Kef Q100 Drive Unit Testing

[ErinH]

I just finished up publishing data from the Q100 drive unit testing:

http://medleysmusings.com/kef-q100-drive-unit-testing/

Here's a sample...




To those who remembered Zaph saying he'd like to see Klippel testing on the suspension because he believed it would show a shift... well, he was right:






This is my favorite part. I measured the tweeter's response with the woofer at rest, then fixed out via a 9v battery and then fixed in (9v battery again). This was done to see what impact this had on the tweeter's response. Here's a result:

[Face]

Thanks!

[Deward Hastings]

Re: Kef Q100 Drive Unit Testing

Interesting . . . another example of a driver that sounds (maybe) better than it tests.

[jonpike]

Re: Kef Q100 Drive Unit Testing

Interesting results... could you give us an idea what the excursion is? As in, what's the "X9vbatt" when you have it one way and the other? :D

[ErinH]

Re: Kef Q100 Drive Unit Testing

It's hard to say exactly, but it's roughly about 3mm.

[ErinH]

Re: Kef Q100 Drive Unit Testing

For anyone who may be interested, I'll be listing these up for sale sometime soon. I paid about $400 shipped and would like to get that back out of them. Just tossing it out there.

[nigelb]

Re: Kef Q100 Drive Unit Testing

Just wondering if you pulled out the crossover on these? From Zaph's blog post it would seem that it might need very few components. Any chance of a picture or a schematic?

[ErinH]

I can do that.

[djkest]

Re: Kef Q100 Drive Unit Testing

So Klippel testing reveals that the suspension is non-linear? Meaning that it's stiffer moving in one direction than the other? How does this translate into audible performance? Seems like the measurements you took would suggest that this interesting design is not without it's faults. Also, looks like the speaker cone movement mostly influences above 6k with some pretty big suck-out in the 7.5k region.

Thanks for measuring and posting your results.

[ErinH]

The assymetry in suspension is responsible for the higher 2nd order distortion. I know some manufacturers do this on purpose to keep 3rd order down as a trade off.

[clydethecat]

Re: Kef Q100 Drive Unit Testing

So KEF spec lists the Q100 as an 8-ohm system, yet the driver itself says 4 ohms? http://www.kef.com/html/en/showroom/...100/index.html

[ErinH]

Re: Kef Q100 Drive Unit Testing

Just wondering if you pulled out the crossover on these? From Zaph's blog post it would seem that it might need very few components. Any chance of a picture or a schematic?

I updated my site with a picture. Here you go:

[Face]

Re: Kef Q100 Drive Unit Testing

It doesn't get much simpler than that.

[ErinH]

Update:
I've been using these speakers (driver and cabs) as my reference/experimenting setup with dolby, L7, etc recently and I can say unequivocally, these are by far the best set of speakers I've heard in their respective size range. The imaging and soundstage along with vocal acuity is incredible. When I first fired them up I was extremely impressed. Walking around the speakers, there is no dramatic drop in response; the sound power response is excellent.

I had every intention on selling these to get funds back but at this point I'm making every effort to not have to sell them. I'd like to make them my new reference setup. A sub to pick up below 50hz mated to these would make a very potent and worthwhile setup rivaling many tower based setups I've heard. And this is coming from the guy with a set of Zaph ZRT 2.5's. the cool part is its extremely portable so I can take it to meets and demo for others.

Kef really nailed this speaker. For its price I have yet to find anything I think could beat it.


The HTS3001se's I bought to test rival these as well, albeit with less low end output. Overall, Kef has done an extremely good job with their coax design.

[Face]

Re: Kef Q100 Drive Unit Testing

I couldn't agree more. I use a pair in my bedroom rig, no need to try to replace these with a pair of DIY speakers...