Ascend CBM-170 SE Speaker Review

[AscendDF]

No, I used those to upgrade my Sierra-1's. There's more than one way to buy crossovers and I didn't acquire those from Madisound (obviously). I just wanted to assuage those losing sleep over my xover issue. The open hostility is not appreciated, not a good look, and hopefully will not be tolerated at ASR like it is other places.

Understood, but those Sierra-2EX crossovers are designed to "see" Sierra-2EX drivers only and only within the Sierra-2EX cabinet. I want to make sure you understand this. It is very precise, even a change in baffle size, or driver to driver spacing requires crossover changes. This is critical with a speaker like the Sierra-2, because the high pass and low pass filters do interact with each other and it is possible that simply swapping in a different woofer could result in lowering the crossover point which could end up causing unwanted frequencies to reach the ribbon tweeter, possibly resulting in damage.

Obviously, you have a great interest in speaker design and I encourage you to continue experimenting. There are many good books out there that you can learn from with regard to crossover design and how to best match and "pick" off-the-shelf drivers to reach the performance goals you are after for your design. The ability to take proper measurements is critical though, and without that - even though to your ears something might sound better, expectation bias is real. Since you believe in measurements, I had previously offered to measure one of your modified speakers on our NFS free of charge (you are responsible for shipping) - that offer still stands. Companies often pay up to $2K for this type of service.... Wouldn't you like to "see" the performance of your creation?

 

[BDWoody]

No, I used those to upgrade my Sierra-1's. There's more than one way to buy crossovers and I didn't acquire those from Madisound (obviously). I just wanted to assuage those losing sleep over my xover issue. The open hostility is not appreciated, not a good look, and hopefully will not be tolerated at ASR like it is other places.

Not seeing open hostility, although your own posts come pretty close. Not sure why the attitude, but you can dial it back a bit.

Thanks, but I really wasn't asking for opinions.

This is an open forum. Opinions are what you are going to get.

 

[tw 2022]

Actually, it hasn't. When I was swarmed over at AVS by the g-squad (someone else's characterization by PM) I never indicated that. So, please speak for yourself.


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sorry , i read your conversation ( with Dave from ascend) at avs... it seemed pretty clear that you weren't doing crossover and/ or cabinet mods.. my apologies , i stand corrected...

 

[beagleman]

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.

Found this older review just to see the "results", as I just recently heard the CMB-170's at a friends house, and oddly can not agree more.

I have heard the Pioneer 22's and they are semi dull sounding, but found the Ascent 170 SE in all honesty to sound quite neutral, with perhaps only a tiny tiny bit of brightness but mostly when up close. ...but far less than speakers I think we all agree truly sound "Bright" in caps.

Not saying they were the "Final word" on sound, but for the price, and made in USA, hard to really find many faults.

 

[beagleman]

Understood, but those Sierra-2EX crossovers are designed to "see" Sierra-2EX drivers only and only within the Sierra-2EX cabinet. I want to make sure you understand this. It is very precise, even a change in baffle size, or driver to driver spacing requires crossover changes. This is critical with a speaker like the Sierra-2, because the high pass and low pass filters do interact with each other and it is possible that simply swapping in a different woofer could result in lowering the crossover point which could end up causing unwanted frequencies to reach the ribbon tweeter, possibly resulting in damage.

Obviously, you have a great interest in speaker design and I encourage you to continue experimenting. There are many good books out there that you can learn from with regard to crossover design and how to best match and "pick" off-the-shelf drivers to reach the performance goals you are after for your design. The ability to take proper measurements is critical though, and without that - even though to your ears something might sound better, expectation bias is real. Since you believe in measurements, I had previously offered to measure one of your modified speakers on our NFS free of charge (you are responsible for shipping) - that offer still stands. Companies often pay up to $2K for this type of service.... Wouldn't you like to "see" the performance of your creation?

Having dabbled in actual speaker "Design" back in the 80s in the very competitive retail and FAILED realm, and later DIY, there is NOTHING more eye opening and revealing, but consequently more of a drastic "Let down" to see ones own creation, be it retail or DIY get brought into reality.

 

[WOLFAGRAM]

With most of my speakers I place a thick floor cushion on the floor in front of the speakers for listening sessions. There is difference however it is generally subtle. I don't do anything with the ceiling but in the future I might. If you have high ceilings or vaulted ceilings this is much less of factor.

When listening to music on my Wharfedale's, which sit on stands some 30 cm from both sides of my TV, I cover the TV screen with a thick blanket. The difference is very subtle with acoustic/organic music and a bit more pronounced with rock/metal/electronica.

 

[Maiky76]

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:

View attachment 52606​

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:

View attachment 52608​

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:

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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:

View attachment 52611

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:

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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:

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

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

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Advanced Speaker Measurements

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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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Just for completeness sake, after the review of the newer version:

Ascend CBM-170SE2 Speaker Review

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. There is a grill which I removed, making the speaker look utilitarian. Pick it up though and you realize it weighs more than...

www.audiosciencereview.com

Score no EQ: 3.8
With Sub: 6.6

Score EQ Score: 6.2
with sub: 8.5

No EQ:

WIth EQ:

EQ:

Ascend Acoustics CBM170 SE APO Score EQ 96000Hz
August062026-114645

Preamp: -2.90 dB

Filter 1: ON HPQ Fc 49.0 Hz Gain 0.00 dB Q 1.35
Filter 2: ON PK Fc 143.5 Hz Gain -2.06 dB Q 1.12
Filter 3: ON PK Fc 519.5 Hz Gain 0.94 dB Q 6.00
Filter 4: ON PK Fc 844.6 Hz Gain -1.88 dB Q 1.87
Filter 5: ON PK Fc 1771.4 Hz Gain 1.74 dB Q 1.54
Filter 6: ON PK Fc 4445.4 Hz Gain -4.68 dB Q 0.45