Hello Camplo
It goes back too designing my HT. 85db is about where I listen and I wanted a system that could hit THX peaks. My mains are active and 98dB so with a pair of them at my listening distance it was doable. I usually never listen that loud and I have plenty of headroom so it always stays clean and unstrained. If I get the urge I can chase myself out of the room. Also bass at those levels no furniture shakers needed.
Rob
I would be interested in measuring each section, (speaking on your current Synergy) solo'd, and at peak levels, like 115db/1m(THD). I share your thoughts on max excursion of a driver affecting HF of said driver. I think it is synonymous within the community actually and not trivial. The grey area being, whats perceptible
I agree, based on my readings about the average motor, and personal experience with the woofers I have, it seems to line up. How this works with a compression driver I am not sure....the excursions are so small I don't think BL falls at all, but I have never seen BL curves for a large format compression driver.
So I did some comparison with my U-Mik, vs the Iphone SPL meter app.... Focusing on the matter of peak readings. The app Lcpeak vs rew True ZPeak, It seemed to stay mostly accurate. The phone stayed consistently 2db higher than the microphone, in the loud passages and in the lower passages not sure whats going on lol. I don't think they are using the same formula to derive peak but its seems to be close enough for ball parking what I am trying to analyze.
Im not sure what do with this one, but it happened more than once, kinda strange because I nvr came across such high readings later into the movie....just longer durations with the 128db peaks....climax of the movie likely.
Factor in the 2db difference I had with my u-mik, these numbers are still high. 130db peaks? 126db peaks?
"C" weighting is -8.5dB at 16 and 16kHz, "Z" should be flat, +/- 1.5dB from 8 Hz to 20kHz.
Hand claps at 1 meter can be over 125dB peak, so an LC peak of 132.7 at close range would easily be possible.
Have you verified the iPhones internal microphone circuit and SPL meter app remains accurate at those levels?
Art
While the recent generations of iPhone mics are useful for an average 'guideline' exposure metric in hearing health - like the NIOSH app intends - they clearly state that it isn't accurate at those levels.
I've had a license for all modules of StudioSixDigital's AudioTools app for several years, and therefore several generations of phones going back to the 5S. All the microphones start clipping at around 105 dB linear SPL in the bass region.
Interestingly, the Apple Watch appears to use a different microphone design and/or filtering setup. It is fixed to only display A-weighted values. In some off-the-cuff comparative tests with calibrated isemCON & B&K mics, my Series 6 Watch was consistently within 2 dB of the professional mic's readings for dBA values, up to around 120 dBA with a 500 ms time averaging. I stopped the rough experiment there simply because I couldn't handle any more level than that, even with earplugs in. High Intensity Acoustic Testing is no joke... 146 dB linear SPL across a large area for 30 minutes is a serious task.
It's very intriguing to carry an SPL meter with you at all times, constantly logging and making charts. Looking back over the last few years highlights how quieter things were during the pandemic 'proper'.
While I would never suggest the values shown by a Watch or iPhone are credible against a professional meter, the little taps on the wrist remind me to put my plugs in when I'm working and likely have given me several more years of good hearing health as a result.
Last edited:
???
I didn't compare it to any specific system, just my entire experience to date, but my long gone biggest stereo horn system had gobs more Sd than DSL's LCR SH50s be it driver Sd or horn mouth Sd and I forget what the smaller surrounds were and the subs were dual DTS 20.
The electronics stacked on the table certainly out shined anything I've ever owned and it wasn't clear to me or the marketing? guy with me whether it all was in 'play' or not, ditto the huge prosound mixing board, but the system's 'sharpness', lack of distortion/whatever just flat stunned me, especially considering the building's construction with its bay doors open; I mean that's FOCUS! Like I've attained by horn loading 'FR' drivers, but the closest I ever came was some WHW using Altec 511 with dual 416 where the 416s were canted forward to focus at a fixed distance, so had I been as inventive as Tom to finish the folding..........
Anyway, in retrospect, in a way it reminded me of listening to an 846 Valencia in Altec's anechoic chamber, i.e. kind of eerie is the best I can explain the 'hair raising', but as you surmised it has IME to be primarily the complete summation of a properly done multiway horn because I had the rest of the requirements 'covered in spades'.
WRT 'FR' flatness, have no idea about the DSL as the tech guys were in a scramble to finish the Matterhorn and down to Tampa? for a trade show, so couldn't ask any tech Qs and the rest of the high end consumer systems were typically anything but flat, ditto my various systems because quite frankly I've found them BORING. I was raised on a wide range of unamplified live music, so for better or worse it's my standard, ergo were 'voiced' 'in situ' by young women with their more acute hearing.
Movies, prosound, 'canned' music best to be pretty flat and EQ to suit the room.
As for mastering monitors, all I really know is that the pioneer's systems were anything but flat and judging by history they worked really well.
My fault, I mean to say extremely smooth. With FIR filtering, I would imagine that a smooth FR is a realistic goal for all but those systems with too far away from the target
The midbass is the one place I question about synergies...either sd or xmax is going to be needed to make up for the tiny holes used to let in bass to the horn. There was some talk about masking of THD but Im skeptical. @mark100 - What size are your woofer ports? Using hornresp we can kinda get an idea of the excursion... 2, 2" holes keeping up with a 15" direct radiator in the 65hz-200hz sounds iffy.
Another thing @mark100 ... concerning 1/4WL, hows that work in the upper midrange/low treble??? The tweeter to the next driver in line, thats within 1/4WL???
1/4 distance at 6000hz is near 0.5" inches... thats lower than the spacing in your Syn Horn isn't it???
I hear FIR being brought up again at the mention of difficult jobs, but it's sufficient to say smooth, that can be done regardless... FIR has its uses in the right hands of course but it could also be a temptation to lawnmower EQ even those things that shouldn't be EQed.
That question is already answered if you look at the overlap of the output of drivers that Mark posted a few posts ago:
I guess you missed the fact that Mark uses a coaxial compression driver that crosses at 6K?
Plus I'm pretty sure the woofers in his Synergy don't have to run down to 63 Hz.
When I look at the synergy horn, I think ok, every where theres a hole, there will be "turbulence" in the pressure waves....Diffraction is probably a better word.
Why not try to keep as many holes on the vertical planes of the horn...cause **** the vertical right? I mean before you'd **** the horizontal. The CSA of the horn where the holes are, are adjacent to the frequency where the anomalies will over in the FR.
Why not try to keep as many holes on the vertical planes of the horn...cause **** the vertical right? I mean before you'd **** the horizontal. The CSA of the horn where the holes are, are adjacent to the frequency where the anomalies will over in the FR.
Last edited by a moderator:
I would imagine that the horn CSA where the holes are placed, are designed to take care of diffraction or avoid it, or remedies it because, the driver, in the hole is its own source of radiation? As well, the Hole CSA is designed to not beam before the upper cutoff. There is a cancellation from the reflection on the inside of the horn. No?..... this cancellation is the mechanical high pass they talk about? same with the reflection inside the hole of the woofer.
Last edited:
You raise a good point about a synergy horn providing inherently good pattern matching.I wouldn't so much lean on that, but due to the use of the same horn they have pretty good 'pattern matching'
On the other hand, that is also possible with a two-way. Also the shape of synergy horns is often guided by 'other' concerns.
I guess it can be considered to do so, down to Keele's classic formula for lowest frequency of pattern control.
(lowest pattern control freq = 1,000,000 / horn dimension in inches / horn angle in degrees.)
All the syns I've built have had held horizontal control between 200-400Hz...so yeah, no pattern matching of direct radiators needed until down to there.
No CD/horn to direct radiator pattern matching needed....yay!
What I'd really like, as many others have said too, is the cleanliness of an Ath or OS horn that's large enough to hold pattern control well below 500Hz....AND allow mounting drivers to it.
I want a SynAth horn
That said, I think it is pretty safe to "lean on" the idea of the tighter driver spacing a synergy offers being a prime factor to SQ.
Pattern matching, along with constant directivity horns, provide an overall outline of directivity imo.
Inside that outline is all the lobing, interference, phase mismatch, etc, from multiple drivers exceeding 1/4 WL spacing.
Which matters more? Overall outline? Or the muck within the outline? Who knows for sure, but surely both are important.
Oh, what do you mean by shape of synergy horns is often guided by 'other' factors...please don't be cryptic...just explain what you mean. Thx.
That project shows the one thing I dislike about my current syn10 setup. The c2c distance between the 15" coax and the sub's slot is about 32", same as for the syn10. Which gives 1/4 WL at 105Hz. I cross all my syns steep at 100Hz, but still some summation above 105Hz falls outside of 1/4WL.
Kinda ironic the only xover I have trouble with maintaining 1/4WL is the lowest one huh?
Next PPSL sub, if i ever build one, will have slot at the top !
I did a bunch of testing on this a while back, but like said, still trying to come to grips with what the measurements really mean.
Here's one example of comparing the small mids vs the CD with a 500 Hz CEA tone burst.
SPL meter is hard to read...ignore main display.
LZpeak of 127dB for small mids of left. LZpeak or 123 dB for 4594HE CD or right.
Regarding syn ports....
I use 1/8th Sd for sizing the total port area per driver. Seems to work well for 4" and 8-12".....getting ready to find out how it works for 18".
Here' a pict of work in progress, adding two 18"s to an old 75x60 proto.
It's kinda exciting realizing that two 18"s, two 12"s, four 4"s, and a CD are all about to play through rectangular window that's only 21"x16". (outer edges of 18" ports)
Solves the sub spacing problem I started off with, huh?
We'll see...it ain't over till the fat syn sings... lol
The standard arrangement... They start conical, ports iin the corners, narrow angle - usually put over one dimension, held that way until a secondary flare. These things are there for a reason.
Reading my mind. Thats why I posted the Red horned system. Looks a little more waveguidey. Why not an classic OSWG? Its still the bee's knee's.I want a SynAth horn
I'm not sure how you approach placing the holes and deciding shape n size but If I gathered right, one would just place the holes, matching the horn/waveguide CSA to the passband of the driver??? You essentially could take any Horn/Waveguide and turn it into a Syn? I could turn my tractrix horn into a Syn lol
Last edited:
Something that some "scientific people" at some other web forums, don't seem to understand...........
But anyway, that's a little offtopic.
Except for the phase there are no benefits for using FIR vs IIR when being used the "traditional" way, which seems to be implied with the brought up discussion.
The only exception here is using it as a convolution/convolver/impulse response.
But to repeat it again, just EQ'ing without knowing and understanding can lead to (very) unsatisfying results.
And in some cases even damage your system. (no, that is not being dramatic).
It's most definitely subjective pixel peeping then being really scientific about it as well.
The same goes for just only preferring 1st ordering filtering.