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:
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:
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:
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:
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:
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:
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:
Working on refining my distortion graphs, here is a set at two different magnification levels:
And here is the waterfall for those you love to see this pretty graph:
Advanced Speaker Measurements
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.
------------
As always, questions, comments, recommendations, etc. are welcome.
I was hoping to become filthy rich on the backs of your donations. Sadly, that has not happened. So please dig deeper in your pocket and donate the maximum you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
While not much prettier than the next budget speaker, the CBM-170 is a larger and seemingly fancier packaging:
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:
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:
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:
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:
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:
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:
Working on refining my distortion graphs, here is a set at two different magnification levels:
And here is the waterfall for those you love to see this pretty graph:
Advanced Speaker Measurements
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.
------------
As always, questions, comments, recommendations, etc. are welcome.
I was hoping to become filthy rich on the backs of your donations. Sadly, that has not happened. So please dig deeper in your pocket and donate the maximum you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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