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Thread: Bad 2235H?

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    Senior Member Loren42's Avatar
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    Bad 2235H?

    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.

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    RIP 2011 neanderthal's Avatar
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    Quote Originally Posted by Loren42 View Post
    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.

    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.

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    Senior Member Loren42's Avatar
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    Quote Originally Posted by neanderthal View Post
    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.

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    RIP 2011 neanderthal's Avatar
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    Quote Originally Posted by Loren42 View Post
    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.

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    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.

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    Senior Member remusr's Avatar
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    More likely the amp than the woof

    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.

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    RIP 2011 neanderthal's Avatar
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    Quote Originally Posted by remusr View Post
    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

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    Senior Member Loren42's Avatar
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    Quote Originally Posted by remusr View Post
    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.

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    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]

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    Senior Member herki the cat's Avatar
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    Quote Originally Posted by Loren42 View Post
    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,.........
    Quote Originally Posted by remusr
    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
    Last edited by herki the cat; 03-19-2010 at 12:43 PM. Reason: Natha

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    Senior Member Loren42's Avatar
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    Quote Originally Posted by Triumph Don View Post
    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.

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

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    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.

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    RIP 2011 neanderthal's Avatar
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    Quote Originally Posted by Allanvh5150 View Post
    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.

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    RIP 2011 neanderthal's Avatar
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    Re: SMKSoundPro

    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.

  15. #15
    Senior Member Loren42's Avatar
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    Quote Originally Posted by neanderthal View Post
    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.

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