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Old 3rd March 2012, 04:13 PM   #21
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Quote:
Originally Posted by David_Web View Post
This type of info should be in every review about drivers.
Have you ever experienced a "noisy" B&C driver?
Like turbulence or "farting" sound from the cooling?

The two RCF LF15G401 I had where very noisy and made a farting sound that was obnoxious at best. Worked ok though for a TH flown 5m in the air.
I only have a pair of the BC18SW115-4, they make almost no cooling port noise at full power at Xmax.

The Lab 12 makes enough "swishing" noise that I would not want to have the cooling port exposed for a home sub, but the noise is not so bad as to be noticeable on a PA application.

Sounds like the RCF LF15G401is a lot worse than that.
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Old 5th July 2012, 06:28 PM   #22
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Quote:
Originally Posted by David_Web View Post
B&C is one of the few that measures Xmax as 10% THD (as specified by AES2-1984 (r2003) for T/S parameters).
B&C SPEAKERS
Which is unlike most that uses Xmax = [(winding depth - magnetic gap depth) / 2] + (magnetic gap depth / 3) or similar.
Which could lead to BS values like for FaitalPro W8N8-200 FaitalPRO - Professional Loudspeakers Made in Italy
Where Xdamage is less than Xmax. Not a bad driver but I would say that the 8.48mm Xmax is false marketing.
Hi -

Are you sure that the p-p rating for Xdamage is not simply a typo on some data sheet? I have the data sheet for the W8N8-200 and it does not claim the Xdamage is a p-p rating. Also, the suspension materials, at least, appear capable of handling a larger excursion safely than the rated Xmax.
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Old 10th July 2012, 10:50 PM   #23
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Hi -

I actually verified that the W8N8-200 is good for at least half an inch excursion in either direction before, in this case, the voice coil bottoms out on the magnet back plate. Why not? I picked them up effectively brand new for $75 a pop. So, it appears that the ~12mm p-p Xdamage rating on some spec sheets is probably a typo, or possibly applied to an effed up early run?

Last edited by thoriated; 10th July 2012 at 10:52 PM.
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Old 11th July 2012, 01:50 PM   #24
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Quote:
Originally Posted by thoriated View Post
Hi -

I actually verified that the W8N8-200 is good for at least half an inch excursion in either direction before, in this case, the voice coil bottoms out on the magnet back plate. Why not? I picked them up effectively brand new for $75 a pop. So, it appears that the ~12mm p-p Xdamage rating on some spec sheets is probably a typo, or possibly applied to an effed up early run?
Thoriated,
Xmax, Xlim, Xmech, and Xdamage are one way values, not peak to peak.
The W8N8-200 is rated for 12.9 mm Xdamage.
12.9 mm is slightly over 1/2 inch, you have verified the speaker's Xdamage specification appears to be correct.

If you want to verify Xmax, put a dot on the cone, run the speaker at FS, measure the peak to peak excursion when the first harmonic is -20 dB from the fundamental (10% distortion) and divide the peak to peak excursion by 2.
In the case of the W8N8-200, rated for 8.48 mm Xmax, you should measure about 16.96 mm peak to peak when the first harmonic reaches -20 dB below the fundamental.

As was stated earlier, not all companies use 10% distortion as a measurement of Xmax, but for a mid cone as you are writing about (for some unknown reason in a thread about a new 18" B&C cone) 10% distortion will sound pretty obvious.

Art

Last edited by weltersys; 11th July 2012 at 01:55 PM.
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Old 11th July 2012, 02:36 PM   #25
epa is offline epa  Netherlands
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beyma is another one with optimistic values.
i remember an 18 inch with a linier x-max=5(hvc-hg/2), however x-max was stated +-10mm in the specs.
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Old 11th July 2012, 03:06 PM   #26
badman is offline badman  United States
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Quote:
Originally Posted by epa View Post
beyma is another one with optimistic values.
i remember an 18 inch with a linier x-max=5(hvc-hg/2), however x-max was stated +-10mm in the specs.
Not necessarily optimistic

Some motors are more linear than the overhang/underhang would indicate, some are less.

Though it's likely optimistic
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Old 11th July 2012, 03:25 PM   #27
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Quote:
Xmax, Xlim, Xmech, and Xdamage are one way values, not peak to peak.
I was responding to David_Web's claim that Faital spec'd Xdamage as peak to peak and thus it was effectively less than their peak Xmax rating for the W8N8-200 and thus, in part for this reason, their Xmax rating for this model was 'BS'. It is true that I have seen a spec sheet for this model where they did spec Xdamage as 'peak to peak'. Faital's bad, right? Feel free to ask any questions.

Last edited by thoriated; 11th July 2012 at 03:30 PM.
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Old 9th January 2014, 04:04 PM   #28
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Any comments on the 15SW115 vs. 15TBW115? I'm looking at the 4 ohm versions to upgrade the 15's in my ported subs, ~2.75 cubes net, 4 cubes gross, 35hz, driven by an nu6000dsp (~2000 w/ch). The TBW will be about $100-$150 less expensive, 1-2 db more sensitive, while the SW will have the highest "available force per area", slightly more power handling, and be 5 lb lighter. May at some point use in a horn/TH. Thoughts? Looking to place an order soon.

Sensitivity comments:

TH-18 Flat to 35hz! (Xoc1's design)

"Available force" comments:

TH-18 Flat to 35hz! (Xoc1's design)
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Old 9th January 2014, 05:11 PM   #29
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Originally Posted by turbodawg View Post
Any comments on the 15SW115 vs. 15TBW115? [/url]
I have not been able to find any specifications for a B&C "15TBW115", do you have them?
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Old 9th January 2014, 05:14 PM   #30
sine143 is offline sine143  United States
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hehe. I'm sure he means 15tbw100. simple mistake.

regardless, you are gonna be losing your "hump" between 35 an 60 that your HO's currently give you, but also gaining more power handling, and likely reducing power compression as well.
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