Another Speaker Tweak...

[Early B.]

On Brian's advice, I purchased a pair of "upgraded" mid-bass drivers for my VMPS Tower IISE's. There were no crossover changes required and the drivers were reasonably priced, so I decided to roll the dice and go for it. They arrived yesterday, but I was surprised to find that the drivers had foam surrounds and a smaller magnet. At this point I grew more skeptical.

OK, so I popped out the old 12" drivers and soldered the new ones in, then cranked some tunes. I was immediately impressed with the improved separation, detail, and soundstage extension. The sound was almost precisely what I had longed for.

However, there was a significant decrease in bass, and that got me a bit worried. After a quick e-mail to Brian, he told me to pinch some putty (if you don't know what I mean, visit the VMPS website for more info). Again, I was skeptical. So I reached underneath each speaker and took a fingernail full of putty from the passive radiator, then played some music. I was absolutely floored by the result. That tiny little bit of putty nearly restored all of the bass that was lost. Of course, I took another fingernail full and got more bass, then another, and stopped at three putty pulls. Now I have improved detail and separation with the bass intact. Gotta luv it, man.


Lesson for the day -- get yourself some tweakable speakers. End of lesson.

[engtaz]

he told me to pinch some putty (if you don't know what I mean, visit the VMPS website for more info). Where on their website do I find this info.
Congrats on the new sound.

engtaz

[Early B.]

Where on their website do I find this info.
Congrats on the new sound.

Here's a quick explanation -- putty adds mass to the passive radiator to cause it to "cooperate" with the other active bass drivers in such a way as to "react" to them at a lower frequency and different phase. This reaction to the active drivers extends bass response in frequencies lower than the actives, because the Passive Radiator moves slower and in a different phase. If the putty is exactly right, this reaction will "seamlessly" add the lower bass extension. If it is too light or too heavy, it will create cancellation and distortion.

Attached is a detailed explanation...