It strongly resembles the look and performance of the Directiva without the passive woofer. Coincidence?
-
WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!
Ascend Sierra-1 V2 Speaker Review
- Thread starter amirm
- Start date
Your assumption on the design goal for this speaker is wrong.
As discussed in detail on our forum with its release, the goal of this speaker was as even and as neutral a sound power response as we could achieve. As you know, sound power represents the total radiation of the speaker and, in my professional opinion, best represents a speaker’s overall neutrality.
It is all right here in our forum from many months ago. See my 2nd post:
Sierra-1V2
To accomplish this, it meant precisely matching the directivity of the woofer and tweeter at crossover. Doing so without a waveguide on the tweeter is an extremely difficult task, but it is possible as these measurements clearly indicate. It was also our goal to offer wider horizontal dispersion, something a waveguide limits.
This meant sampling dozens and dozens of tweeters and it just so happened that a new tweeter from SEAS offered better directivity than the highly regarded 27TBCD, more commonly known as the DXT, which incorporates a highly specialized deep waveguide. It was my understanding from my discussions with SEAS that this new tweeter will eventually replace the DXT. (note the similar model designations). The Titan tweeter has much wider dispersion, lower distortion, and a more linear frequency response. Feel free to contact SEAS directly to discuss this. Exactly how they accomplished this directivity with a “flat” waveguide is a combination of many factors, but indeed - they accomplished it and the proof is right there. I was quite shocked as well, and I also publicly mentioned this with the release of our LX.
Let’s compare the sound power response and ERDI of the S1V2 with the Revel M105, which takes full advantage of a waveguide. Which sound power response is the more linear in the crossover region? Which ERDI has less directivity error?
You mention tinkering to achieve the textbook PIR. How exactly? I for one would like to know how to do that. Amir posted the acoustic close mic response curves of both the woofer and tweeter, they look clean and without manipulation. The depression in the woofer starting at about 500Hz -1.7kHz is by design and is partly baffle step compensation as well as to compensate for a pesky peak in the woofer’s response that you can see in the original Sierra-1 with 3rd party measurements from the NRC:
https://www.soundstagenetwork.com/measurements/speakers/ascend_sierra1/frequency_on1530.gif
The Sierra-1V2 woofer is different than the original, but uses the same cone and surround, thus that same peak needed to be dealt with for the new version of the Sierra-1.
We managed to achieve our design goals for the sound power response by first selecting a tweeter that had the directivity we needed. And from that, literally taking 100’s of NFS scans combined with some advanced modelling we developed to determine the precise crossover point and high pass and low pass filter slopes needed to achieve this. (it helps having family with PHD’s in physics) That stated, we have only been able to accomplish this using this specific dome tweeter, which is why we used it in our LX and now with the S1V2 as well as our new towers and horizon.
You can see in the measurements of our NFS optimized 340SE2 that we could not achieve such a linear sound power response which uses a different SEAS tweeter. Believe me, if I could figure out a way to tinker with frequency response to match directivity between a woofer and tweeter, I would have done so. The only control a crossover has over directivity is crossover point and the filter slopes. Tinkering with response amplitude does not affect directivity.
The textbook PIR was not and was never the goal, it is the direct result of an incredible amount of R&D to get a textbook sound power response, which translates to ideal overall neutrality. For me personally, this dates all the way back to working with an ex-Harman engineer from about 30 years ago, something I also shared publicly. I wish I could remember his name though… If you are reading this and you remember me (I think you would, you introduced me to X-OPT crossover software at M&K) – pls send me an email to say hello.
Anyway, it is late, and I am rambling, but I do hope this makes some sense.
Linards
Member
ZolaIII
Major Contributor
- Joined
- Jul 28, 2019
- Messages
- 4,195
- Likes
- 2,475
Really hard to complain but here it goes. Wish they removed woofer resonance with crossover firstly by high pass filter @ 38 Hz and attending what remains of it around 5.5 KHz and I know it would increase bill of material but I think they had a headroom for the price. They actually did quite good jub and tweeter slope complement and fill woofer good under crossover point and all in all it's remarkable capable for it's size and on level of one size bigger one's with 6.5~7" woofer. Ideal crossover for sub's is still 110 Hz (as usual for one size bigger one's).
@amirm correct "I started with Band 2, filling that small bass dip" as you mean high mids.
After seeing a Tooles active design from decade ago and with room correction not really impressed but woted great anyway and in some aspects it is.
@amirm correct "I started with Band 2, filling that small bass dip" as you mean high mids.
After seeing a Tooles active design from decade ago and with room correction not really impressed but woted great anyway and in some aspects it is.
Our version of this tweeter (slightly different than the off the shelf version) has the breakup mode at 27kHz, which is exceptionally high for a "metal dome" tweeter. You can see this in the fundamental in Amir's distortion measurements. SEAS accomplished this by using AlMg alloy for the dome (a combination of aluminum and magnesium) I have only seen higher break-up modes in a "metal" dome with pure Be domes. In my many decades in this industry, this was the first metal dome tweeter that was not pure Be (Beryllium) that did not cause me any fatigue. It is detailed yet smooth and non-fatiguing. This characteristic was very important to me.
- Joined
- Jan 15, 2020
- Messages
- 6,903
- Likes
- 16,917
Thanks, nice to see that you subjectively prefer having the resonance further up.
If it was at 21kHz people here would be saying it is inaudible.
You can see KEF R3 Meta has it over 30kHz
KEF R3 Meta Loudspeaker Lab Report
Lab Report No 'fantasy specifications' here as the most compact of KEF's R Meta series delivers exactly what it says on the tin (ok, website). The 3.2ohm minimum/4ohm nominal impedance rating is met in practice with 3.17ohm at 142Hz although the load is
www.hifinews.com
The overall THD measurements are quite good for a speaker with a woofer of this size and having deep bass extension. Remember, that 96dB SPL at 1 meter is anechoic. In a room and with 2 speakers, that volume level will be in the 100+ dB range (depending on listening distance) and is far louder than most people would ever listen at.
Compare S1V2 THD with Revel M105 distortion:
you can see they are very similar.
Still, if you are looking for extremely low woofer distortion in the bass ranges, that is exactly what our LX gets you (combined with deeper bass, higher power handling and as many have mentioned, a lot of "slam") I am making it a priority to post some comparisons backed with measurements between these 2 speakers on our forum this weekend. It has simply become too much work for us to keep answering emails with the same questions, so I will cover this in detail in our forum as soon as I am able.
- Joined
- Jan 15, 2020
- Messages
- 6,903
- Likes
- 16,917
I would say there is no single truth there, the more the direct sound dominates at the listening position (due to smaller listening distance and/or higher absorption or larger rooms) the more it is important to get that (or the listening window) flat, the further we get out of it the more smooth sound power becomes important, that's why I asked Amir at what listening distance he did his audition but unfortunately he didn't reply yet.
I agree though that for usual home listening setups the listening distance is often quite high and there putting importance to the sound power is important, this was also the reason I also didn't like the treble of the Wharfedale Diamond 12.1 in my room.
Ideally of course someone wants loudspeakers that combine both a flat direct sound and smooth directivity/sound power, to quote Toole:
Almost 50 years of double-blind listening tests have shown persuasively that listeners like loudspeakers with flat, smooth, anechoic on-axis and listening-window frequency responses. Those with smoothly changing or relatively constant directivity do best.
totti1965
Active Member
Hey Martin, can you please tell me what NFB means? FB = Feedback? But the „N“?
Congrats to Dave the designer of the speaker, well done!
@amirm , you say that even deep bass was reproduced exceptionally well, which initially I was surprised about due to the anechoic response showing it rolling off early, but I suppose room reinforcement means that you'd get maybe around flat down to around 40Hz or just above, is that your thinking on it? That's still not particularly low bass, I'd think more like 30Hz in room is deep bass. It's a small speaker so we can't expect deep bass from it anyway.
@amirm , you say that even deep bass was reproduced exceptionally well, which initially I was surprised about due to the anechoic response showing it rolling off early, but I suppose room reinforcement means that you'd get maybe around flat down to around 40Hz or just above, is that your thinking on it? That's still not particularly low bass, I'd think more like 30Hz in room is deep bass. It's a small speaker so we can't expect deep bass from it anyway.
totti1965
Active Member
They measures pretty much the same.
SIERRA-1 V2 PAIR
Our World-Renowned Reference Monitor, Now Even Better! "Innovation, performance, intensive quality controls and environmental-friendliness all precisely balanced in a truly unique loudspeaker." Our new Sierra-1 V2 is a complete reimagining of our true classic, the Sierra-1. It fully represents...ascendacoustics.com
I love how they look like ordinary 2 way speakers but measure with smooth(ish) horizontal directivity in the crossover region like something with waveguides. Wide dispersion though. Fortunately I prefer wide dispersion. Anyone know how the ribbon version measures? Their towers are probably sweet as well.
A collection of loudspeakers measurements
www.spinorama.org
The best Ascend Audio preference rating so far -according to Spinorama.org- is the ELX ribbon tower and the Sierra LX. Best passive Speaker after parametric equalization compared with all 1100 speakers wich are measured is the ELX ribbon tower! Closely followed by the Epos ES 14 N of Karl-Heinz Fink, who uses also the Klippel NFS. But look at the active speakers also!
I can understand this logic, but using a passive high pass filter in a crossover to remove deep bass is a design no-no. Not only would this create far more problems than it would solve, it would require a MASSIVE capacitor in series with the woofer. We are talking about a 100V MPP capacitor with a value of over 500 uF. I don't think I have ever seen an audio grade metal film capacitor of this high of a value. A 100 uF MPP audio grade cap is nearly the size of a soda can, imagine 5 of those? This alone would cost us about $200 and use up the majority of the internal cabinet volume while also creating a host of other problems.
But I am curious, what woofer resonance do you mention at 38Hz? Are you referring to the near field woofer response in Amir's measurement? That "bump" which peaks at 38Hz is not a resonance, and is not actually a bump. It looks like a bump because of the dip you see at ~50Hz. The dip in the woofer response is the result of the port tune (~50Hz). This is the point where the port is most active fully limiting the response from the woofer, it is by design, it is how all ported speakers function. Below the port tune, the woofer becomes unloaded, and yes - ideally, it would be best to limit woofer excursion below port tune. But this can not be done passively (as I mentioned above). It should and can only be done actively using bass management.
Wow, that's good! Serious dedication!
AudioSceptic
Major Contributor
That is excellent. I just wonder if it was a better deal overall than selling your V1 and buying new V2.
If you consider they are both 2-way speakers designed using a Klippel, not a huge surprise. If Directiva r1 had the resources of Ascend, might have even used the same Seas tweeter.
Ascend gets good performance from its smaller woofer, but without the speaker being much more expensive, is not in the same league as the Purifi 6.5 woofer. Would be more interesting to compare to the Sierra LX.As @AscendDF alludes, it is a testimony to engineering prowess to accomplish good directivity without the use of a waveguide (and/or fancy cabinet faceting). In any case, some very impressive speakers.
beagleman
Major Contributor
Also, at least in my opinion, I find distortion levels in the mid/deep bass regions, to be far less audible than an equal distortion number in the midrange area.
It simply is not nearly as "Audible", although it makes most smaller bookshelf speakers appear bad measurement wise.
But is also testimony of how good this speaker is for the money, albeit there are things that the $3250 one can do that the Ascend can't do.
Last edited:
- Joined
- Mar 29, 2021
- Messages
- 2,409
- Likes
- 4,165
Similar threads
