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.
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.
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?
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?
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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
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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.
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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:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-77.html#post3149604
"Available force" comments:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-103.html#post3176579
Sensitivity comments:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-77.html#post3149604
"Available force" comments:
http://www.diyaudio.com/forums/subwoofers/190635-th-18-flat-35hz-xoc1s-design-103.html#post3176579
I have not been able to find any specifications for a B&C "15TBW115", do you have them?
If that is the case, I'd definitely choose the B&C 15TBW100 over the 15SW115, especially if it is indeed more sensitive, as the increased sensitivity would be a wash for the greater power handling and the 15TBW100 has more Xmax.
5 pounds on a 75 pound cabinet is no big deal, but $100-$150 less cost with more potential output from the given amp is.
Art
Derp.....I mean the 15TBW100-4.
Looks like it's going to be a price difference of about $200 per driver, so I'm pretty much decided on the 15TBW100-4.
Model shows that I should still get a bit of a bump right above tuning, but with slightly lower extension and much more sensitivity in the 100hz-200hz range (more kick drum without EQ).
Looks like it's going to be a price difference of about $200 per driver, so I'm pretty much decided on the 15TBW100-4.
Model shows that I should still get a bit of a bump right above tuning, but with slightly lower extension and much more sensitivity in the 100hz-200hz range (more kick drum without EQ).
Art, thanks sounds good. Total cab will go from about 55lb to about 63lb I think, not optimal but ok. Xmax/Xvar for both is around 12-13.5mm, xmech for SW is 60mm vs. 57mm for TBW.
Same cone area but TBW has ~10% less Mms. B&C spec sheets shows TBW with greater sensitivity in bass frequencies, and the danley comments linked back that up.
Don't have models in front of me, but peak excursion is about 15-16mm on 90v, above tuning.
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I should have wrote the 15TBW100 had greater Xvar (not Xmax) 13.5mm compared to 13 for the 15SW115.
Xmech for SW is 30mm vs. 28.5mm for TBW, the figures you gave were peak to peak
.I'm going to hazard a guess that your inuke nu6000dsp is going to be clipping before a pair of 15TBW100 hit 15-16mm (30-32mm peak to peak), be interested to hear how it does.
I should have wrote the 15TBW100 had greater Xvar (not Xmax) 13.5mm compared to 13 for the 15SW115.
Xmech for SW is 30mm vs. 28.5mm for TBW, the figures you gave were peak to peak
I'm going to hazard a guess that your inuke nu6000dsp is going to be clipping before a pair of 15TBW100 hit 15-16mm (30-32mm peak to peak), be interested to hear how it does.
The nu6000dsp will hit about 100v on a voltmeter with no limiters and no current, but I doubt it sustains that into 4ohms when run off a 115v 15/20a outlet. Regardless, it is a stout little amp, and had no problem pushing the dayton ho's to similar excursion.
The "tendency" is to build for the market, most of the the market for 15" and 18" PA subs is in the 35-45 Hz Fs range, though with smaller VAS than in the days of old. 35-45 Hz still makes for a good compromise between low enough and loud enough.
When looking for low FS drivers, I find there are many more options now than in ye olden tymes.
that is what I meant too
but it appears like that is changing 'again'
35hz Fs seems like becoming the 'sub norm', right now
even 30hz Fs is getting rare
I will not be surpriced if sub drivers with 40hz Fs is the norm next year
"Sub driver" is really an ambiguous term, when the Fs for top speakers in a typical cheap and cheerful package might be 150 Hz, a "sub" with a Fs of 60 is the "norm".
I really don't think there is a "sub norm", there are people not satisfied unless hitting single digit LF at 120 dB, and folks that think a Bose wave radio is as big and low as they want
.Speaker manufacturers make commodities, there will continue to be a large enough demand for low Fs drivers that the average Fs made is really of little concern.
The trend for LF in PAs has definitely dropped in the past couple decades though:
25 Hz is the new 50 Hz - ULTRA Music Festival
Art
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