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Keystone Sub Using 18, 15, & 12 Inch Speakers
Keystone Sub Using 18, 15, & 12 Inch Speakers
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Old 9th May 2018, 09:34 PM   #1201
Brian Steele is offline Brian Steele  Grenada
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Originally Posted by weltersys View Post
5) There are many that complain about resonant behavior, but a 1/4 wave resonator cabinet won't work without it.
But you can push those unwanted resonances way out of the cabinet's intended passband so their audible impact is noticeably less, hence my interest in offset slot-loaded tapered TLs. Efficiency is a bit lower than a THs, but box size requirements are also lower, and out of band resonances can be pushed an octave above typical cabinet passband (~100 Hz) and they are also lower in level compared to the passband. Terminating the TL with a slot results in an Fb that's lower than a vented box of the same net volume (and the extra internal panels double as bracing), and the use of a slot instead of a full taper allows some flexibility in locating the offset to obtain the best results when the TL is folded up into a box.

An alternative approach is to design and build the TH using the process I outlined in this thread: Ooh looky - a TH that does from ~42Hz-500Hz +/-3dB

It does result in a slightly larger box though. I'm considering a redesign of my POC3 build to incorporate the larger S1-S2 volume to see if the results to match the sims.
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Old 10th May 2018, 04:35 PM   #1202
treukauf is offline treukauf
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Thanks everyone for the input. Brian, I read through your thread, and thats interesting. I am trying to learn REW now to better evaluate and tune my behringer nu/dsp amps. Going to try to test and review all of my subs this summer.
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Old 24th June 2018, 01:17 AM   #1203
radulescu is offline radulescu  Romania
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Weltersys, it seems that all your discussions about the sensitivity graph on Danley's TH118 being 3 dB higher than it should, made them measure it again and it seems now that they have changed it. Cheers
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Old 24th June 2018, 02:10 AM   #1204
Brian Steele is offline Brian Steele  Grenada
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Do you have a link to the new measurements?
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Old 24th June 2018, 11:16 AM   #1205
Osse is offline Osse  Sweden
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TH118 | Danley Sounds Labs | Danley Sound Labs, Inc.

Took some time for them
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Old 24th June 2018, 04:34 PM   #1206
weltersys is offline weltersys  United States
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Originally Posted by radulescu View Post
Weltersys, it seems that all your discussions about the sensitivity graph on Danley's TH118 being 3 dB higher than it should, made them measure it again and it seems now that they have changed it. Cheers
Funny, the 2.83V/4 ohm "sensitivity" is 105 in the Architect/Engineer Specs, while it still is 108 in the "key features" area of the spec sheet.
Same mistake in the larger TH118XL specs. The TH118XL has about +3dB more output at 30Hz than the current TH118 (but less than the old TH118 measurement...)

Sometime around May 2018 they had updated the TH118 impedance chart (the 18Sound driver in the original TH118 had an impedance minima of 3 ohms)without changing the frequency response chart. Oddly, the lower impedance minima somehow went up from around 28 to 35 Hz.
No impedance charts were included in the current TH118 or TH118XL spec sheets, but the frequency response has been re-measured, probably when they noticed the previous TH118 appeared more "sensitive" than the larger TH118XL.
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Old 24th June 2018, 04:48 PM   #1207
Brian Steele is offline Brian Steele  Grenada
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Originally Posted by weltersys View Post
Funny, the 2.83V/4 ohm "sensitivity" is 105 in the Architect/Engineer Specs, while it still is 108 in the "key features" area of the spec sheet.
The FR graph for the TH118 seems to show it hitting around 108dB/2.83V/1M at just over 100 Hz. Between 50 to 100 Hz, it's around 105dB/2.83V/1M, and slopes off below that.


Quote:
Originally Posted by weltersys View Post
Sometime around May 2018 they had updated the TH118 impedance chart (the 18Sound driver in the original TH118 had an impedance minima of 3 ohms)without changing the frequency response chart. Oddly, the lower impedance minima somehow went up from around 28 to 35 Hz.
Now THAT I'm more interested in. I remember having a lot of discussion with JAG over that, him insisting that the minor changes in the TH118 compared to the TH115 of the same dimensions is what caused the lowest resonance frequency to drop to 28 Hz, and me responding that there was no way those minor changes could have made such a significant difference in the resonance point.

https://www.danleysoundlabs.com/danl...ecs-V2.0-1.pdf
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Old 24th June 2018, 05:25 PM   #1208
weltersys is offline weltersys  United States
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Quote:
Originally Posted by Brian Steele View Post
I remember having a lot of discussion with JAG over that, him insisting that the minor changes in the TH118 compared to the TH115 of the same dimensions is what caused the lowest resonance frequency to drop to 28 Hz, and me responding that there was no way those minor changes could have made such a significant difference in the resonance point.
The LF impedance response of the BC18SW115-4 TH-118 appears to have changed back to being more similar to the TH-115 in the more recent (bottom chart) measurement, compared to the older 18 Sound loaded TH-118 (center chart).
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File Type: png TH115, TH118,TH118Recent.png (255.5 KB, 95 views)
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Old 24th June 2018, 06:05 PM   #1209
Brian Steele is offline Brian Steele  Grenada
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Yup, that's exactly what I'd expect the impedance curve of the TH118 to look like.

Interestingly, the spec sheet indicates that the TH118 goes down to 29 Hz, which is below the lowest impedance mininum...
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Old 24th June 2018, 06:13 PM   #1210
Moderation Team is offline Moderation Team
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Keystone Sub Using 18, 15, & 12 Inch Speakers
@Art & Brian - please stop quoting the post directly above yours when replying. See diyAudio Rules
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