Jumping Speakers

[stereo_luver]

While sampling several different amps this weekend I noticed something I rarely look at. Drivers jumping and throwing in their cabinets. While almost everything I was sampling sounded pretty damn good I noticed that different amps caused my drivers to act differently.

Using the same CDP (Mark Levinson #39), Speakers (SDA-2B), Preamp (Macintosh C-20) Bass responce was almost the same.

Amps:

#1. Pair Macintosh MC-75 (Gold Lion KT-88's)......Jumping and smooth
#2. Pair Transcendent 509 (JJ).........................Mild to Snappy
#3. Jolida 801SJ (Tungsol 6550's).....................Min. Movement
#4. Macintosh MC-2205..................................Jumping Nicely
#5. Krell KVA-250...........................................Snap py and Jumping
#6. AR VT100 mkII (Stock)..............................Jumping and Bumping
#7. Pair Fisher AZ-80's (Originals)......................Mid movement

I thought maybe...just maybe the SS would have more of a influence on the movement due to the current...but I found that several tubes did the same. But the sound was always pretty much the same....superb. What gives?

[stereo_luver]

BTW....all listening levels were the same due to different watts per....and I used the same sampling of music for each.

[RuSsMaN]

Ok, so sell me the Fishers. ;)

[stereo_luver]

LOL....KMA man.....BUT....should my bud here in ATL decide to part with his and my being here on the forum be accepted I'll let you know....these are nice units Russ.

[Dennis Gardner]

Too many amps...............too much spare time...................;)

[stereo_luver]

Dennis....you must be Married?....sorry dude...my bad...just kidding.

[Early B.]

Similar concept here....

I don't know if this is true or not, so maybe someone can speak to this, but I assume that, all other things being equal, a driver that displays less movement is a good thing because if the driver is "jumpy," then it is more likely to introduce distortion. Is that correct?

[WilliamM2]

The driver would have to move the same distance to move the same amount of air, and therefore produce the same sound pressure level.

Sounds to me like the different amps were playing at different levels.

[stereo_luver]

Pretty much the same listening levels. Go figure??????

[Jim Shearer]

It seems to me that if you are seeing the cone move, then it must be sub-sonic. I expect that different amps will deal w/ sub-sonic frequencies differently--some may be able to produce them, some not, some intentionally removing them. And for anything below about 18Hz, I want nothing to do w/ it. Spurious signal wasting the amps power & stressing the driver to no good purpose.

Cheers, Jim

[ND13]

Different manufacturers use similar parts and designs, varying in quality and performance, that are better than others at controlling the excursion of mids, mid-woofers, and subwoofers. Typically the better control, the lower the distortion and increased accuracy .