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Ascend CBM-170 SE Speaker Review

amirm

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This is a review and detailed measurements of the CBM-170, Signature Edition, bookshelf speaker review. It is on kind loan from a member. Despite being produced in US, the CBM-170 is priced quite reasonably at US $384/pair. It is on sale as of this writing for even less at US $298 a pair.

While not much prettier than the next budget speaker, the CBM-170 is a larger and seemingly fancier packaging:

Ascend Acoustics CBM-170 Bookshelf Speaker Audio Review.jpg

It is a classic formula for a 2-way speaker. Sadly, it lacks a waveguide to better integrated the tweeter and woofer at crossover point. Here is the back panel of the speaker:

Ascend Acoustics CBM-170 Bookshelf Speaker Signature Series Back Panel Audio Review.jpg

Not much to complain about in this price range.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections. It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

All measurements are reference to tweeter axis with the grill removed.

Around 500 points around the speaker were measured (from 20 to 20 kHz) which resulted in well under 1% error in identification of the sound field across full frequency response of 20 to 20 kHz. Final database of measurements and data is 750 megabytes in size.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Audio Measurements.png


From a number of listening tests I have performed to correlate measurements to what we hear, I have learned that the baseline for tonality gets set around 200 Hz region. So I drew that line and as we see, the response starts to peak above that starting around 1 kHz and keeps going. As such, I expect the speaker to sound bright.

The problem of a small tweeter and larger woofer without directivity control (e.g. waveguide) is seen above but magnified more when we look at directivity index:

Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Directivity Audio Measurements.png


The dashed blue line is difference between what you hear directly from the speaker and important (loudest) reflections around the room. Ideally these two match each other, sans a gradual reduction in high frequencies which makes the graph point up. Here, the blue line deviates a lot from the straight line meaning the off-axis response is colored relative to direct sound. This makes this bit of advertising from the company strange:

1583183162705.png


Above measurements don't point to accurate sound. And certainly not a benchmark for bookshelf speakers.

We can predict how this speaker will sound by mixing the right ratio of direct and indirect sound from the speaker:

Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Predicted In-room Response Audio...png


Once again we see the extra energy at higher frequencies.

As I note on the graph, this is a good way to sell speakers as at first it sounds much more "detailed." But over time, that extra sharpness can become grating.

We are done characterizing the speaker at this point. The rest is for speaker nerds.

Basic Speaker Measurements
Measurement of the impedance shows a dip to below 4 ohm in bass frequencies so you better have more capable amplification than you think you need:
Ascend Acoustics CBM-170 Bookshelf Speaker Impedance and Phase Audio Measurements.png


Working on refining my distortion graphs, here is a set at two different magnification levels:

Ascend Acoustics CBM-170 Bookshelf Speaker Distortion THD Measurements.png


Ascend Acoustics CBM-170 Bookshelf Speaker Distortion zoomed Measurements.png


And here is the waterfall for those you love to see this pretty graph:

Ascend Acoustics CBM-170 Bookshelf Speaker CSD Waterfall Audio Measurements.png


Advanced Speaker Measurements

Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Early Reflections Audio Measurem...png


Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Horizontal Directivity Audio Mea...png

Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Vertical Directivity Audio Measu...png


Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Full Horizontal Directivity Audi...png


Ascend Acoustics CBM-170 Bookshelf Speaker CEA-2034 Spinorama Full Vertical Directivity Audio ...png


Ascend Acoustics CBM-170 Bookshelf Speaker Horizontal Contour Audio Measurements.png


Ascend Acoustics CBM-170 Bookshelf Speaker Vertical Contour Audio Measurements.png


Speaker Listening Tests
Even though this is not sold as a near-field speaker, I have a better setup on my desk to perform AB comparisons. I compared the CBM-170 SE against the Pioneer SP-BS22. Despite being a larger speaker and hence has more bass, the dominant impression of the Ascend speaker is that it is bright. It sounds "detailed" to be sure but will give you a shave if you let it. If you are using this speaker without broad EQ, then I think you will get tired of its sound very quickly after the initial "high."

To be clear though, it has much better power capability than the Pioneer so the Pioneer doesn't win on all factors.

One disappointment was the amount of cabinet flex and resonance. There was a ton of it with Ascend, matching the same amount of the much cheaper Pioneer.

Conclusions
You are paying a premium for a US made speaker here, with possibly better parts. Overall though, the excess energy in high frequencies combined with some directivity issues is problematic. I suggest looking elsewhere for a better design. As is, there is not much to get me excited about the Ascend CMB-170 SE so I am not going to recommend it.

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

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Attachments

  • Ascend CBM170 Spinorama Data.zip
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'Textbook' design - not sure what the woofer is (looks to be a well damped cone of some kind), vifa/peerless sub-20 dollar tweeter. Optimized for flat on-axis response, which it achieves, at the expense of off-axis. Port looks small, much smaller in diameter than the other Ascend reviewed; may not be a factor.

For 300 dollars in nearish field or in the right room these would be a good deal for a traditional made in the USA speaker. Harmonic distortion appears to be pretty low.
 
For 300 dollars in nearish field or in the right room these would be a good deal for a traditional made in the USA speaker.

Personally, I think their on axis response looks pretty decent. They very look nicely made, well finished, and don't cost the earth.

The fact that they sound a bit bright compared to those hideous Pioneers is a good thing- the BS22s are rotten, with their signature "someone threw a wet blanket over the speakers" sound.
 
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Is there going to be a review of the Sierra-1 as it's still one of their best selling speakers?
 
What a horrible sounding speaker. It should never have become the de facto studio standard it once was.

They aren't horrible at all. They are a small, tough, well made compact speaker that was used, manufactured and supported with parts for decades in a consistent way by a respected manufacturer all at a very reasonable price.

No wonder they became the defacto standard. And well deserved. The modern fashion of p#ssing all over a product which essentially defined an entire genre of compact near-field speakers is tiresome.

Can you imagine all the fly-by-night, one hit wonder companies these days being able to achieve consistency for several decades? No chance. They'd blame their supply chain inconsistencies, the cone material manufacturer, the lack of quality cabinet material, whatever excuse. Yamaha just built every key part, from scratch, in heir own factories for decades.
 
I'm really glad to have found this website. Lots of speakers that have been reccomend to me have ended up being horrible. It's really nice to see these internet direct speakers finally being tested. I was originally told these 170's are comparable to my Phil harmonic AA's and that the 170 center would be a close match but this test proves my AA's are better and much cheaper. Thanks for whoever loaned these amirm.
 
I'm really glad to have found this website. Lots of speakers that have been reccomend to me have ended up being horrible. It's really nice to see these internet direct speakers finally being tested. I was originally told these 170's are comparable to my Phil harmonic AA's and that the 170 center would be a close match but this test proves my AA's are better and much cheaper. Thanks for whoever loaned these amirm.
There haven't been measurement of your AA's to compare to yet. Send them in!
 
Just a bit of tidbit which will also hopefully provide some context to this speaker review - according to this forum post, this speaker was released in early 2006 - a whopping 14 years ago (I did the math)!

Perhaps the manufacturer's marketing language, that @amirm takes objection to, rang truer at the time? :)
 
'Textbook' design - not sure what the woofer is (looks to be a well damped cone of some kind), vifa/peerless sub-20 dollar tweeter. Optimized for flat on-axis response, which it achieves, at the expense of off-axis. Port looks small, much smaller in diameter than the other Ascend reviewed; may not be a factor.

For 300 dollars in nearish field or in the right room these would be a good deal for a traditional made in the USA speaker. Harmonic distortion appears to be pretty low.

SEAS tweeter actually, 27TDFC or a variant thereof.
 
Seems okay for the price, lots of good stuff now in this range but nearly all of it is made in China. Nothing against China but having a USA made product at this price point that performs alright is pretty legit.
There is no chance I am buying these but maybe some folks will appreciate the sound signature, some folks like bright.
 
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