OP
- Thread Starter
- #21
Added Danny's original before and after measurement in his V1 video to the review.
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GR Research Speaker Upgrade Review (Sierra-2EX V2)
- Thread starter amirm
- Start date
diddley
Addicted to Fun and Learning
I feel sorry for Dave to see mans work so being raped by a charlatan, a nobody, a poser.
He definitely deserves better. They make a great product by all accounts and I almost bought their ELX towers. I'm sure I'd be just as happy with those as my BMR Towers.
OP
- Thread Starter
- #24
Not correct. Gating by definition, reduces the number of samples in time domain. Heisenberg's uncertainty principle kicks in here, mandating that reduced number of samples results in lower resolution in frequency domain. That is why his graph starts at 200 Hz as his software software "knows" this. But resolution above 200 Hz is also compromised which some people don't realize and is not indicated on the graph.
As to Klippel, it does indeed rely on gating for high frequency region. But then uses the dual scan phase separation to filter out the reflections below that limit, fully preserving the resolution from start to finish. Danny could do the same by performing ground plane measurements and stitching the two together but he is not doing that.
For an example of someone who knows this, note this remark in many of James Larson's measurements:
"The Philharmonic BMR HT Tower speakers were measured in free-air at a height of 4 feet at a 2-meter distance from the microphone, with the microphone raised to an 8’ elevation that was level with and aimed at the tweeter center. The measurements were gated at 8 milliseconds. In this time window, some resolution is lost below 400 Hz and accuracy is completely lost below 200 Hz. "
tineared
Addicted to Fun and Learning
Are you planning on making a video for YouTube demonstrating this GR modification? The responses in the comment section would likely be, as they say, priceless ...
Indeed. Please make one Amir, if only for the laughs...
Keith_W
Master Contributor
Well, let's look at what Danny thinks he has done vs. what he has actually done.
Danny's measurement: his modification boosts the low midrange between 200Hz - 500Hz by about 2dB. Also restores the high treble >10kHz to flatness. This comes at the expense of noticeably more lumpy treble frequencies, notable a dip at 3kHz, which we can see in both measurements.
Amir's measurement: very slight low midrange boost in the same region I highlighted, about 0.5-1dB at most. Slight peak in high treble > 15kHz.
After looking at this, we observe that the 3kHz dip and the treble boost >15kHz can be seen in both measurements. This can potentially be blamed on faulty microphone / improper calibration / improper measurement technique.
But what is curious is why Danny measures a low midrange boost between 200-500Hz, and Amir doesn't. The difference between Danny's "before and after" can not be explained away with an improper cal file or faulty mic - if he used the same mic, the same fault would be observed. What exactly is in that bag of mods that he sent you, and does he state what the intention of those mods are for? Is there anything in that bag that might produce a shelf?
Danny's measurement: his modification boosts the low midrange between 200Hz - 500Hz by about 2dB. Also restores the high treble >10kHz to flatness. This comes at the expense of noticeably more lumpy treble frequencies, notable a dip at 3kHz, which we can see in both measurements.
Amir's measurement: very slight low midrange boost in the same region I highlighted, about 0.5-1dB at most. Slight peak in high treble > 15kHz.
After looking at this, we observe that the 3kHz dip and the treble boost >15kHz can be seen in both measurements. This can potentially be blamed on faulty microphone / improper calibration / improper measurement technique.
But what is curious is why Danny measures a low midrange boost between 200-500Hz, and Amir doesn't. The difference between Danny's "before and after" can not be explained away with an improper cal file or faulty mic - if he used the same mic, the same fault would be observed. What exactly is in that bag of mods that he sent you, and does he state what the intention of those mods are for? Is there anything in that bag that might produce a shelf?
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I've been telling the guy that his test gear is grossly inadequate for years -- he uses some elderly Clio system from Italy which is to a Klippel NFS what a rusty Fiat 500 is to a Mercedes-Benz S-Class.
I guess reproducibility could also be an issue here. There are a lot of variables with a spread in component values. If he 'fixes' one sample, its questionable it will work the same in other instances of the same mod.
DatSpeakerTho
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Its possibly just the circuits Danny is using are reacting with the drivers impedance. One can quite easily end up with bumps in this range, if theyre not implementing a good filter. I sometimes apply a parallel notch to fix these low range bumps if no other option is available.
Why in the world would anyone want to modify a Sierra 2EX v2—a phenomenally measuring speaker? Why did Danny accept this assignment?
sam_adams
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Gating and smoothing of measurements are the "Shallow Hal" effect for measurements far outweighing the "Beer Googles" effect.
The Clio he uses is entirely capable of decent measurement results. It's everything else that is the problem.
That's an excellent question.
Oh my, Danny is getting ripped here. Seems like he stuck his nose into something that did not need fixing. I have the Ascend Acoustics Sierra-2EX V2 and they are excellent, I suspect I will never part with them as well as my Philharmonic BMR's. Those two speakers have one thing in common - the RAAL. To my ears it produces wonderful music, with its limits of having narrow vertical dispersion.
OP
- Thread Starter
- #37
Of course he didn't send me anything. Someone bought it from him, or was the original person who sent him the speaker, and Dave from Ascend built the crossover and installed it.
Someone voted "fine". 
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I could not help but notice the absence of this disclaimer from the text of this review.
No loudspeaker was harmed in the creation of this review.
When the dust eventually (sorta) settles, I hope the rescue of a large whale in the North Sea inspires an ASR member to remove this modification and restore this Ascend Sierra-2EX V2 'sample' with OEM parts.
No loudspeaker was harmed in the creation of this review.
When the dust eventually (sorta) settles, I hope the rescue of a large whale in the North Sea inspires an ASR member to remove this modification and restore this Ascend Sierra-2EX V2 'sample' with OEM parts.
For the money of the "mod" you can buy speakers that most here would rate "fine"Someone voted "fine".
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