Bad 2235H?

[Loren42]

For the first time I had a chance to crank up the amp and drive the speakers at a loud listening volume, but not so loud as to be uncomfortable. We put on Hector Berlioz's Symphonie Fantastique, which I was stunned at the dynamic range of that CD.

Toward the end of track 5 we had the left woofer make a crack or popping sound, which I assume was the voice coil slamming into the back of the magnet structure.

This surprised me because my amp is only 60 Watts, so I would not think that it was a simple case of over driving it. The right woofer played fine and subsequent tracks on other CDs occasionally did the same thing to the left woofer. So, we backed down the volume.

These woofers had a bad time when they were shipped to me and both cones and the domes in particular got some damage when the plastic tie-wraps that held them together broke enroute. I am now thinking that it may be time to bite the bullet and have them reconed. :blink:

[neanderthal]

For the first time I had a chance to crank up the amp and drive the speakers at a loud listening volume, but not so loud as to be uncomfortable. We put on Hector Berlioz's Symphonie Fantastique, which I was stunned at the dynamic range of that CD.

Toward the end of track 5 we had the left woofer make a crack or popping sound, which I assume was the voice coil slamming into the back of the magnet structure.

This surprised me because my amp is only 60 Watts, so I would not think that it was a simple case of over driving it. The right woofer played fine and subsequent tracks on other CDs occasionally did the same thing to the left woofer. So, we backed down the volume.

These woofers had a bad time when they were shipped to me and both cones and the domes in particular got some damage when the plastic tie-wraps that held them together broke enroute. I am now thinking that it may be time to bite the bullet and have them reconed. :blink:


I just went thru the same deal on two 2235's in one 4350 cabinet, and cost me at the tune of $432.55 to get two of the four 2235's reconed.I didn't have the volume cranked so high you couldn't talk either.They say the 4350's can handle what you can throw at them but I just don't see it happening without costly damage.

[Loren42]

I just went thru the same deal on two 2235's in one 4350 cabinet, and cost me at the tune of $432.55 to get two of the four 2235's reconed.I didn't have the volume cranked so high you couldn't talk either.They say the 4350's can handle what you can throw at them but I just don't see it happening without costly damage.

That's probably a good way to put it. We were still able to talk to each other. And we did when we heard it.

I am thinking a subsonic filter would be good insurance. At 60 Watts, which is pushing it for my amp, the xmax should not be reached until you get down to 17 Hz according to Bass Box Pro. It's a guess what xmech is, but that must be lower than 17 Hz.

Must have been some serious rumble way down there.

Ah, according to Bass Box Pro Library, xmech is 11 mm or just below 15 Hz at 60 Watts.

[neanderthal]

That's probably a good way to put it. We were still able to talk to each other. And we did when we heard it.

I am thinking a subsonic filter would be good insurance. At 60 Watts, which is pushing it for my amp, the xmax should not be reached until you get down to 17 Hz according to Bass Box Pro. It's a guess what xmech is, but that must be lower than 17 Hz.

Must have been some serious rumble way down there.

Ah, according to Bass Box Pro Library, xmech is 11 mm or just below 15 Hz at 60 Watts.

Yeah I'm going to have to do something but at this point I don't know what.John Vanderslice at Slice speaker said they hit bottom hard and I wasn't no way near having it so loud you couldn't talk.Maybe the subsonic filter is the answer I'll have to look into it.

[Allanvh5150]

Not the voice coil as such, more than likely it is the mass ring hitting the front plate. You definately need a high pass filter on these and maybe some extra watts wouldn't go astray. 60 watts wont offer a lot of control at low frequencies.

Allan.

[remusr]

Dr House here - I would expect it is your relatively small 60wpc amp clipping and not the 2235 bottoming! I had a DH500 clipping into my L100T's and making a click, suspected it was the woofers but it turned out to be the amp - the 12" woof could take more than the DH500's 250wpc rms so I think it unlikely 60wpc is bottoming your 2235. I can put more than my Mac's 350watts into my L300, 4430, 4435's with no issue. "...more speakers are damaged by low power than high power...." Now if you hear it rubbing all the time the 2235 may be damaged but if it clicks at high volumes it is almost certainly your amp. A misleading thing is your volume control as the pre-amp section always has more voltage amplification than needed to overdrive the power-amp section. Most amps I've used start clipping with the control at 12 o'clock - what appears to be 1/2 volume is in fact enough pre-amp output to overdrive your power amp.

[neanderthal]

Dr House here - I would expect it is your relatively small 60wpc amp clipping and not the 2235 bottoming! I had a DH500 clipping into my L100T's and making a click, suspected it was the woofers but it turned out to be the amp - the 12" woof could take more than the DH500's 250wpc rms so I think it unlikely 60wpc is bottoming your 2235. I can put more than my Mac's 350watts into my L300, 4430, 4435's with no issue. "...more speakers are damaged by low power than high power...." Now if you hear it rubbing all the time the 2235 may be damaged but if it clicks at high volumes it is almost certainly your amp. A misleading thing is your volume control as the pre-amp section always has more voltage amplification than needed to overdrive the power-amp section. Most amps I've used start clipping with the control at 12 o'clock - what appears to be 1/2 volume is in fact enough pre-amp output to overdrive your power amp.

On my 4350's Iam running a Crown K2 for the lows which is driving a 4ohm load on the bottoms of the 4350's and that is 800watts coming from the K2 and and a low still talkable level I rattled out two freshly reconed 2235's.Iam thinking either going to a MA5002vz which is 2000watts driving a 4ohm load or getting another K2 and bridging them so they will kick out 2500watts for a little more headroom than the 800 I now have

[Loren42]

Dr House here - I would expect it is your relatively small 60wpc amp clipping and not the 2235 bottoming! I had a DH500 clipping into my L100T's and making a click, suspected it was the woofers but it turned out to be the amp - the 12" woof could take more than the DH500's 250wpc rms so I think it unlikely 60wpc is bottoming your 2235. I can put more than my Mac's 350watts into my L300, 4430, 4435's with no issue. "...more speakers are damaged by low power than high power...." Now if you hear it rubbing all the time the 2235 may be damaged but if it clicks at high volumes it is almost certainly your amp. A misleading thing is your volume control as the pre-amp section always has more voltage amplification than needed to overdrive the power-amp section. Most amps I've used start clipping with the control at 12 o'clock - what appears to be 1/2 volume is in fact enough pre-amp output to overdrive your power amp.

It sounded like someone took the back end of a screwdriver and rapped it smartly on the side of the cabinet.

My instinct was/is that the driver's VC hit something. As another poster stated, it might have been the mass ring smacking the pole of the magnet and the sharp attack of the sound did sound like something of high density smacking against something else of high density.

The amp is a tube amp with KT88s. I would have expected a more graceful clip than a hard smack sound, but I may be wrong.

I built the amp with lots of filter capacitance, so there is plenty of reserve in the power supply to keep transients lively. :)

[Triumph Don]

Help me here. If you rattled out two fresh 2235's, why would you want to more than double the power?


On my 4350's Iam running a Crown K2 for the lows which is driving a 4ohm load on the bottoms of the 4350's and that is 800watts coming from the K2 and and a low still talkable level I rattled out two freshly reconed 2235's.Iam thinking either going to a MA5002vz which is 2000watts driving a 4ohm load or getting another K2 and bridging them so they will kick out 2500watts for a little more headroom than the 800 I now have[/quote]

[herki the cat]

It sounded like someone took the back end of a screwdriver and rapped it smartly on the side of the cabinet. I would have expected a more graceful clip than a hard smack sound,......... :)


Dr House here - I would expect it is your relatively small 60wpc amp clipping and not the 2235 bottoming!

With due respect to everyone responding to Loern42, I am inclined to agree with Member "remusr," that the amplifier is clipping. You can sort this out by playing your CD precisely at the "Smack level" spot with the same speaker__substituting a load resistor for the speaker will not do__and look at the amplifier output with an oscilloscope.

You may see the sudden jump of a clipped flat top dc component due to the amplifier feedback loop becoming disabled, inviting an open feedback loop condition of typically, some 15 db amplifier over drive during this event. You can read the CD player output with the oscilloscope at the "Smack Signal level," then inch up the drive to your amplifier to this level with a signal generator steady state tone.

You can expect 15 or 20 db into saturation to result in a world class "Smack" capable of bottoming the voice coil hard.

Shipping two speakers safely requires two separate boxes with each speaker basket secured to a square piece of plywood with screws, and surrounding each speaker entity with 1 to 2 inch thick sheet polystyrene internally on all six sides of each box. There have been countless events of speakers bolted together basket to basket resulting in the bottom speaker completely demolished by the top speaker "Smacking"__Eh, Loren42__ the bottom speaker in a 4 ft drop to a concrete floor by the carrier.

Consider that the heavy top speaker acts like a sledge hammer trying to de-accelerate to zero velocity in a space of maybe less than 1/16 of an inch striking the bottom speaker , which is equivalent to placing a speaker with the basket facing a cardboard on a concrete floor and smacking the motor back side of that poor bottom speaker with a sledge hammer of the same mass of the top speaker. Always request appropriate packing by any vendor shipping you speakers. You should see what happens to a pair of 32 pound 2440's shipped in a single box..whooee!... Been there!

cheers, herkic the cat

[Loren42]

Help me here. If you rattled out two fresh 2235's, why would you want to more than double the power?


On my 4350's Iam running a Crown K2 for the lows which is driving a 4ohm load on the bottoms of the 4350's and that is 800watts coming from the K2 and and a low still talkable level I rattled out two freshly reconed 2235's.Iam thinking either going to a MA5002vz which is 2000watts driving a 4ohm load or getting another K2 and bridging them so they will kick out 2500watts for a little more headroom than the 800 I now have[/QUOTE]

The only advantage would be a higher damping ratio, but I agree, no need for higher wattage.

The crown claims a damping factor of only 3,000. :applaud:

The MA5002vz is rated at 1,000. So, I can't see the advantage of the MA5002vz.

[Allanvh5150]

2235's are renowned for slapping their mass rings. I have 2 pair in my setup with 1000 watts on each pair. Without high pass filters they bottom out real quick. Definately not clipping. The 2235 will go low but you do not need a lot of power at 20hz to make the pop.

Allan.

[neanderthal]

2235's are renowned for slapping their mass rings. I have 2 pair in my setup with 1000 watts on each pair. Without high pass filters they bottom out real quick. Definately not clipping. The 2235 will go low but you do not need a lot of power at 20hz to make the pop.

Allan.

This is as best as it has been explained and right to the point as I like it.So plain and simple I need high pass filters to stop the 2235's from bottoming out.

[neanderthal]

SMKSoundPro posted......This is the same that I have experienced with my 2235's. Slapx3=TURN IT DOWN!


When the 2235's rattled out the volume wasn't as loud as you'd think.I could still talk with no problem.Volume wasn't the cause and if you was here at the time you'd know it to be the truth.

[Loren42]

SMKSoundPro posted......This is the same that I have experienced with my 2235's. Slapx3=TURN IT DOWN!


When the 2235's rattled out the volume wasn't as loud as you'd think.I could still talk with no problem.Volume wasn't the cause and if you was her at the time you'd know it to be the truth.

Audible sound level may not have too loud, but subsonic rumble may have had a lot more energy and thus caused the bottoming out of the woofer.

[neanderthal]

Audible sound level may not have too loud, but subsonic rumble may have had a lot more energy and thus caused the bottoming out of the woofer.

And do you think a high pass filter would eliminate the subsonic rumble or subsonic anything if that's the cause?

[Robh3606]

Originally Posted by Loren42 http://www.audioheritage.org/vbulletin/images/buttons/viewpost.gif (http://www.audioheritage.org/vbulletin/showthread.php?p=283319#post283319)
Audible sound level may not have too loud, but subsonic rumble may have had a lot more energy and thus caused the bottoming out of the woofer.


And do you think a high pass filter would eliminate the subsonic rumble or subsonic anything if that's the cause?

I have never had the 2235's in my 4344 clones hit their mass rings. The only time I have had that happen is in a B380 clone listening to "Cloverfield" and the cannons in "Master and Comander" at high SPL levels. Never had it happen on any music source only HT as a sub.

Rob:)

[Allanvh5150]

I have never had the 2235's in my 4344 clones hit their mass rings. The only time I have had that happen is in a B380 clone listening to "Cloverfield" and the cannons in "Master and Comander" at high SPL levels. Never had it happen on any music source only HT as a sub.

Rob:)

Hi Rob,

That is exactly the same as my experience. Just pull back below 30hz works. I prefer to leave it wide open though simply for the fact that sometimes I like it real low. Just turn it down a bit.

Allan.

[Loren42]

And do you think a high pass filter would eliminate the subsonic rumble or subsonic anything if that's the cause?

It can not hurt! This circuit (http://sound.westhost.com/project99.htm) should be just about perfect for you. It is tuned for 17 Hz, but you can change it easily enough if you need to.

[neanderthal]

It can not hurt! This circuit (http://sound.westhost.com/project99.htm) should be just about perfect for you. It is tuned for 17 Hz, but you can change it easily enough if you need to.

The link looks good as far as what little I know. This is where I wish I knew or was more technical to be able to put that filter together.As it is I have to pay someone with the knowledge to put it together because my electronic knowledge is basically nil.
I do have common sense though and was able to solder all the cables and hook everything up.

[Loren42]

The link looks good as far as what little I know. This is where I wish I knew or was more technical to be able to put that filter together.As it is I have to pay someone with the knowledge to put it together because my electronic knowledge is basically nil.
I do have common sense though and was able to solder all the cables and hook everything up.

Should not be a problem if you order the PCB. Just buy the components, push them into the circuit board, solder, and clean with acetone of alcohol. You need a power supply, but there are off-the-shelf power supplies you could buy.

Stuff it in a metal box with connectors and you should be good to go. If you have a PC test program like HolmImpulse you can actually test the circuit and see the results graphically.

[neanderthal]

Should not be a problem if you order the PCB. Just buy the components, push them into the circuit board, solder, and clean with acetone of alcohol. You need a power supply, but there are off-the-shelf power supplies you could buy.

Stuff it in a metal box with connectors and you should be good to go. If you have a PC test program like HolmImpulse you can actually test the circuit and see the results graphically.


I'll look into this,it sounds easy enough. I still have to put the 2235's back into the 4350 cabinet I had to get reconed.Too much goin on gettin ready for summer

[Russellc]

Dr House here - I would expect it is your relatively small 60wpc amp clipping and not the 2235 bottoming! I had a DH500 clipping into my L100T's and making a click, suspected it was the woofers but it turned out to be the amp - the 12" woof could take more than the DH500's 250wpc rms so I think it unlikely 60wpc is bottoming your 2235. I can put more than my Mac's 350watts into my L300, 4430, 4435's with no issue. "...more speakers are damaged by low power than high power...." Now if you hear it rubbing all the time the 2235 may be damaged but if it clicks at high volumes it is almost certainly your amp. A misleading thing is your volume control as the pre-amp section always has more voltage amplification than needed to overdrive the power-amp section. Most amps I've used start clipping with the control at 12 o'clock - what appears to be 1/2 volume is in fact enough pre-amp output to overdrive your power amp. By the by, they were reconed 2225H, work done at Slice speakers in KC!

Agreed. I drive the wholly crap out of mine and never, never have I hit the pole piece. Maybe the mass ring came loose? I've had them playing very loud with various amps, 25 watt MC-225, JBL 6230, a 150 watt Mitsubishi Amp, and my DIY 6550/KT-88 amp. Never a problem, tuning varies from 30 hz, ( 2 vents closed on 4507) and 34 Hz (1 vent closed on 4507), never hit anything and no one could barely hear anyone saying anything!

russellc

[Loren42]

By the by, they were reconed 2225H, work done at Slice speakers in KC!

Agreed. I drive the wholly crap out of mine and never, never have I hit the pole piece. Maybe the mass ring came loose? I've had them playing very loud with various amps, 25 watt MC-225, JBL 6230, a 150 watt Mitsubishi Amp, and my DIY 6550/KT-88 amp. Never a problem, tuning varies from 30 hz, ( 2 vents closed on 4507) and 34 Hz (1 vent closed on 4507), never hit anything and no one could barely hear anyone saying anything!

russellc

Did your setup include a filter for sub-sonics?

[Russellc]

Did your setup include a filter for sub-sonics?
NO. Just the passive crossover for the speaker. Box is about 5 cu ft.

russellc

[jbl]

NO. Just the passive crossover for the speaker. Box is about 5 cu ft.

russellc
If you don't play your system at very loud levels with subsonic bass, you can get away without a filter. I have a 15 Hz filter on my Marantz 3650 which should protect my 2235.

[Loren42]

NO. Just the passive crossover for the speaker. Box is about 5 cu ft.

russellc

Vented, I take it?

Where is it tuned?

[rusty jefferson]

I had this issue with my B-380. When I first worked it into my system I was using a Hafler DH-500 that had been internally bridged. I remember a conversation with someone at JBL tech support recommending a Urei subsonic filter. I never got one. I just figured I would only play it so loud. However a couple of years later the power switch on the Hafler crapped out and rather than jury rig it [pre- internet couldn't find parts and my local tech couldn't fix it] I purchased a Parasound HCA-1500A to replace it. Bridged mono still about 600 watts @ 8ohms, but holy crap that B-380 could play twice as loud [stupid loud] and still not make the pop. I don't pretend to understand electronics, but clearly it was the amp not keeping up with the speaker [as they warned in the owners manual]. Only change I made to the system was the sub amp. When I got a second B-380, my local JBL tech hooked me up with a Crest 7000 series pro amp for the subs. About 500 watts per channel and neither ever made a pop. The attachment is from the B-380 manual.

You can rotate the view of this PDF. See the section on "associated equipment"

[Rolf]

Most of these problems (woofer "sparking") is lack of power. With 700W to the woofer; no problem.

[neanderthal]

Most of these problems (woofer "sparking") is lack of power. With 700W to the woofer; no problem.


The Crown K2 pushing a 4ohm load is 800w to four 2235's

[Rolf]

I am talking 700W (8ohm) to each woofer. 800W to four is only about 100W a woofer in 8ohm. Not much.


The Crown K2 pushing a 4ohm load is 800w to four 2235's

[rusty jefferson]

I'm not so sure it's just the watts per woofer, but the quality. The bridged Hafler I described earlier was outputting about 750 watts, but didn't have the headroom [?] of the Parasound [630 watts] or the Crest [only 500 watts]

[Loren42]

I am talking 700W (8ohm) to each woofer. 800W to four is only about 100W a woofer in 8ohm. Not much.

That would depend on how the drivers are wired, but generally, solid state amps put greater power out as the impedance drops.

[4313B]

It is quite easy to hit the mass ring in a 2235H with an improperly built enclosure. The problem arises when DIY folks use the 2235H improperly.

In the JBL B380 enclosure the BX63 "protects" the 2235H below enclosure resonance with its 25 Hz high pass filter. In the JBL Studio Monitors with the 2231H and 2235H, JBL always advocated using a 30 Hz high pass filter and the 5234/5235 had one. In both cases, mass ring issues were minimized as much as possible.

JBL frowns upon the mass ring these days. It is quite unpopular. It was used in the 121, 124, 2203, 136, 2231, and 2235. It is on the same plane as the spider so if one is hitting the mass ring they are also hitting the spider and mechanical failure is imminent.

Like I've said a hundred or more times, the 2235H likes a 4.5 to 5.0 cubic foot box tuned to 30 Hz. Anything bigger and/or tuned lower (especially without a high pass filter) invariably ends in compromised performance.

[spkrman57]

Without the mass rings I believe the 2234 would be more suitable for some higher level applications with very little LF loss compared to the 2235 is the design is done properly.

Ron

[rusty jefferson]

.
In the JBL B380 enclosure the BX63 "protects" the 2235H below enclosure resonance with its 25 Hz high pass filter. In the JBL Studio Monitors with the 2231H and 2235H, JBL always advocated using a 30 Hz high pass filter and the 5234/5235 had one. In both cases, mass ring issues were minimized as much as possible.



Do you think my original [Hafler] amplifier wasn't actually the culprit with my B-380/bx63-a ? I have always assumed that even though it had plenty of power [700 +watts] it couldn't control the driver during those demanding peaks. Again, once I changed to a more modern high current amplifier,[500-600 watts] the spl increased and the speaker never "popped" again.

[4313B]

Do you think my original [Hafler] amplifier wasn't actually the culprit with my B-380/bx63-a ? I have always assumed that even though it had plenty of power [700 +watts] it couldn't control the driver during those demanding peaks. Again, once I changed to a more modern high current amplifier,[500-600 watts] the spl increased and the speaker never "popped" again.Amps that can't control four-inch voice coils are definitely a problem. We've talked about this quite a bit too.

[Loren42]

It is quite easy to hit the mass ring in a 2235H with an improperly built enclosure. The problem arises when DIY folks use the 2235H improperly.

...

JBL frowns upon the mass ring these days. It is quite unpopular. It was used in the 121, 124, 2203, 136, 2231, and 2235. It is on the same plane as the spider so if one is hitting the mass ring they are also hitting the spider and mechanical failure is imminent.

Like I've said a hundred or more times, the 2235H likes a 4.5 to 5.0 cubic foot box tuned to 30 Hz. Anything bigger and/or tuned lower (especially without a high pass filter) invariably ends in compromised performance.

The big difference between the 2234H and 2235H (besides cone mass) is the 2235H gives you an audio warning when Xmech is reached, whereas the 2234H does not annunciate that it is about to self destruct. :D

[Russellc]

If you don't play your system at very loud levels with subsonic bass, you can get away without a filter. I have a 15 Hz filter on my Marantz 3650 which should protect my 2235.
I play it plenty loud. When listening in the garage. (several rooms away)
it will be hitting over 100 db and louder, no problems.

russellc

[Russellc]

Like I've said a hundred or more times, the 2235H likes a 4.5 to 5.0 cubic foot box tuned to 30 Hz. Anything bigger and/or tuned lower (especially without a high pass filter) invariably ends in compromised performance.

This is the recipe I have, JBL 4507/4647 box, between 4.5 and 5 cu ft, with either one (34 hz ) or two (30 hz) of the four vents plugged. Plays loud, nothing hits the pole piece, even when flat Jamming!;)

russellc