Ascend CBM-170SE2 Speaker Review

[thewas]

On DIYaudio this used to be (and still is in a lot of builds) an important factor in good speaker and crossover design.

Yes, I also use such on my own DIY wide radiation designs (so mainly 3-ways with small diameter drivers like dome mids).

 

[Matt_Holland]

Off course you can, that is an old trick, matching the directivity of the tweeter and woofer by choosing the right crossover point and slopes (so the transition is smooth). It's a bit a lost art in times of waveguides i have the impression, but it used to make the difference between good and bad speakers. On DIYaudio this used to be (and still is in a lot of builds) an important factor in good speaker and crossover design.

Is it also true that you need to consider baffle edge diffraction in the tweeter off-axis response?

I’ve seen on many GR Research upgrade videos where there is an attempt to improve directivity by lowering the crossover point. However what usually results is a persistent off-axis peak in the region of 2-5KHz, presumably related to the baffle width diffraction effect?

So the balance is going as low as you can in terms of crossover frequency, but not so low that baffle edge diffraction becomes too serious an issue. Wider baffles might help?

The benefit of a WG is not just to match woofer-tweeter directivity and the xover point, but to “hide” the cabinet edges from the tweeter, thereby removing many edge diffraction effects.

We also see manufacturers like Revel, KEF and Ascilab use tweeter “phase plugs” to widen tweeter dispersion at very high frequencies.

All that being said, what the CMB-170SE achieves at its price point is remarkable.

​

 

[Waxx]

Is it also true that you need to consider baffle edge diffraction in the tweeter off-axis response?

I’ve seen on many GR Research upgrade videos where there is an attempt to improve directivity by lowering the crossover point. However what usually results is a persistent off-axis peak in the region of 2-5KHz, presumably related to the baffle width diffraction effect?

So the balance is going as low as you can in terms of crossover frequency, but not so low that baffle edge diffraction becomes too serious an issue. Wider baffles might help?

The benefit of a WG is not just to match woofer-tweeter directivity and the xover point, but to “hide” the cabinet edges from the tweeter, thereby removing many edge diffraction effects.

We also see manufacturers like Revel, KEF and Ascilab use tweeter “phase plugs” to widen tweeter dispersion at very high frequencies.

All that being said, what the CMB-170SE achieves at its price point is remarkable.

​

True, that's why i studied the subject. Waveguides bring a lot of advantages to the table.

 

[GavriloD]

@amirm @AscendDF

We need a review of CMT-340SE2

 

[UK Sugden Fan]

This is a review, listening tests and detailed measurements of the Ascend Acoustics CBM-170SE2. It was sent to me by the company and costs USD $248 each. $468 a pair.
View attachment 549277
There is a grill which I removed, making the speaker look utilitarian. Pick it up though and you realize it weighs more than you expect.

Love the mention of NFS Optimized text on the label:
View attachment 549278

Ascend CBM-170SE2 Speaker Measurement
As noted, I stripped the speaker off its grill and measured it with Klippel NFS using the tweeter center as the reference:
View attachment 549279

As noted, the general on-axis response is flat as we like. There are however some variations including a resonance around 900 to 1000 Hz and some slight shortfalls in treble region. The listening window though (dashed green) is smooth. Early window reflections sum well, indicating optimization in this regard:
View attachment 549280

All of this sums to a surprisingly good predicted in room response:
View attachment 549281

I know this is a major focus area for Dave (the designer).

Near-field response shows some of the unevennes of the tweeter:
View attachment 549282

I expected to have to baby the speaker during my power sweep but that was not so as it easily played even the 96 dBSPL signal without complaining:
View attachment 549283

View attachment 549284

Notice how much lower the distortion is at 86 dBSPL across the full frequency range! It wasn't until I got to 101 dBSPL that I heard some distortion at the start of the sweep:
View attachment 549285

There is no waveguide so we have natural beaming from the tweeter:
View attachment 549286
The benefit is wider dispersion at lower treble.
View attachment 549287

Vertical response is as we expect from 2-way speaker so best to stay at tweeter axis:
View attachment 549288

Impedance is about average around 3.5 ohm:
View attachment 549289

We have the usual resonances:
View attachment 549290

But clean step response:
View attachment 549291

Ascend CBM-170SE2 Speaker Listening Tests
As Dr. Toole is fond of saying, sometimes graphs bother the eyes more than the ears. Such is the case here if you look at the on-axis response. I was fully ready to have to add some small touches with EQ but none was needed whatsoever. The speaker played clean and loud with a level of fidelity that belied its looks and certainly its price. Indeed, the price has nothing to do with it. My reference tracks, one by one, impressed with no excuses needed to be made. Closing my eyes, I perceived a very large spatial image that helped in that regard. I am talking about a bubble that was 6 feet or more around and above the speaker! With a pair, the CBM-170SE2 will fill a large stage with delightful tonality and accuracy.

My sub-bass heavy track didn't bother the speaker one bit as it simply rolled it off instead of playing and getting distorted.

Conclusions
For less than $500 you get a speaker built in US that brings tears to your eyes as far as fidelity and enjoyment. This is what we get when we put the right tool, Klippel NFS, in the hands of the a skilled designer. "Measure it and will get better" and better it did. The only compromise is not playing very low which you wouldn't expect it to. Power handling is excellent as a result. Nothing like going into a review and expecting one thing, and getting handed something far better. Ascend breaks new ground here with this level of performance for so little money.

The Ascend Acoustics CBM-170SE2 is an easy strong recommendation from me.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

On the label it says "Acoustic Suspension" but it has a reflex port so it isn't according to my understanding. Still seems like a good one.

 

[Matt_Holland]

On the label it says "Acoustic Suspension" but it has a reflex port so it isn't according to my understanding. Still seems like a good one.

Answered by the manufacturer in post #55

 

[pathtonowhere]

I really don't like the dispersion, no matter how flat the on axis and in room response. How hard is it to fit a little waveguide?

 

[PristineSound]

I really don't like the dispersion, no matter how flat the on axis and in room response. How hard is it to fit a little waveguide?

What specifically about the dispersion you don't like?

Ascend 's design philosophy is very wide dispersion, hence they are hesitant with waveguides as it will restrict the dispersion.

 

[YouDontHaveEnoughBass]

It would be more room dependant than a speaker with smoother dispersion but at this price point I can’t complain, it’s achieved everything it set out to do spectacularly well

 

[tw 2022]

What specifically about the dispersion you don't like?

Ascend 's design philosophy is very wide dispersion, hence they are hesitant with waveguides as it will restrict the dispersion.

Same with Philharmonic audio, and lots of folks, including me, like the soundstage width and depth... I love a clear center image as well , but I'd rather sacrifice a little there rather than the expansive soundstage...

 

[PristineSound]

Same with Philharmonic audio, and lots of folks, including me, like the soundstage width and depth... I love a clear center image as well , but I'd rather sacrifice a little there rather than the expansive soundstage...

I'm the reverse, I'm ok with sacrificing some soundstage for a dead phantom center.

But in the end, neither is a bad choice to sacrifice for the other. Not to mention the Ascend has excellent imaging along with an explosive soundstage anyway.

 

[tw 2022]

I'm the reverse, I'm ok with sacrificing some soundstage for a dead phantom center.

But in the end, neither is a bad choice to sacrifice for the other. Not to mention the Ascend has excellent imaging along with an explosive soundstage anyway.

That's the beauty of this hobby.. Lots of ways to get " there "....and none are wrong...from $500 set ups to 5 figures... It's about fun and learning how to set up the best experience for yourself...

 

[amirm]

I really don't like the dispersion, no matter how flat the on axis and in room response. How hard is it to fit a little waveguide?

It is a 3-d part that has to be produced somehow which goes against trying to create a budget product. Without it you are just screwing drivers to wood.

 

[Michou]

The new CBM-170SE2 seems to measure exceptionally well, and Ascend deserves credit for putting so much engineering into a speaker at this price.

That said, at around $500/pair, the competition is pretty strong. You are up against speakers like the ELAC DBR62, Wharfedale Diamond 12.2, Polk ES20, Starke Sound Beta 5, Acoustic Energy AE100 MkII, and the KEF Q350 when it goes on one of its frequent sales.

So beyond the measurements, what does the CBM-170SE2 really bring that these speakers don't?

Is it noticeably better in terms of dynamics, bass, imaging, or overall musical involvement? Does it have a particular strength that makes it stand out, or is the main advantage simply its excellent measured performance?

One thing that does set Ascend apart is the philosophy: put the money into the drivers, crossover and engineering rather than cosmetics. That is a perfectly valid approach, but compared with many competitors, the CBM-170SE2 is a fairly plain-looking speaker. ELAC, Wharfedale, KEF and others generally offer more attractive cabinets and finishes that may fit better in a living room.

There is also the practical issue that many of these alternatives can be seen and auditioned at a local dealer before buying. With Ascend's direct-sales model, you are mostly buying based on measurements, reviews and the return policy.

No doubt it is a technically impressive speaker. I'm just curious what owners feel it does better than the many very capable options already available around the same price.

 

[YouDontHaveEnoughBass]

Directivity is less about imaging for me and more about tonality in reflective rooms - that 2-6khz ballon in horizontal dispersion on less well designed flat baffle speakers tends to lead to a harsh sibilant sound in my room and trying to fix with EQ just leads to a noticeably weird on-axis

This is a pretty common problem in modern apartments and the like

 

[TurtlePaul]

So beyond the measurements, what does the CBM-170SE2 really bring that these speakers don't?

Is it noticeably better in terms of dynamics, bass, imaging, or overall musical involvement? Does it have a particular strength that makes it stand out, or is the main advantage simply its excellent measured performance?

No doubt it is a technically impressive speaker. I'm just curious what owners feel it does better than the many very capable options already available around the same price.

Nobody owns there yet. They are new.

Your 'beyond measurements' criteria is a stretch. The 8.2 no EQ with sub preference rating IS going to be one of the main selling points. It is better than the best of the listed speakers by about a half point, which is quite significant. The good SPL/distortion for the class is another selling point. The measurements are the sound.

I agree that it would be great if they offered a faux walnut or gloss black finish options - even if they are still vinyl wraps.

The weak point of these speakers is the bass. 'Imaging', 'dynamics', and 'musical involvement' are the measurements. If a speaker has good measurements, it has good sound.

 

[Hifihedgehog]

Nice to have another good speaker to recommend to someone on a budget. I know we throw around 4+ figure price tags around here like it's normal, but for most people $500 speakers count as high end. Good that they can get sound that deserves the label too.

Indeed, and it will outperform a good deal of many of the so-called "high-end" snake oil that is peddled around for 10 times that price, easily. I can only imagine what Ascend Acoustics will be churning out in the next decade with the price to performance being so exceptional already for such a low asking price.

 

[Karmacoma]

It is a 3-d part that has to be produced somehow which goes against trying to create a budget product. Without it you are just screwing drivers to wood.

Probably, and that's too bad cos intuitively most people buy small "budget" speakers for small spaces, and the waveguide is a real plus in that case imo.

 

[amirm]

You are up against speakers like the ELAC DBR62, Wharfedale Diamond 12.2, Polk ES20, Starke Sound Beta 5, Acoustic Energy AE100 MkII, and the KEF Q350 when it goes on one of its frequent sales.

Commenting on Elac, it is $800 a pair now so much more expensive. It looks nicer but has rougher response compared to Ascend.

 

[amirm]

There is also the practical issue that many of these alternatives can be seen and auditioned at a local dealer before buying. With Ascend's direct-sales model, you are mostly buying based on measurements, reviews and the return policy.

It is less than $500 with return policy. So it is not much of an inconvenience to try it at home. It is small and easy to ship back if you don't like it. I don't even know where I would go to listen to budget speakers where we live. Bestbuy is an hour away each direction and that is it. Much more convenient to buy online and try.