What's to chat about?

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Bruce Weldy
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Re: What's to chat about?

#1051 Post by Bruce Weldy » Sun Sep 12, 2021 3:39 pm

Seth wrote:
Sun Sep 12, 2021 1:35 pm

What was the minimum change you were able to repeatably identify?
Good test....thanks,

I had no problem with 3db. I was 5 of 9 with 1db......but, in a live situation - I'd never have been able to pick out 1db. And since music isn't a test tone - I'm guessing 3db would be a challenge on an individual instrument. The whole mix? Probably so.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Re: What's to chat about?

#1052 Post by Seth » Sun Sep 12, 2021 4:19 pm

Bruce Weldy wrote:
Sun Sep 12, 2021 3:39 pm
Seth wrote:
Sun Sep 12, 2021 1:35 pm

What was the minimum change you were able to repeatably identify?
Good test....thanks,

I had no problem with 3db. I was 5 of 9 with 1db......but, in a live situation - I'd never have been able to pick out 1db. And since music isn't a test tone - I'm guessing 3db would be a challenge on an individual instrument. The whole mix? Probably so.
Exactly my feeling too :thumbsup: And I find that I make my changes in a mix in 3dB increments. Especially when adjusting monitors. And I tell them, "this is up 3dB or down 3dB" to give them a numerical reference. So, if 3 isn't enough but 6 is a tad too much, they ask for 4 or 5 (rare).

And, yeah... if someone snuck behind me and turned the main down 1dB mid-song, I'd probably never notice. 3dB, probably.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
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Re: What's to chat about?

#1053 Post by Bruce Weldy » Sun Sep 12, 2021 4:47 pm

Seth wrote:
Sun Sep 12, 2021 4:19 pm
Especially when adjusting monitors. And I tell them, "this is up 3dB or down 3dB" to give them a numerical reference. So, if 3 isn't enough but 6 is a tad too much, they ask for 4 or 5 (rare).

Grasshopper, you have much to learn. When a musician asks for more monitor - hover your hand over the knob or the tablet without doing anything - 9 times out of 10, they'll say, "Great! Right there!" Once again, their eyes tell their ears that something happened. :mrgreen:

I don't actually do that, but often (especially with using an iPad to mix) before I can even get to the monitor mix page - they say it's better.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Re: What's to chat about?

#1054 Post by Seth » Sun Sep 12, 2021 4:52 pm

I think it's important to distinguish that 1dB in peak output is very very different than the power of a 1dB difference in sensitivity.

I used the term "the power of a 1dB difference in sensitivity" very intentionally, because 1dB in sensitivity can mean the difference of hundreds (if not thousands) of watts.

If you have 4 cabs and want to hit a specific SPL at a specific distance outdoors, say 110dB at 100 feet/30.5 Meters...
Screenshot (119).png
Screenshot (119).png (9.75 KiB) Viewed 175 times
The difference in total power required for the 4 cabs is 384 watts less for the cabs with sensitivity of 102dB vs the cabs with 101dB sensitivity.

Also note that if both cabs have a 55 volt limiter set, the 101dB cab won't meet the goal.

And that's just 1dB difference in sensitivity.
Last edited by Seth on Sun Sep 12, 2021 5:04 pm, edited 4 times in total.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: What's to chat about?

#1055 Post by Seth » Sun Sep 12, 2021 4:55 pm

Bruce Weldy wrote:
Sun Sep 12, 2021 4:47 pm
Seth wrote:
Sun Sep 12, 2021 4:19 pm
Especially when adjusting monitors. And I tell them, "this is up 3dB or down 3dB" to give them a numerical reference. So, if 3 isn't enough but 6 is a tad too much, they ask for 4 or 5 (rare).

Grasshopper, you have much to learn. When a musician asks for more monitor - hover your hand over the knob or the tablet without doing anything - 9 times out of 10, they'll say, "Great! Right there!" Once again, their eyes tell their ears that something happened. :mrgreen:

I don't actually do that, but often (especially with using an iPad to mix) before I can even get to the monitor mix page - they say it's better.
My dad did that all the time, until I told him about it. I'd be rowing through my screens (on PC, tablet, or phone) to make his requested change and before I could even get to the right screen, he'd say "Oh yeah, that's much better".

Now he asks if I made a change yet. And it's really part of why I communicate the changes I make, so they know I've made it and can relate the change to a number.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: What's to chat about?

#1056 Post by Grant Bunter » Sun Sep 12, 2021 5:17 pm

Seth wrote:
Sun Sep 12, 2021 12:23 pm
Two very good possibilities...
Seth wrote:
Sun Sep 12, 2021 12:23 pm
I can sense a 1dB change in a test tone in and A/B test with my earbuds. But, among ambient noise and a music source, I'm not so sure I'd be able to tell you...
I guess I should be more succinct.
I'm talking about live music, or replaying recorded music, through PA.
I might throw on a set of cans to listen to a channel to see if I can tweak, but that's about frequencies, not dB.
Otherwise, I'm with Bruce in that I can't pick 1dB
Seth wrote:
Sun Sep 12, 2021 12:23 pm
I see your point. But, it may be helpful to realize most men are the "go big or go home" type until some experience and/or knowledge is gained...
mmm intriguing.
If we collectively were really concerned about that, we would always throw in the 18 sound option if it was there for any given design.
But we rarely do.
Seth wrote:
Sun Sep 12, 2021 12:23 pm
So, here's something that I frequently overlook (and maybe some of you guys do it too) when making driver comparisons, which is in complete support of your position on the 3012LF/LAB12 debate...
I don't always remember to take into account that different drivers have different response plots and sensitivities and in the case of the LAB12 vs. 3012LF in a T39, it's a significant difference favoring the 3012LF.
Image
Image
I think there is an error here.
And that error is an assumption that the 1 x 12 is a lab12. Since it's a 1 x 12, it could be a Delta12LFA. That would explain the differing results.

The only reason, IIRC, that the lab 12 was introduced way back when, was the rising price of neo's, in particular, the 3012lf. While pricing has since pretty much equalised, at that time, the lab12 was cheaper, for a very similar response to, the 3012lf. It's only penalties were/are weight, and the necessity for a redesign at that time to include chamber reducers.
Seth wrote:
Sun Sep 12, 2021 12:23 pm
Apparently Vd isn't always the king. But still, I understand the propensity of a builder to wanna choose it. The spec we're told to look for (Vd) is greater and the spec the market has engrained in consumers as important (watts) is also greater.
In my mind, Vd is only king if you get to use it all. But displacement voltage limiting, in horns, puts an end to that.
It is still a great way to compare drivers.
Seth wrote:
Sun Sep 12, 2021 12:23 pm
Yup yup. I've picked up on that. Some just want to know what works and go from there. And some want to also know how it works and why. Two different trains to the same destination; one express, one scenic.
Nice line Seth.
Maybe I'm on the 3rd train, the Scenic Express...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Re: What's to chat about?

#1057 Post by Grant Bunter » Sun Sep 12, 2021 5:28 pm

Seth wrote:
Sun Sep 12, 2021 4:52 pm
I think it's important to distinguish that 1dB in peak output is very very different than the power of a 1dB difference in sensitivity.

I used the term "the power of a 1dB difference in sensitivity" very intentionally, because 1dB in sensitivity can mean the difference of hundreds (if not thousands) of watts.

If you have 4 cabs and want to hit a specific SPL at a specific distance outdoors, say 110dB at 100 feet/30.5 Meters...

Screenshot (119).png

The difference in total power required for the 4 cabs is 384 watts less for the cabs with sensitivity of 102dB vs the cabs with 101dB sensitivity.

Also note that if both cabs have a 55 volt limiter set, the 101dB cab won't meet the goal.

And that's just 1dB difference in sensitivity.
I may be wrong here, this may well be the case for direct radiators, but not horn loaded cabs.
It's not the driver that dictates response in horn loaded cabs, it's the design.
ie same or more volume from a "lesser" driver, with less power, meaning sensitivity has risen...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Re: What's to chat about?

#1058 Post by Seth » Sun Sep 12, 2021 10:41 pm

Grant Bunter wrote:
Sun Sep 12, 2021 5:17 pm
Seth wrote:
Sun Sep 12, 2021 12:23 pm
I can sense a 1dB change in a test tone in and A/B test with my earbuds. But, among ambient noise and a music source, I'm not so sure I'd be able to tell you...
I guess I should be more succinct.
I'm talking about live music, or replaying recorded music, through PA.
I might throw on a set of cans to listen to a channel to see if I can tweak, but that's about frequencies, not dB.
Otherwise, I'm with Bruce in that I can't pick 1dB
You know, sometimes when I read things, something will grab my attention and my mind will start thinking about what caught my attention while my eyes keep reading. Then I realize I've read a whole page, but haven't "listened" to a single word following that which caught my attention. Then I have to go back and read it all again and "listen" this time through.

I think that's happened here. I wrote pretty much the same thing you did. But, you obviously didn't "hear" it. You even cut it out of the quote then wrote your reply as though I never said it.

What I wrote was "I can sense a 1dB change in a test tone in and A/B test with my earbuds. But, among ambient noise and a music source, I'm not so sure I'd be able to tell you if/when a music track in a room or outdoors was changed by 1dB. I tend to doubt I'd be able to call out a 1dB change in that situation with any reasonable consistency and repeatability, if at all."


I thought you were pretty succinct when you wrote "Science says most people can't pick a 1dB increase, but some say they can."
"You can't hear a 1dB change (period)" is very different than "You wont hear a 1dB change in a live/recorded show over PA"
I think there is an error here.
And that error is an assumption that the 1 x 12 is a lab12. Since it's a 1 x 12, it could be a Delta12LFA. That would explain the differing results.
Damn, I think you're right Grant! The only other curves on that page that looked similar were comparing two LAB12 loaded cabs. I just looked at the curve shape and made the ASSumption.

Here's the Delta 12LFA and 3012LF (I made a mistake AGAIN! CORRECTION: it's actually an S2012, not a Delta 12 LFA :wall: Time to step away from the computer. LOL )

Image
The two plots are nearly identical. Good catch Grant :thumbsup:

Here's the plot for 2 LAB12 loaded cabs.
Image

If I subtract 6dB from the same points on that plot, I get results that are very similar to the other plot anyway. Do it yourself if you don't believe it:
With the transposed LAB12 results, the 3012LF is still considerably ahead
+3dB at 45HZ, +5dB at 50Hz, +5dB at 60Hz, +5 dB at 70Hz

...and look to be slightly worse than the numbers I came up with for the Delta 12LFA:
+3dB at 45HZ, +4dB at 50Hz, 5dB at 60Hz, 3-4ish dB at 70Hz


So, while there was a mistake (good catch on that BTW) the results aren't any better than what I previously thought either. Upon realizing my mistake, I had really hoped they would be.

Maybe I'm on the 3rd train, the Scenic Express...
Nice :thumbsup:
Last edited by Seth on Mon Sep 13, 2021 12:15 am, edited 3 times in total.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: What's to chat about?

#1059 Post by Seth » Sun Sep 12, 2021 10:53 pm

Grant Bunter wrote:
Sun Sep 12, 2021 5:28 pm
Seth wrote:
Sun Sep 12, 2021 4:52 pm
I think it's important to distinguish that 1dB in peak output is very very different than the power of a 1dB difference in sensitivity.

I used the term "the power of a 1dB difference in sensitivity" very intentionally, because 1dB in sensitivity can mean the difference of hundreds (if not thousands) of watts.

If you have 4 cabs and want to hit a specific SPL at a specific distance outdoors, say 110dB at 100 feet/30.5 Meters...

Screenshot (119).png

The difference in total power required for the 4 cabs is 384 watts less for the cabs with sensitivity of 102dB vs the cabs with 101dB sensitivity.

Also note that if both cabs have a 55 volt limiter set, the 101dB cab won't meet the goal.

And that's just 1dB difference in sensitivity.
I may be wrong here, this may well be the case for direct radiators, but not horn loaded cabs.
It's not the driver that dictates response in horn loaded cabs, it's the design.
ie same or more volume from a "lesser" driver, with less power, meaning sensitivity has risen...
Hmm. I'm a little confused about what you've written here. It doesn't seem to correlate at all to what I wrote.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Grant Bunter
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Re: What's to chat about?

#1060 Post by Grant Bunter » Mon Sep 13, 2021 12:57 am

Seth wrote:
Sun Sep 12, 2021 10:53 pm
Hmm. I'm a little confused about what you've written here. It doesn't seem to correlate at all to what I wrote.
Lol, fair enough.

Where I'm coming from is, sensitivity of the driver is moot in horn loaded cabs IIRC, but may apply more to direct radiators.

Apart from that,
Sensitivity is a calculation. And the specified sensitivity for a a particular driver may not be that which appears in the TS parameters for that driver, because TS parameters are an average across a/multiple production runs. To know sensitivity, you would need to test all your drivers.
To many factors, like power compression, temperature, air pressure can change to make driver sensitivity calculations almost meaningless,
I feel better off using peak output readings, and not worrying about watts at all.
Again, because watts is a calculation you can't make in the middle of a gig unless you can do so in a time that makes the calculation have relevance.

If that still doesn't correlate with what you wrote, it must be the Aussie in me...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

Grant Bunter
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Re: What's to chat about?

#1061 Post by Grant Bunter » Mon Sep 13, 2021 1:14 am

Oh, Seth mate,
Are you basing your calculations on this chart?

Image

Are your calculations out, because this compares different designs and drivers from Bill (T39) and Danley (the labsub)?
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

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Seth
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Re: What's to chat about?

#1062 Post by Seth » Mon Sep 13, 2021 11:35 am

Grant Bunter wrote:
Mon Sep 13, 2021 1:14 am
Oh, Seth mate,
Are you basing your calculations on this chart?

Image
I did. I just took 6dB off the 2x 30" LAB12 loaded trace to identify a single cabs response, compared it to the trace for a 30" 3012LF loaded cab, and posted the difference.
Are your calculations out, because this compares different designs and drivers from Bill (T39) and Danley (the labsub)?
I don't think so (scratching my head though). If anything, using that trace and subtracting 6dB could be slightly generous in the lower end, making the LAB12 look a little better than a true 1 cab response chart. It seems to be completely reasonable method to identify a single cabs response, given the lack of a chart for a single cab... to me anyway.

Are you seeing something I'm not. It's completely possible I'm overlooking something (again LOL).
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Re: What's to chat about?

#1063 Post by Seth » Mon Sep 13, 2021 11:40 am

Grant Bunter wrote:
Mon Sep 13, 2021 12:57 am
Seth wrote:
Sun Sep 12, 2021 10:53 pm
Hmm. I'm a little confused about what you've written here. It doesn't seem to correlate at all to what I wrote.
Lol, fair enough.

Where I'm coming from is, sensitivity of the driver is moot in horn loaded cabs IIRC, but may apply more to direct radiators.

Apart from that,
Sensitivity is a calculation. And the specified sensitivity for a a particular driver may not be that which appears in the TS parameters for that driver, because TS parameters are an average across a/multiple production runs. To know sensitivity, you would need to test all your drivers.
To many factors, like power compression, temperature, air pressure can change to make driver sensitivity calculations almost meaningless,
I feel better off using peak output readings, and not worrying about watts at all.
Again, because watts is a calculation you can't make in the middle of a gig unless you can do so in a time that makes the calculation have relevance.

If that still doesn't correlate with what you wrote, it must be the Aussie in me...
That all sounds reasonably accurate. But, the post was about cab sensitivity, not driver sensitivity.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Bruce Weldy
Posts: 7648
Joined: Fri Nov 27, 2009 11:37 am
Location: New Braunfels, TX

Re: What's to chat about?

#1064 Post by Bruce Weldy » Mon Sep 13, 2021 12:36 pm

Seth wrote:
Mon Sep 13, 2021 11:35 am
Are your calculations out, because this compares different designs and drivers from Bill (T39) and Danley (the labsub)?
I don't think so (scratching my head though). If anything, using that trace and subtracting 6dB could be slightly generous in the lower end, making the LAB12 look a little better than a true 1 cab response chart. It seems to be completely reasonable method to identify a single cabs response, given the lack of a chart for a single cab... to me anyway.

Are you seeing something I'm not. It's completely possible I'm overlooking something (again LOL).
I think you missed his point......the black line on the graph is for a BFM speaker. The blue
line is for a Danley Lab sub - not a BFM speaker with a Lab12 in it.

6 - T39 4-25" 2-22" 3012LF
4 - OT12 2512 Melded/NSD2005
1 - T24
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Seth
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Re: What's to chat about?

#1065 Post by Seth » Mon Sep 13, 2021 12:41 pm

Bruce Weldy wrote:
Mon Sep 13, 2021 12:36 pm
Seth wrote:
Mon Sep 13, 2021 11:35 am
Are your calculations out, because this compares different designs and drivers from Bill (T39) and Danley (the labsub)?
I don't think so (scratching my head though). If anything, using that trace and subtracting 6dB could be slightly generous in the lower end, making the LAB12 look a little better than a true 1 cab response chart. It seems to be completely reasonable method to identify a single cabs response, given the lack of a chart for a single cab... to me anyway.

Are you seeing something I'm not. It's completely possible I'm overlooking something (again LOL).
I think you missed his point......the black line on the graph is for a BFM speaker. The blue
line is for a Danley Lab sub - not a BFM speaker with a Lab12 in it.
The black line is what I used. The blue line is (obviously) of no use to the conversation. Or, at least I thought is was obvious. I should have been more specific. My mistake.

Here it is within the context of where I pulled it from
Screenshot (122).png
Two 30" LAB12 loaded T39's...

Subtract 6dB to identify the values for a single cab. No?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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