofer from 1975 ... I would consider restoring a set of early 2ax's even though I never heard a pair. These look nice. Link to comment Share on other sites More sharing options...
lARrybody Posted August 17, 2016 Report Share Posted August 17, 2016 Thanks djcheung for the pictures and explanation. I know AR did do some retrofitting of speakers when changes were made. I have a pair of 2a's that were factory retrofitted with a 31/2 in tweeter and baffle board to become 2ax's. Don't know if AR or a owner made the adapter ring, it is a ingenious solution. A Palfreyman let us know if a realignment of the woofer surround takes care of your problem. I had a similar situation and it turned out to be separated spider from the cone. I did get it reattached with some epoxy, but it was a real tedious pain. Owlsplace, when I mentioned a earlier version of the 2ax I was referring to the pre 1969 version with the orange dome tweeter and cloth surround Alnico round canister magnet. The speaker on the left has the 6 screw ceramic woofer, center the 6 screw alnico woofer and orange dome tweeter, and the right is the four screw ceramic with the smaller frame. All have been rebuilt on the inside, just not the exterior. The dust caps were added when I shimmed the voice coil and installed the filled fillet type surrounds. Link to comment Share on other sites More sharing options...
ra.ra Posted August 17, 2016 Report Share Posted August 17, 2016 Interesting thread, and terrific pics from djcheung and larrybody - - great looking speakers! Another discussion of some minor differences is presented in the following thread. On the woofers with the adapter ring, one detail stands out. It appears that the ring is attached to the metal basket with rivets, and I'm wondering if the "rough" end of those rivets posed any problems when applying new foams. Link to comment Share on other sites More sharing options...
owlsplace Posted August 18, 2016 Report Share Posted August 18, 2016 4 hours ago, larrybody said: Owlsplace, when I mentioned a earlier version of the 2ax I was referring to the pre 1969 version with the orange dome tweeter and cloth surround Alnico round canister magnet. The cloth surround woofer with the phenolic dome tweeter would be my preference. I have asked before but never received an answer how the "red-domed" tweeters have held up in terms of output especially in terms of differences in sound with the later 3/4 inch paper domes. Link to comment Share on other sites More sharing options...
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