Introducing SPL Chart

Anything not covered elsewhere.
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Michael Murphy
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Re: Introducing SPL Chart

#271 Post by Michael Murphy » Sat Jul 20, 2013 7:16 am

After 2 cold ones :idea: (in my case light bulb) So what you guys are saying is that you take the max wattage of the driver convert it into volts and then db and this is what you add to the chart when comparing max output?

Srx + 30db
2 T39's vplated 9 + 26=35db



sine143 wrote:85 volts is 30 db, 50 volts is just shy of 26. speaks for itself right there. If the jbl is percieved as louder its because of the inherent percieved higher volume due to harmonic distortion?
Text book wise is this correct?

What converter are you using, this one does not equate to 85v = 30db
http://www.sengpielaudio.com/calculator-volt.htm

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Bill Fitzmaurice
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Re: Introducing SPL Chart

#272 Post by Bill Fitzmaurice » Sat Jul 20, 2013 7:27 am

pumpsfast wrote: What converter are you using, this one does not equate to 85v = 30db
http://www.sengpielaudio.com/calculator-volt.htm
There is no direct relation ship between volts and dB. You have to convert to power. 2xPe=3dB, 10xPe=10dB, 100xPe=20dB, 1000xPe=30dB.
what you guys are saying is that you take the max wattage of the driver convert it into volts
Maximum thermal power is moot, it's displacement limited voltage that counts.
So, what's next on the agenda, how many angels can dance on the head of a pin? :horse:

Michael Murphy
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Re: Introducing SPL Chart

#273 Post by Michael Murphy » Sat Jul 20, 2013 7:33 am

Just trying to understand the reply's, :oops: and yes I agree
Bill Fitzmaurice wrote:Maximum thermal power is moot, it's displacement limited voltage that counts.

Michael Murphy
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Location: Trinidad

Re: Introducing SPL Chart

#274 Post by Michael Murphy » Wed Jan 15, 2014 11:03 am

Chris, are you going to put in the simplexx codes for us?

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Chris_Allen
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Re: Introducing SPL Chart

#275 Post by Chris_Allen » Wed Jan 15, 2014 2:27 pm

Yep - it's on the list. I'm currently rebuilding the site which taking a bit of time.
Built:
6xDR200, 2xT39, 2xT48, 2xJack110, 1xOmni10.5, 1xAutotuba, 1xT18, 1xSLA Pro, 1xW8, 1xW10

chrisj360
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Re: Introducing SPL Chart

#276 Post by chrisj360 » Thu Apr 24, 2014 2:39 pm

Would it be possible to get the T30W27D3012LF with multiple cabs of 2, 4, and 8? Thanks in advance.

Cheers.
2 x 21" T30's with Lab12's
2 x 28" T30's with Lab12's
2 x OTop12 with Deltalite 2512

chrisj360
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Re: Introducing SPL Chart

#277 Post by chrisj360 » Wed May 28, 2014 8:08 pm

If I was to try to approximate the output of multiple T30's (I have the Lab12 loaded and I think the 3012LF is the closest match), I would just add +3 for each cab added like so?



And if I found myself in an ideal setting to corner load and v-plate, it would be +3 for extra cab and the v-plate and +12 for the corner load that would make it look like for a pair (+3 for the extra cab, +3 for the v-plate, and +12 for the corner load):



Four T30's v-plated (+9 for the cabs and +3 for the v-plate) and corner loaded (+12) would look something like:



Is this correct or did I miss something?
2 x 21" T30's with Lab12's
2 x 28" T30's with Lab12's
2 x OTop12 with Deltalite 2512

yigba
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Re: Introducing SPL Chart

#278 Post by yigba » Tue Jun 10, 2014 8:44 am


stevieg
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Re: Introducing SPL Chart

#279 Post by stevieg » Wed Aug 20, 2014 10:01 am

Bill, and others,

I noticed on a competitors page (reputable name that starts with D), that their measurements are done referenced to 2.83V or 28.3V at 10m. Their charts don't offer a listed impedance for measurement, and some of their products are to be used at 4 or even 2 ohms. Shouldn't these references be listed in accordance to Ohms Law? I see the same on some of your measurements, but in your defense, I have seen some of your 4 ohm measurements, more appropriately measured at 2V.

I understand resistance varies with frequency, but have I found yet another way the manufacturers cheat???

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Bill Fitzmaurice
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Re: Introducing SPL Chart

#280 Post by Bill Fitzmaurice » Wed Aug 20, 2014 10:53 am

Unless otherwise stated I use 2.83v at 1m. That equates to 1w into an 8 ohm load. I don't use a power based rating, because the decibel output of a speaker isn't based on power, it's based on voltage swing.

stevieg
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Re: Introducing SPL Chart

#281 Post by stevieg » Wed Aug 20, 2014 11:15 am

Thank you for keeping honest. Those darned sales departments are something, aren't they?

Rich4349
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Re: Introducing SPL Chart

#282 Post by Rich4349 » Fri Jan 16, 2015 6:39 am

In trying to decide which driver to use in which cab, and which width of cab, it sure would be handy to have more (all? :roll: ) of the recommended drivers from the plans, and in more widths. Is this something that is ongoing, or really just not likely to happen?
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

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LelandCrooks
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Re: Introducing SPL Chart

#283 Post by LelandCrooks » Fri Jan 16, 2015 7:51 am

Expensive and exhausting. Testing cabs is not as easy as it sounds if you want it right.
If it's too loud, you're even older than me! Like me.
http://www.speakerhardware.com

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Bill Fitzmaurice
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Re: Introducing SPL Chart

#284 Post by Bill Fitzmaurice » Fri Jan 16, 2015 8:13 am

Rich4349 wrote:In trying to decide which driver to use in which cab, and which width of cab, it sure would be handy to have more (all? :roll: ) of the recommended drivers from the plans, and in more widths. Is this something that is ongoing, or really just not likely to happen?
Do you propose that I build and measure a cab in every conceivable size loaded with every conceivable driver? That most assuredly is not going to happen.

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BrentEvans
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Re: Introducing SPL Chart

#285 Post by BrentEvans » Fri Jan 16, 2015 10:00 am

Bill Fitzmaurice wrote:
Rich4349 wrote:In trying to decide which driver to use in which cab, and which width of cab, it sure would be handy to have more (all? :roll: ) of the recommended drivers from the plans, and in more widths. Is this something that is ongoing, or really just not likely to happen?
Do you propose that I build and measure a cab in every conceivable size loaded with every conceivable driver? That most assuredly is not going to happen.
Bill, just use your holodeck!
99% of the time, things that aren't already being done aren't being done because they don't work. The other 1% is split evenly between fools and geniuses.

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