Ascend CBM-170SE2 Speaker Review

[AscendDF]

As I'm sure you are aware, SEAS has several stock tweeter models available with truncated faceplates, so the "custom" aspect is not really the faceplate I would presume (as is the standard sized circular faceplate of the Sierra model).


View attachment 553289

The 27TFFNC/CG did not exist when SEAS made the tweeter we are discussing, this was way back in 2004/2005. But also, please look carefully - our faceplate is quite a bit different, much smaller radius for the curved sides, altogether different dimensions.

As I previously mentioned, SEAS designed this tweeter for us to be a drop in replacement for the original CBM-170, which was a variant of the Audax TM025. Harman bought out Audax and eventually scaled down production, so we sought out a new vendor that also had the ability to make improvements to the original design. For example, the original Audax dome had a mild horn load (which I didn't like as it narrowed dispersion) and we also wanted to lower the resonant frequency, which was accomplished using a double chamber (Audax did not use a chamber behind the dome). Additionally, we sought higher power handling (the Audax was a bit fragile).

Here is a pic I found online of the original Audax tweeter we used.

You can see how the outer dimensions of our faceplate as well as the location of the mounting screws are an exact match.

I don't remember the exact details, it was a long time ago - but at some point, SEAS had told me they would release a similar version with different dimensions - that likely ended up being the 27TFFNC/CG.

I know it seems unlikely that a company like SEAS would build custom product for a company seemingly as small as Ascend, but honestly - they do it for us all the time, it is a mutually beneficial agreement. We buy in large quantities and have been working with them for so long now. They are constantly making new prototypes for us, even as I type this. Some developments end up being used, some do not. I am quite old-school in this aspect of business, I am extremely loyal to our vendors and we have a wonderful working relationship with them.

Using the below link, you can see the tweeters (and woofers) SEAS offered at the time we released this tweeter.

SEAS Standard line, line up

They did not offer even one neodymium based 27mm dome, a few 25mm domes, none had the double chambered magnet system.

 

[AscendDF]

I think hat Ascend Acoustics simply took the Seas 27TFFNC/CG tweeter, removed the honeycomb grilles, and likely made slight modifications to the design.

View attachment 553295

Stock spec

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I can see how someone can make that assumption, but please see my previous post. This tweeter did not exist when SEAS made the tweeter for us.

 

[AscendDF]

Danny Richie would have those sand core resistors and iron core inductors in the bin straight away!

And ruin all the hard work.

The only actual "issue" with wire wound resistors is that they generate a very small amount of inductance. The "sand" casing isn't actually sand, it is silica, and it is used to dissipate heat. ALL resistors work this way, they trade voltage for heat, and that heat must be dealt with. That silica surrounds the outside and inside of the coil, acting as a heat sink. Silica is inert and is an excellent electrical insulator, it has absolutely no effect on the actual electrical signal. Imagine if silica actually did have an effect on an electrical signal? Nothing would work, our cars, phones, computers - nothing - and we are talking about microvolts here with massive miniaturization (computer chips), let alone something as simple as an audio signal.

That inductance created - which is FAR lower than the inductance of any speaker's voice coil, can slightly roll off some high frequencies, but this is typically in the MHz range, far above what a human can hear and even what a speaker or amplifier can reproduce. Additionally, using what is known as bifilar winding, these same sand cast resistors can present a purely resistive load. We often use a bifilar wound cast resistor in series with the tweeter, it often uses an "NRX" designation.

 

[ShadowBoxer]

The 27TFFNC/CG did not exist when SEAS made the tweeter we are discussing,

I'm a bit confused. So, the V2 redesign uses the same physical tweeter dimensions of the V1 legacy tweeter from 20 years ago? Is that correct?

 

[AscendDF]

I'm a bit confused. So, the V2 redesign uses the same physical tweeter dimensions of the V1 legacy tweeter from 20 years ago? Is that correct?

The CBM-170SE2 is now the 3rd variant. The original CBM-170 (Audax tweeter and Audax woofer), we then released the CBM-170SE ~21 years ago (custom SEAS tweeter - the one being discussed + fully custom woofer) and now the CBM-170SE2 for which we redesigned the woofer, the cabinet, crossover, and port.

The same SEAS tweeter from the CBM-170SE is still being used (there was no reason to change it)

If you would like to read more, it is all in our forum here:

https://forum.ascendacoustics.com/home/forum/ascend-acoustics-discussions/loudspeakers-subwoofers-accessories-electronics/124657-a-legend-reborn

Also, somewhere in our forum from at least 21 years ago, there is a detailed discussion about this then new tweeter. Seems like almost yesterday.

 

[daniboun]

I can see how someone can make that assumption, but please see my previous post. This tweeter did not exist when SEAS made the tweeter for us.

My bad. Anyway you made an excellent job.
Thanks for those explanations

 

[Matt_Holland]

The only actual "issue" with wire wound resistors is that they generate a very small amount of inductance. The "sand" casing isn't actually sand, it is silica, and it is used to dissipate heat. ALL resistors work this way, they trade voltage for heat, and that heat must be dealt with. That silica surrounds the outside and inside of the coil, acting as a heat sink. Silica is inert and is an excellent electrical insulator, it has absolutely no effect on the actual electrical signal. Imagine if silica actually did have an effect on an electrical signal? Nothing would work, our cars, phones, computers - nothing - and we are talking about microvolts here with massive miniaturization (computer chips), let alone something as simple as an audio signal.

That inductance created - which is FAR lower than the inductance of any speaker's voice coil, can slightly roll off some high frequencies, but this is typically in the MHz range, far above what a human can hear and even what a speaker or amplifier can reproduce. Additionally, using what is known as bifilar winding, these same sand cast resistors can present a purely resistive load. We often use a bifilar wound cast resistor in series with the tweeter, it often uses an "NRX" designation.

Very informative, thanks! Isn’t it just mad what lies people spout in order to sell their snake oil.

I put Ascend in a similar category as Buchardt Audio. You both have a complete understanding your customers and appeal to both subjecivists and objectivists with products that are designed using the best engineering principles and measurements, but with final tuning done by ear.

 

[John.D]

There has never been a specific center channel speaker per se for the CBM-170.

I thought signature series center is essentially center to be used with signature series bookshelf speakers.

​

 

[John.D]

Which center are you referring to? Our 340SE2 center is the ideal matching center to the 170SE2, also many customers are ordering a single 170SE2 for use as the center.

CMT-340SE2 CENTER

Uncompromising Performance, Our Best Value! New Klippel NFS optimized version! Using high resolution 360-degree measurements generated by our Klippel NFS, we have completely redesigned our highly revered CMT-340SE resulting in MAJOR improvements in every performance category. We have also given...

www.ascendacoustics.com

Vertical dispersion doesn’t look idea in my limited knowledge for CBM-170SE2.

PE. Which one should be accurate matched response when using it as center lying on side - vertical or horizontal?

 

[DanTheMan]

Vertical dispersion doesn’t look idea in my limited knowledge for CBM-170SE2.

PE. Which one should be accurate matched response when using it as center lying on side - vertical or horizontal?

I'd personally argue that the horizontal response is more important for the center channel, but the vertical response is actually better than possible any speaker I've measured. A vertical arrangement should be best.

 

[Mark609]

I don't want very little if any vertical dispersion in a center. Will take plenty of horizontal though.

 

[wndbrkr]

What would be an ideal subwoofer to pair with the Ascend CBM-170SE2?

 

[Power Pop 23]

What would be an ideal subwoofer to pair with the Ascend CBM-170SE2?

Welcome to ASR,

It may depend on the size of your listening space and how loud and low you want to go

One option (in the USA) is the $339 RSL Speedwoofer 10e

Landing Page - 10E

Fast, powerful, and affordable. The Speedwoofer 10E delivers deep, controlled bass with legendary RSL performance.

rslspeakers.com

 

[daniboun]

What would be an ideal subwoofer to pair with the Ascend CBM-170SE2?

Checkout
SVS SB 1000pro is a nice option

Subwoofer Comparison (by @sweetchaos)

bit.ly

 

[John.D]

Might be useful to try keeping close to wall when used without sub but still 60-65Hz isn't going to be enough.

Why did you say 60-65 hz?

 

[kyuu]

Why did you say 60-65 hz?

View attachment 555508

From the actual measurements. I'm not sure how meaningful it is to state a "typical" in-room response with a bass reflex design.

 

[John.D]

From the actual measurements. I'm not sure how meaningful it is to state a "typical" in-room response with a bass reflex design.

I would, in fact, thought opposite. I thought in-room is more important and practical than anechoic.
Thanks

 

[John.D]

CMB170SE tweeter has no protection, like others have some sort of plastic, fiber or metal mesh or something covering.
Is there any such aftermarket product that could be used for some protection?

 

[ShadowBoxer]

The same SEAS tweeter from the CBM-170SE is still being used (there was no reason to change it)

So, when Amir stated in his V1 review that the treble was way too hot that was due to.....?

 

[YouDontHaveEnoughBass]

Crossover design