JBL CBT 70J-1 Review (Constant Beam Transducer)

[Paffi]

Altough I'm probably alone here Maybe someone has an opinion: what do you think would be good rears when using the cbt 70 as front? The cbt 70 are to big and expensive for rear use. Has someone experience with the JBL Control HST?

 

[jhaider]

Altough I'm probably alone here Maybe someone has an opinion: what do you think would be good rears when using the cbt 70 as front? The cbt 70 are to big and expensive for rear use. Has someone experience with the JBL Control HST?

CBT 50 or 100.

 

[sneakmasterG]

CBT 50 or 100.

Also worth noting that you can purchase flush mount brackets for these.

And the CBT 50 were used way back in 2015 as surrounds with JBL M2 mains at CEDIA.

CEDIA 2015 DTS-X and Dolby Atmos Demos Updated

We were pleased with the immersive surround demos by MartinLogan, Paradigm, RBH Sound, JBL and others at CEDIA 2015. We heard the very first DTS:X demos and discuss them in our YouTube video report.

www.audioholics.com

 

[Paffi]

The flush mount is also available for the cbt70, but I think it's expensive for what it is.

I excluded the CBT 50 due the fact that they are broadbands - have they been measurement somewhere?

Ah and maybe a dumb question: I was told, that the CBT 70 with the many tweeters produce a lot of interferences at the highs - but wouldn't that be shown in the measurements, e.g. with vertical directivity errors?

 

[jhaider]

The flush mount is also available for the cbt70, but I think it's expensive for what it is.

I excluded the CBT 50 due the fact that they are broadbands - have they been measurement somewhere?

Ah and maybe a dumb question: I was told, that the CBT 70 with the many tweeters produce a lot of interferences at the highs - but wouldn't that be shown in the measurements, e.g. with vertical directivity errors?

We use CBT100 for sides and rears in our current immersive setup, and previously used CBT50 side/ CBT100 rear. (Upgraded sides for aesthetics and wanted more volume displacement for Dirac ART.) Front speakers and heights are conventional designs not CBT.

They’re not the finest measuring speakers but IMO are very well suited to this limited role.

 

[Paffi]

Well, as I'm listening also to multichannel music, I think I look for something better. It's a pitty that there is no further information regarding the JBL control hst.

Maybe someone can answer my above question "Ah and maybe a dumb question: I was told, that the CBT 70 with the many tweeters produce a lot of interferences at the highs - but wouldn't that be shown in the measurements, e.g. with vertical directivity errors?" @amirm

 

[jhaider]

Well, as I'm listening also to multichannel music,l

I don’t really do movies. The only reason I care about immersive is music. Do what you want, but IMO CBT up front and point source side/rear is ass-backwards system design.

 

[TimVG]

They’re not the finest measuring speakers but IMO are very well suited to this limited role.

CBT 50s here for surround and heights. They take EQ well

 

[dannut]

HST is great for on-wall multiple-row seating scenario. Think of it as a regular bi-pole speaker that was popular in the non-immersive 5.1 era. But with better SBIR mitigation with that single woofer near the back. On-walls have nasty peak-dip in the 200-400Hz region otherwise, that makes sound thin and 'chesty/boomy' at the same time.
Revel once had a similar speaker with different aesthetic once. Maybe still does?

Either way, if you don't require >140deg coverage, go with the CBT.

Ah and maybe a dumb question: I was told, that the CBT 70 with the many tweeters produce a lot of interferences at the highs - but wouldn't that be shown in the measurements, e.g. with vertical directivity errors?

CBT array doesn't do interference by design. But requires small C-C distance wrt to wavelength. Above 10kHz you do get the main lobe and many side-lobes. Don't worry about it, it gets scattered and absorbed easily.

 

[Paffi]

Either way, if you don't require >140deg coverage, go with the CBT.

CBT array doesn't do interference by design. But requires small C-C distance wrt to wavelength. Above 10kHz you do get the main lobe and many side-lobes. Don't worry about it, it gets scattered and absorbed easily.

Thank you! From the perspective of tonality, cbt 70 probably would be the best - you think the cbt 50 is close enough, although other design? The HST is so neat to install - and much cheaper als the cbt. But probably you are right. The HST is maybe a great atmos speaker for the ceiling. I think I keep the current KEF LSX as surrounds until I can get my fingers on a used cbt.

I didn't understand what you meant with "But requires small C-C distance wrt to wavelength." could you maybe explain without abbrevation?

 

[dannut]

I didn't understand what you meant with "But requires small C-C distance wrt to wavelength." could you maybe explain without abbrevation?

Sure. CBT works in principle with tight driver spacing. CBT70 loses ideal CBT behavior above ~8-10kHz. But also you get narrowing dispersion from the 1" tweeter so the effect of driver spacing is "not great, not terrible". Same thing with the 2" driver on CBT50/100. It is inaudible unless you specifically opt for a weird listening position next to and under the speaker and move your head so to be inside the side-lobe. Even then an array-type/CBT speaker is ideally suited for such listening position.

From the perspective of tonality, cbt 70 probably would be the best - you think the cbt 50 is close enough, although other design? The HST is so neat to install - and much cheaper als the cbt. But probably you are right.

Don't worry about tonality in surround music setup (caveats...). Usually surround speaker placement and coverage requirements (angle and falloff wrt distance) are so different to the front 3, that it is better to have dissimilar speakers. Either way - correct speaker type, taking account speaker placement compromises and coverage needs, is much more important. Tonality errors can be corrected after the fact - some form of EQ is mandatory anyways.