SWR 210 cab "popping"

[LeifVgreens]

Its a long painful story behind all this, but I just got my cab (and head and bass) back from the repair shop (the speakers and my instrument were both distorting independent of one another). The speaker cones on this 210 were actually creasing around the whole speaker about a half inch inward from the surround, as though they were overexerted. To prevent it from spreading, the experienced repair tech at the local guitar shop spread white craft glue over the creases, stating that it would reinforce the cone and not affect the sound. When I got it home and pulled the back plate off myself (before even testing it with the glue), I noticed immediately that the fuse for the tweeter was blown, so I obtained a replacement.

Finally confident that all was well, I plugged it all in and the sound was still wrong. It wasn't distorting as it had been per se, but the drivers in the cab are creating a very distinct "pop" with the impact of every note, rather than the solid punch I'm used to my SWR 210's producing.

A coworker of mine says that it sounds as though the speakers are blown, referring to the magnet structures or coils themselves rather than a torn cone. I still also wonder if this could be the sound of a speaker with glue pasted over the cone, and aside from the glue, the speakers and crossover/everything is otherwise sound. Again, I confirmed with other basses and heads that this cab was distorting before the glue repair and fuse replacement.

Any thoughts?

 

[billfitzmaurice]

They are blown. The creasing was caused by extreme overpowering, as would have been the blown fuse. Once creased there's no fix other than a full recone.

 

[David Jayne]

What Bill said, sorry. You must have SERIOUSLY hammered that thing to blow the tweeter fuse. What on earth were you powering it with?

 

[LeifVgreens]

SWR Workingpro 400 head. I've got an old Goliath Jr. II (4 ohm) where the dust cover started coming off of the cone, and the recently acquired Goliath Jr. III, which is the one with the blown fuse and creasing cones. I got the newer one because its 8 ohms, which means I can pair it with another 8 ohm cab for a full stack running at 4 ohms, which is ideal for the head as its 400watts at 4 ohms.

The first one blew out (dust cover lifting and coils/structures blowing) during a show where I only used that cab and the head with the volume around noon (maybe the bass controls were a bit high, but not extreme). But for all my speakers to be blowing like this, I swear there's something wrong with my head that my instrument might have caused, because my active Fender P Lyte was distorting independent of everything else.

The second Goliath Jr? I got it in the mail used from Guitar Center, noticed the creasing after playing it in the bedroom for 10 minutes, and heard the horrible sound of blown farting speakers at its first time around at band practice. Maybe it was shot when it came to me, but the other 210 blew shortly before. What could a 400 watt amp possibly be pumping out of a single speaker output that could blow these things like this? Bad current? Something that shouldn't be in the signal? DC feedback? The head seemingly sounds alright when I plug it into other cabs at the guitar store...

The Fender P Lyte has been through the shop, faulty volume pot replaced and output tested (only afterwards) for DC current. It's supposedly safe to play, the tech says there's nothing else the bass could possibly be doing to damage an amp. Funny thing here—even my Acoustic 100w combo I bought 2 months ago sounds just like the SWR cabs now.

 

[David Jayne]

Hmm...well, SWR heads are known to be bottom heavy and midrange light. This has the effect of forcing you to turn up louder than usual to be heard. I see this head has something called 'Bass Intensifier' circuit as well. Is that on? Probably not a good idea when using one small cab. I suggest you flatten the EQ, run Bass at noon, Aural Enhancer at 1:00- 2:00. And do engage the Limiter- this is a speaker saver. If the amp doesn't sound 'loud' or 'punchy' enough, try adding low Mids- Mid Freq control mostly or fully counter-clockwise, increase Mid Level a bit.
It is possible there is something actually wrong with the amp, but I doubt it. Try this- turn it on, then plug in a speaker while watching the speaker cone. It should not move at all. If it does(moves in or out a bit and stays there)your amp has a DC offset condition which must be corrected by a tech. DC offset will kill speakers.

 

[billfitzmaurice]

What could a 400 watt amp possibly be pumping out of a single speaker output that could blow these things like this?

The average ten inch driver will not take more than 75 watts before reaching xmax, beyond which they will go no louder. Many will not take more than 150 watts before reaching the point of mechanical damage. And most 400 watt rated amps are capable of delivering at least 600 watts when pushed hard. I'd imagine the cab you got used was blown when you got it. That would explain why it was traded in.

 

[BurningSkies]

You really sound like you need more speakers, or bigger speakers with a larger excursion limit.

 

[LeifVgreens]

The newer 210 in fact continued to distort horrendously, and I've returned it to Guitar Center. I've an SWR 550x (dear god) to be picked up from the repair shop soon, where I can ask the guy to do a couple quick tests on my WorkingPro's outputs. Planning on replacing the 10's in my pre-Fender Jr II cab so that it will be an 8 ohm box instead of 4, then I can pair it with my 8 ohm Big Ben whenever the venue's size allows for it. I've been recommended JBL or EV drivers, and so far have read that EV's hold a reputation for handling lows better and for being more reliable in the long haul—the trade off being that they are a little "sterile" in character compared to JBLs.

Thanks everyone for the input!

 

[billfitzmaurice]

I've been recommended JBL or EV drivers,

JBL and EV dropped out of the electric bass driver market about ten years ago. Neither ever made a dedicated electric bass ten.

 

[RickenBoogie]

What the op needs is more, and/or bigger spkrs. A 210 is not going to get you loud, ever. Think 410 as a bare bones minimum.

 

[DWBass]

The average ten inch driver will not take more than 75 watts before reaching xmax, beyond which they will go no louder. Many will not take more than 150 watts before reaching the point of mechanical damage. And most 400 watt rated amps are capable of delivering at least 600 watts when pushed hard. I'd imagine the cab you got used was blown when you got it. That would explain why it was traded in.

+1

My experience with a SWR Goliath Jr. is they can only get so loud and won't get any louder! It had the same volume whether I used a 100w GK MB150 or a Hartle 5500 pushing 330w into it. It wouldn't budge! I found I would easily blow that cab trying to make it go louder, so I got rid of it.

 

[PawleeP]

They are blown. The creasing was caused by extreme overpowering, as would have been the blown fuse. Once creased there's no fix other than a full recone.

Does uneven porting contribute to much "cone rocking" in a vented 210 and maybe contributing to creasing (besides pumping what i suspect is to much low end). I have seen this on several 10's.. I thing too many players mistakenly think turning all the pre-amp eq knobs to 10 helps their sound.

 

[agedhorse]

Does uneven porting contribute to much "cone rocking" in a vented 210 and maybe contributing to creasing (besides pumping what i suspect is to much low end). I have seen this on several 10's.. I thing too many players mistakenly think turning all the pre-amp eq knobs to 10 helps their sound.

Probably not, but over-powering is most is at certainly a common cause.

It's especially common with 4 ohm 210's, and amps that have higher rated power into 4 ohms.

 

[808State]

People argued over cone rocking as it was believed to only be caused by 2 forces.
Mass and BL. Basically the cone if unbalanced or motor current if unbalanced.

Its obvious its root cause is non symmetrical forces.
That cant be argued.

Either non symmetrical irregularities in the cone itself.
Basically unbalanced cone from manufacturing , uneven glue weight.
etc etc. Basically mass that can change center of gravity.

Non symmetrical irregularities in the magnetic field. or BL
Usually only found at high excursion " huge surprise"
most of it related to the Current of the motor changes at impedance peaks.
Actually more related in reality to the suspension.
And the motor current is just relative.

So most rocking was contributed to driver defects or motor magnet field.
But eventually agreed it had do do with non symmetry of the suspension.
More to do with stiffness and how well the driver can recover from rocking.
Not a suspension defect.

Yabba Yabba. Basically suspension, mass and BL can all contribute to it.
Most of it is complicated waveforms its producing, and asymmetrical pressure.
But yes as " tested" with a pure sinewave. If you deliberately put mass on the cone.
yep it will rock. And if you use out of phase magnets to screw with the BL...yep it will rock.

All speakers any size will cone rock. Its just more a issue in live sound with larger
drivers. Since a larger cone is harder to control. If the cone rocks to much
you can get voice coil rub and poping and various other ugly noises when a coil smacks the gap.

As far as " defects" with speakers and actual mass contributing to rocking.
You see that mainly way way way at the opposite end with tiny speakers.
like headphones and tiny tiny radios or kids toys. Has more to do with the way tiny speakers
are made/ constructed. The likelihood of actually being a weight issue in the cone material or glue process because of small size and the way the cone is made from cheap inconsistent material.

 

[byacey]

All speakers any size will cone rock. Its just more a issue in live sound with larger
drivers. Since a larger cone is harder to control. If the cone rocks to much
you can get voice coil rub and poping and various other ugly noises when a coil smacks the gap.

A coil jumping the gap isn't due to any mechanical or electric irregularities, simply too much power being applied, otherwise the coil would never have left the gap in the first place.

Many pro audio drivers have dual and even somtimes triple spiders to ensure the voice coil is always centered in the gap. It's a tradeoff between efficiency and long term durability.

In my opinion, these 10s failed because they were pushed far beyond what they were designed to do; abused.