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Discussion in 'Speakers' started by AudiocRaver, Oct 26, 2017.
Yes it's really a CD. I can't seem to find a picture on the web.
Yes, the JBL uses a compression driver, crossed over fairly high @1500 Hz.
I like that you said "crossed over fairly high". Only in the world of JBL CD's would 1500hz be called high. I imagine none of the other speakers had tweeters that could cross that low. That's one of the nice advantages of 2 way CD/Waveguide based speakers. A single driver can handle a lot of the range. Like all of the treble and upper midrange. If we can accept that no crossover is perfect and that all crossovers do some harm, then having just one that falls out of our more sensitive region say at 1500hz or below is really handy.
Thanks, it is in fact well identified as CD in the JBL advertising. It must have only been the Klipsch that gave me the dome impression when reviewing the lineup of speakers. I should have double checked before posting.
I'd prefer to see the waveguide handle 1000 Hz on up, it sure is big. Dunno what it's pattern control is below 1500 Hz or if the CD can handle going that low, though.
The crossover point should be set at the place where directivity between the midbass and horn match. Otherwise the directivity is either limited by the waveguide or uneven. This point Is related to both the diameter of the waveguide and the diameter of the woofer. 8" woofers have near 180 degree dispersion up through 1khz and the waveguide, which looks to have an effect width of about 10 inches would only control dispersion down to about 1200hz. That means the crossover has to be set higher, like 1.5khz or the horizontal response will have a variation in the slope between say 1000hz and 1500hz as compared to the rest of the range. There seems to be a misconception on some forums that the waveguide does all the dispersion control. Actually you intentionally want the woofer to be large and have a sloping directivity off axis to blend with the waveguide since that extends the dispersion control down a lot lower. Here is Matt Grants measurement of the Fusion 15 which has a 15" woofer and 15" wide waveguide as an example. The waveguide couldn't control dispersion down past 1khz. It's crossover is 1250hz I believe. You can see smooth directivity control down to 600hz or so. That's because of the directivity of the woofer. Just a wiggle of evidence of the actual crossover at 1250hz. That's how a speaker should be designed.
Yes, we want the crossover just before the woofer starts beaming, handing off smoothly to the waveguide. There are some WG's that can dip down much lower, of course, maintaining directvity almost to Schroeder, which can be useful in smaller rooms. It is a balancing act, one that is often unbalanced by poor dispersion matching between disparate drivers.
No no, that was the oppossite of the point I was making. That's the misnomer. You want to use the change in directivity of the woofer, the beaming, as part of the directivity control. The SEOS 15 has no directivity control at 600hz but the Fusion 15 does. You can certainly do what you say, but then you are mixing big waveguides and small woofers. Why not just use a big woofers and extend the directivity control significantly. QSC actually makes a big deal of this now. I think they call it directivity matches crossovers, something like that. Point is a woofer beaming is a good thing and you want to actually use that quality in the speaker.
I am on board with what you are saying, crossing over where the woofer starts to beam still uses the woofers directivity abilities as the crossover is not a brick wall, but gradual slope into the CD driver. Too high of a crossover starts to leave a hole in the response as the woofer struggles to reproduce frequencies beyond its ability. Please feel free to start a separate thread about this, as it is a topic worthy of its own.
The KEF Q900 evaluation has been posted.
Sonnie (and Wayne)... several years you guys did a Audyssey/Dirac comparison. If I'm not mistaken, your conclusion was that you had a hard time hearing any difference between the two? You'll have to correct me if I'm wrong... anyhow, wondering if that's since changed?
I don't remember enough about it to say... been too long ago. I know I did not know nearly as much about using DL then as I do now. Wayne might can elaborate more. I don't currently have Audyssey, but the last time I did (about 6 months ago) and was comparing the two, I could definitely tell a difference, but Audyssey also did not seem to do near as good of a job with the response as Dirac Live has been doing. I know years ago I was getting a better looking response from Audyssey than I can today. The last measurements with Audyssey did not look anywhere near as good as they do with Dirac Live. It may be as simple as the fact that I use to apply 1/3 octave smoothing with Audyssey, so it always looked good. At 1/12th smoothing that we use now, it doesn't look anywhere near as good, but it looks good with DL. I may have another Denon in here before too much longer, so perhaps we'll travel down that road again.
The Polk S60 report is now online.
We were being very cautious in our approach comparing the two technologies and products. Initially, that approach was to keep the two on an equal apples-to-apples footing, and compared in that way there was not a dramatic difference between the two. We soon realized that we were basically tying one arm of Dirac Live behind its back. Allowing Dirac to really "do its thing as designed," including the use of custom target curves, Dirac Live Unleashed sounded better hands down, and required a lot less fiddling with the mic setup pattern during calibration. Time after time we heard users say their first Dirac Live calibration gave better SS&I results than they ever had with Audyssey after hundreds of calibrations worth of Audyssey experience, and our findings matched that experience, so we declared Dirac to be the EQ tool of choice and, as one convert put it, "never looked back."
The Scansonic M9 evaluation has been posted!
The SVS Prime Tower evaluation has been posted! That is the last of them! A few final thoughts to be added tomorrow.
Awesome write ups!
Thanks Todd... it was really a lot of fun. I can't wait until we do it again!
All the posts are finished!, including a few SUMMARY AND APPRECIATION THOUGHTS. Until Next Time!
Awesome work guys. It was an enjoyable read as usual. I expected the Chane to perform. But I am also intrigued by the Emotiva. That's the fun of reading these things - discovering a new speaker to put on my radar. I'm sure this speaker discovery is a large part of the fun for you guys too. Looking forward to the next one. Do you have a product category and/or price range in mind?
Great job, guys. Lot's of great information.
I am thinking we discussed a $2500 and under range for the next evaluation.
Great reviews guys. The SVS seemed to have really performed. It's measurements look great as do your subject views. That is one I was very curious about. I'd never seen a good review of them before.
The surprises are the funnest parts of these events. Except for the great food and company.
Some speakers may be considered warm in that they tend to make bad recordings sound a bit better. Neutral to bright speakers are more revealing in that they play the material exactly as recorded and they can sound a tad harsh or clinical on poor recordings. I'm very interested in the Chane's and Emotiva's, but I'd really like to hear your thoughts on any of the speakers in regards to these qualities.