BillFitzmaurice.info

Grant Bunter wrote: ↑Fri Dec 06, 2019 2:04 am ...Seth, you want to save weight in the cab by using something like poplar ply.
Your driver choice alone is costing you over 4lbs (compared to a 3012lf) per cab...

I've recently become aware that the S2012 is an option that fits within the T/S parameters and suits my current goals.

At 4.1 pounds it's 7.7 lighter than the Delta 12LFA, and still even lighter than the 3012LF by 3½ pounds at a cost that's comparable to the Delta 12LFA.

I'm rather excited about that. Just thought I'd share.

Sheesh mate, it's likely to be down in output to the 12LFA as well.
If it was cheaper, might be worth it, but since it's not, the weight saving alone isn't worth it IMHO...

Grant Bunter wrote: ↑Mon Dec 30, 2019 4:00 pm Sheesh mate, it's likely to be down in output to the 12LFA as well.
If it was cheaper, might be worth it, but since it's not, the weight saving alone isn't worth it IMHO...

It's only $40/80 more to shave more than 30/60 pounds off a herd of 4/8 cabinets. In my book, that's a bargain.

What is it about the S2012 that has you say it's likely down in output?

Yes, it's rated 150w RMS, where the Delta 12LFA is rated 200w RMS. Although, I had planned to limit voltage to 30-35 anyway.

And... the S2012 has 10% more Vd, free air response is about 2dB higher on average and it has lower impedance throughout the usable frequency range than the Delta 12LFA. Zmax for the S2012 is right around 80 Ohms, where the Delta 12LFA looks to be about 100 Ohms... and the advertised sensitivity of the S2012 is 99dB, 4.4dB higher than the Delta 12LFA.

Granted, that all changes when loaded in a cabinet... But, I'm not seeing anything that indicates the S2012 would be down in output. In fact, it looks like there's more evidence that it could be slightly improved.

Am I missing something?

SethRocksYou wrote: ↑Mon Dec 30, 2019 4:23 pm

Grant Bunter wrote: ↑Mon Dec 30, 2019 4:00 pm Sheesh mate, it's likely to be down in output to the 12LFA as well.
If it was cheaper, might be worth it, but since it's not, the weight saving alone isn't worth it IMHO...

It's only $40/80 more to shave more than 30/60 pounds off a herd of 4/8 cabinets. In my book, that's a bargain.

What is it about the S2012 that has you say it's likely down in output?

I think it's because the S2012 Vd is only 270 cc. The 3012 LF Vd is 496 cc which means it moves almost 2x the air. You'd need two S2012 loaded cabs to equal the output of one 3012LF.

For me this means more amps and boxes which really costs (and weighs) more in the long run. Additionally, if you're running BFM tops, they'll outrun the subs if you don't use higher displacement drivers. That is unless you want to build double the boxes to keep up.

Anyone feel free to correct me. I'm sure I'm not entirely accurate.

Bryan Cox wrote: ↑Mon Dec 30, 2019 7:24 pm
I think it's because the S2012 Vd is only 270 cc. The 3012 LF Vd is 496 cc which means it moves almost 2x the air. You'd need two S2012 loaded cabs to equal the output of one 3012LF.

For me this means more amps and boxes which really costs (and weighs) more in the long run. Additionally, if you're running BFM tops, they'll outrun the subs if you don't use higher displacement drivers. That is unless you want to build double the boxes to keep up.

Anyone feel free to correct me. I'm sure I'm not entirely accurate.

Grant was talking about the S2012 being less output than the Delta 12LFA. Obviously either of them would be down compared to the 3012LF at peak rated voltage.

You'll probably have to go back a couple pages to get the full context of the conversation. But, to sum it up...

I'm powering them with 30-35 volts and am aiming to maximize system sensitivity and minimize weight.

According to a conversation we had a couple months back, double the cab count with drivers of half the Vd will outperform half the cab count with drivers of twice the Vd
Example; two 3012LF cabs will not match the performance of 4 cabs loaded with Delta 12LFA or S2012. viewtopic.php?f=1&t=25509&p=281245&hili ... rs#p281233

Yes, Vd on the S2012 is "only" 270. However, for the Delta 12LFA, Vd is 243. Four of each would put the Delta 12LFA at a 108 cm³ deficit.

Something will always outrun something else. I'm not too worried about the DR's being capable of outrunning the subs as long as the subs are capable of meeting the requirements of the venue with ample headroom. Doesn't bother me at all if the tops have even more headroom.

Bill Fitzmaurice wrote: ↑Mon Dec 30, 2019 3:05 pm It may be a sine sweep, FFT or pink noise, depending on the hardware and software used.

So, if I used a calibrated mic and just viewed the results on a screen using dBZ, I'm guessing sine waves would show results similar to a published response curve?

Am I understanding Pink Noise correctly, in that it has a "built in" 3dB/octave slope? Where a sine sweep would have a flat output?

Measuring with pink noise you're not using a swept signal. The result using a full bandwidth pink noise signal is almost identical to using a constant voltage swept sine. Which to use is a hardware thing. An RTA that shows the result with pink noise won't work with swept sine or FFT. The main advantage to swept sine and FFT is that you're not limited to a low RTA resolution, like 1/3 octave, as those can measure every frequency should you choose to. But that advantage has limited value, as you can't hear more than 1/6 octave resolution anyway.

Going back to the s2012 vs Delta-12LFa debate, besides weight, the only difference I found was their ability to handle "abuse". The thermal rating and the X-lim are both down on the s2012 compared to the Delta. Of course properly limited it shouldn't be a problem but its something to consider.

With both mentioned drivers being roughly half the cost and VD of a 3012lf, I'm curious to learn the measurable difference between 4×3015lf cabs vs 8×s2012 cabs.
Giving the higher sensitivity and mouth area of the 8 cabs over the 4 we know the max output of the 8 would be greater!

But, Would the difference be worth the extra lumber, pack space, trips loading in & out, ect... ?

Well, that's harder to speculate.

Hey Kevin, good to hear from you buddy

I have the Delta 12LFA's already and have started acquiring S2012's. I'll likely not complete the 4 cabs until March, but I will test them with the 2 different drivers when the time comes.

I'm more than a little curious too... about how close 2 vs. 4, or 4 vs. 8 would be. However, given that I plan to drive them with no more than 35 volts, the point is moot in my particular case unless the 3012LF's provide a sensitivity advantage over the other two drivers.

Who knows, maybe I'll get a couple 3012LF's and do a 2 vs 4 comparison. See how 2 3012LF's at 50 volts measures up to 4 LFA's or S2012's at 35 volts.

I wonder what the most economical way to reliably measure the output and response would be? I live next door to a sod farm, so I'm fairly sure I can use their massive field of grass as a test bed. Would something like REW and a Behringer ECM8000 microphone produce acceptable results? Anyone know?

SethRocksYou wrote: ↑Mon Dec 30, 2019 4:23 pm What is it about the S2012 that has you say it's likely down in output?

For the same reason a S2010 is down compared to a BP102 in a T39, which leads to respective voltage limits of 27V vs 35V.
Best news for you would be I'm wrong!

BTW Driver sensitivity in a horn loaded cab isn't a parameter, it's the cab that dictates response, not the driver.

What do the plans say the voltage limit is for the S2012 in a T48?

Grant Bunter wrote: ↑Tue Dec 31, 2019 3:58 am

SethRocksYou wrote: ↑Mon Dec 30, 2019 4:23 pm What is it about the S2012 that has you say it's likely down in output?

For the same reason a S2010 is down compared to a BP102 in a T39, which leads to respective voltage limits of 27V vs 35V.
Best news for you would be I'm wrong!

BTW Driver sensitivity in a horn loaded cab isn't a parameter, it's the cab that dictates response, not the driver.

What do the plans say the voltage limit is for the S2012 in a T48?

Ah... I see why you went there. That's an understandable statement now. I guess we'll find out together.

I suspect that the reason the BP102 outperforms the S2010 is the S2010 has a limited Xmax of 4.0mm vs. 6.2mm for the BP102.

BP102 Vd 207.4
S2010 Vd 140 (que sound effect: loser trumpet... wah wah wahhhh)

Where, in the case of the Delta 12LFA and S2012, the S2012 boasts the higher Xmax and resultant Vd.

12LFA Vd 243
S2012 Vd 270

The S2010 is no longer listed as a recommended option on any of the Tuba/Titan plans and the S2012 isn't a listed option for the T48 and therefor no recommended voltage limit.

I'm fairly confident I could safely limit the S2012 at 35v. My guess is Bill would be able to say whether S2012 would be displacement limited or thermally limited in a 24" T48 and what an appropriate voltage limit would be. Not sure if he's got any input on it or not. Ultimately, I will find out.

It's 35v, both thermally and mechanically.

Johnny on the spot! Thanks Bill!

Strange Kevin wrote: ↑Tue Dec 31, 2019 1:10 am...I'm curious to learn the measurable difference between 4×3015lf cabs vs 8×s2012 cabs...

You wrote 3015LF, did you mean 3012LF?

If so, I was thinking... you could simulate the situation with the cabs you have. Compare 2 of them bumping against the 60v limiter, then 4 of them and reset the limiter to 42volts. Or, somewhere less than the peaky peak peak. 2 at 20 volts compared to 4 at 14 volts.


... or something like that.