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Old 28th December 2011, 02:19 PM   #1201
Xoc1 is offline Xoc1  United Kingdom
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Quote:
Originally Posted by weltersys View Post
Xoc1’s TH18-2 has the same physical dimensions as the DSL TH-115 or TH-118, and similar frequency response as the TH-118, which uses the BC18SW115-4.

The DSL TH-118 is rated at about 105 dB one watt one meter (spec sheet uses 28.3 volt at 10 meters).

My slightly larger volume Keystone BC18SW115-4 loaded tapped horn actually measures about 98 dB sensitivity in the upper range (same as a JBL-SRX 728, a slightly larger 2x18"), about the same as Xoc1’s TH18-2 Hornresp sims.

I have communicated about the disparity with Tom Danley, although he agreed that the disparity sounds too large, he stands by the spec sheet figures. He did share the actual plans of the TH-115 with me, Xoc1’s TH18-2 are nearly identical other than one small detail that Tom does not believe would make much difference in sensitivity.

Josh Ricci has tested a DSL DTS-10, his test results show a much lesser sensitivity than Danley’s spec sheet, very much in line with the disparity between Xoc1’s TH18-2 or my Keystone compared to the DSL TH-118.

My tests showed the TH increased the sensitivity of the BC18SW115-4 by 6 dB over a slightly smaller BR cabinet with the same low corner.

Six dB is a big deal, another 6 or 7dB on top of that with the same FR and cabinet volume (and fold pattern) is IMHO, impossible.

Art Welter
Looking closely at the Danley TH118 Spec Sheet
http://www.danleysoundlabs.com/pdf/T...ec%20sheet.pdf
It does say 4 ohm 28.3V @ 10 metres.
Is this not equivalent to 40V @ 10 metres or 4V @ 1 metre for an 8 Ohm driver
Regards
Martin (Xoc1)
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File Type: jpg TH18 BC18SW115-8.jpg (116.5 KB, 425 views)
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Old 28th December 2011, 02:46 PM   #1202
tb46 is offline tb46  United States
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Hi Xoc1,

That's correct, but it only accounts for 3dB.

Regards,
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Old 28th December 2011, 03:03 PM   #1203
PASC is offline PASC  Brazil
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may be actual numbers are

+- 98dBs 1W/1M
Plus 1800W = 32.6 dBs
Results 130.6 dBs
Account power compression of 2.2dBs at AES Pe
Final result real world = 128.40 dBs at best

Difference = marketing ????????
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Old 28th December 2011, 03:21 PM   #1204
PASC is offline PASC  Brazil
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Should the difference in real world account for the DSP applied to the test of power aes...

See the blue curve of AES standart (from 50 to 500Hz?) bellow link picture;

-+ -3dBs at 50Hz and +- -6dBs at 40Hz, +- -10dBs around 30Hz

Speaker power handling < Pro-Audio References
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Old 28th December 2011, 04:59 PM   #1205
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by Xoc1 View Post
Looking closely at the Danley TH118 Spec Sheet
http://www.danleysoundlabs.com/pdf/T...ec%20sheet.pdf
It does say 4 ohm 28.3V @ 10 metres. Is this not equivalent to 40V @ 10 metres or 4V @ 1 metre for an 8 Ohm driver. Regards Martin (Xoc1)
Quote:
Originally Posted by tb46 View Post
Hi Xoc1, That's correct, but it only accounts for 3dB. Regards,
Hi Martin and Oliver,
In Danley's sheet, they seem to use the reference of 2,83V @ 1m in a ˝ Space environment for 108dB avarege and 114dB at 138Hz peak. In that case Martin's Xoc1 TH18-2 does perform even 3dB higher in average.

Danley's SPL response shows that the hardware inside cannot be similar to Martin's Xoc1-TH18. Tom seems to trade 3dB (average) for extra extension down low. Also the peak at 138Hz of Danley’s TH118 is evidence of lower resonances. If you look to the impedance plot it becomes much clearer. While the Cox1-TH18 has his impedance peaks at 45Hz and 104Hz, Danley’s TH118 impedance peaks are at 43Hz and 95Hz.

Looks to me Danley’s TH118 has an 1/3WL of 33Hz and a 1/4WL of 23Hz. That is also a logical explanation for the 3dB less average sensitivity of Danley’s cab in favour for 5Hz extension. That sounds very realistic to me.

Last edited by Djim; 28th December 2011 at 05:16 PM.
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Old 28th December 2011, 05:18 PM   #1206
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Quote:
Originally Posted by Djim View Post
Hi Martin and Oliver,
In Danley's sheet, they seem to use the reference of 2,83V @ 1m in a ˝ Space environment for 108dB avarege and 114dB at 138Hz peak. In that case Martin's Xoc1 TH18-2 does perform even 3dB higher in average and 1dB higher in peak.

Danley's SPL response shows that the hardware inside cannot be similar to Martin's Xoc1-TH18. Tom seems to trade 3dB (average) for extra extension down low. Also the peak at 138Hz of Danley’s TH118 is evidence of lower resonances. If you look to the impedance plot it becomes much clearer. While the Cox1-TH18 has his impedance peaks at 45Hz and 104Hz, Danley’s TH118 impedance peaks are at 43Hz and 95Hz.

Looks to me Danley’s TH118 has an 1/3WL of 33Hz and a 1/4WL of 23Hz. That is also a logical explanation for the 3dB less average sensitivity of Danley’s cab in favour for 5Hz extension. That sounds very realistic to me.
In post 1188 your graph says 1w 1m sensitivity for the Xoc1 TH18-2 with the B&C18SW115 is 98.7 dB.

The adjusted average sensitivity for the DSL TH-118 is 105 dB.(108 -3 dB ).

Why do you say that Xoc1 TH18-2 is 3dB higher in average and 1dB higher in peak?

Art
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Old 28th December 2011, 05:26 PM   #1207
Djim is offline Djim  Netherlands
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Quote:
Originally Posted by weltersys View Post
In post 1188 your graph says 1w 1m sensitivity for the Xoc1 TH18-2 with the B&C18SW115 is 98.7 dB.
The adjusted average sensitivity for the DSL TH-118 is 105 dB.(108 -3 dB ).
Why do you say that Xoc1 TH18-2 is 3dB higher in average and 1dB higher in peak?
Art
I use 1w/1m in 2 Pi spaces as a reference for comparing all cabs in my table, which is the original AES standard to prevent confusing from different impedances. Danley measures with 2,83V with a 4 Ohm driver in 1/2 Space as his sheets explains. But if you want to be more precise it will probably end in a difference of 2,6 to 2,8dB, have to do some accurate recalculating before putting Danley's cab in the table.

Last edited by Djim; 28th December 2011 at 05:31 PM.
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Old 28th December 2011, 05:45 PM   #1208
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2pi and halfspace is the same!..?
While we are on it; have anyone noticed the difference in the impedancegraphs on TH-115 and TH-118?
Isnt it the same enclosure?

Dag
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Old 28th December 2011, 06:42 PM   #1209
djk is offline djk
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No, the TH-118 has a longer air path. From the impedance graph it looks like the 118 is tuned around 28hz, and the 115 around 37hz or so.
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Old 28th December 2011, 07:30 PM   #1210
Djim is offline Djim  Netherlands
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Problem is we don't have an impedance plot of the Xoc1-TH18 (other then a HornResp model) to compare with the Danley's TH118 measurements for exact conclusions, but I do agree my 1/4WL assumption is a little too low.

However, I did use Danley's SPL chart and recalculate the plot from SG3225 from the Cox1-TH18 loaded with a 8Ohm B&C 18NW100. I think we can assume SG3225's equipment isn't as precise but it does give a general idea. The less roll off in the end in favour of the Cox1 is because SG3225's measurements were done at 2 meters if I remember correct (or filter settings?). To me it looks like Danley has made a mistake in his conversion calculation.

Danley's TH118 is in red and Xoc1-TH18-2 is in blue.
Click the image to open in full size.

Last edited by Djim; 28th December 2011 at 07:56 PM.
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