Author Topic: SWR 3X10 (Read 161 times)

mikedm · « **on:** February 20, 2004, 02:54:21 PM »

Okay it's supposed to be a 4x10 and if you count the one non-thumping speaker, it is. I've taken an exploratory look-see at the cone, magnet and connections. I can't see any damage to the paper or wires. Everything looks to be in place, nothing loose, nothing hanging free inside the cab. Before I look into replacing the speaker, I might be able to borrow a VOM for basic checks, but is there anything else to look for?

The frustrating aspect is that I was going to sell/bargin this piece to help ease the way for a 2x10 with horn/1x15 combo to bi-amp with my F1X. I don't feel right unloading this thing as it is. On the other hand, I don't want to spend too much to repair...

Any ideas?

thanks in advance,
Mike

poor_nigel · « **Reply #1 on:** February 20, 2004, 07:57:05 PM »

Disconnect it from the path of the other speakers. An ohm meter across the leads (off the terminals) will tell you if it needs reconing or not. It is possible a terminal is bad, that is why you do it off the leads. If you don't have a VOM, you can use a 9 volt battery and some wire. It is irritating to the ears, but lets you know if it is good or bad. Some speakers can be gotten cheaper off eBay than the price of reconing them. Generally, speakers are good or bad, as there is little to them except a voice coil, leads, and the suspension that can mess up. Hope this helps.

mikedm · « **Reply #2 on:** February 21, 2004, 09:05:44 AM »

P-N,
Thanks. I tried the battery test this morning, cone moves just fine, accompanied by an un-nerving hiss and thump.

Inside the cab the top pair of speakers are wired in series, the bottom pair likewise. Both pair acting in parallel. The speaker is question is the first in series of the top pair. I would guess that a bad terminal would end the signal chain there and the second speaker (upper right) wouldn't move either (?).

So now the cone moves when tested with a nine volt battery, but not with a signal from an amp...

Cabinet is specifically the Goliath III, has the additional Fostex horn. I don't know how that compares with other SWR 4x10s. It does have a Level Control range adjustment on the back form 0 to infinity (-dB). I turned it down when I added the F1X to the chain. Not sure if this would have any effect.

I've tried to contact SWR Engineering, no response as of today.

poor_nigel · « **Reply #3 on:** February 21, 2004, 10:40:21 AM »

This is not making logical sense. If the second speaker plays, then it would mean you have a short in the first. If you have a short in the first, then touching the battery should not have produced 'sound/movement.' You did isolate the first speaker when you touched it to the battery, so it was not the second making the noise and movement? I am sure you did. Next step is a VOM. Why? Very unlikely, but it is possible that you have a short across a section of the coil so that it is using only a couple of turns. A nine volt battery will make it move, even if only a couple of turns were left. Resistence would be very low and probably less than an ohm. The speaker should still work by itself, but at much greater diminished performance than the others.

If you isolated the speaker and ran an audio signal through it and it would not play, I would toss it or recone it, depending on the expense of reconing. I am hardly an expert in electronics, but this is not rocket science, and the piece seems undependable. Reconing maybe $50 or less, depending on the speakers and kits the shop is using. eBay sells about everything, and you can probably find a suitable replacement for around $25, but time is money, eh? SWR should be your best resource in this case, if it has to do with the attenuater. Without being there to inspect it, this is all I can think of. I wish I could do better here.

mikedm · « **Reply #4 on:** February 21, 2004, 12:17:00 PM »

I appreciate your time anyway.

SWR happened to email a reply and schematics this afternoon. It took a week, but I'm thankful none the less. Their suggestion is to locate an SWR service rep and have them check it out.

thanks again,
Mike

xlrogue6 · « **Reply #5 on:** February 23, 2004, 08:15:00 AM »

Truly mysterious--the only possibility I can think of is that the suspect speaker is out of phase with the other 3--you might try reversing the leads to the offending speaker. You might also try detaching the leads of the suspect driver at the working speaker of the series pair and take an ohm meter reading to make sure that the leads are good.

mikedm · « **Reply #6 on:** February 24, 2004, 04:34:31 PM »

Could a speaker become out of phase over time? I've had the cabinet for a few years and haven't noticed any issue with this particular speaker before...been really busy lately and haven't had chance to borrow a VOM, that's my next step. It's been raining continuously for a few days now, I'm not about to drag my cabinet into a dealer.

nigel, xl, thanks for the tips, I'll keep plugging away

poor_nigel · « **Reply #7 on:** February 24, 2004, 11:40:00 PM »

Don't bother with a dealer. As soon as you walk through the door, you might as well have replaced the speaker, and if the speaker does need replacing, your cost on it just doubled, probably.

Disconnect the wires to the speaker and put the meter on it at its lowest setting. It should read close to the value stated on the back of the speaker. If it reads less than two ohms, and is not rated two ohms on the back, recone it or replace it. It should not read infinity, or it could not let the other speaker play. It should not read more than an ohm or two above its rated ohmage. If the speaker reads in the range of what it is rated at, start isolating the wires and the attenuator and use the meter on those until something does not read what it should. Seems to me that the attenuator should be for a horn and have little to do with the speakers.

Once you have figured out what piece is bad, replace it. If it insists on staying a mystery, sell it as is! OR Sell it with a replacement speaker and let the new owner install it. Remember, time is money and if you ain't having fun, next!

David Houck · « **Reply #8 on:** February 25, 2004, 05:52:13 AM »

Michael; a decent multimeter can be had for $20, which is probably less than the minimum bench time cost at a music store. And they can even be found at hardware stores, which is probably easier than borrowing one from a friend. I carry one around in my gig bag, they don't weigh much and are great for testing batteries.