Setting up a table tuba outside, in a tent

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Rich4349
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Re: Setting up a table tuba outside, in a tent

#16 Post by Rich4349 »

"dynamic compression of -20 dB at 50 Hz"

I'm not familiar with that measurement spec. Can someone explain that in layman's terms for me?
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

JensToft91
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Re: Setting up a table tuba outside, in a tent

#17 Post by JensToft91 »

Rich4349 wrote: Tue Jul 19, 2022 10:39 am "dynamic compression of -20 dB at 50 Hz"

I'm not familiar with that measurement spec. Can someone explain that in layman's terms for me?
Example:The soundboks is flat from 40hz to 20000 hz playing at 90 dB. But if you turn it up - the bass can't keep up because of various reasons - so that doesn't get any louder, but everything else does. The Dynamic compression graph shows a frequency response at a specific SPL. Normally, turning up the volume will cause distortion - but the designer implements a dynamic EQ to turn down the bass, as the volume is turned up. Thereby having a speaker, that will only play as loud as it's capable off, at all frequencies.

Does that make sense?

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Bill Fitzmaurice
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Re: Setting up a table tuba outside, in a tent

#18 Post by Bill Fitzmaurice »

I understand it, but it doesn't make sense. :)

JensToft91
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Re: Setting up a table tuba outside, in a tent

#19 Post by JensToft91 »

It also used for ported subs. You play the sub at 80 db, and the sub at max output. Then subtract the two curves - that's basically a compression curve. If the port "Chufs" the sub is not able to play the tuning frequency as loud as other frequencies.

JensToft91
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Re: Setting up a table tuba outside, in a tent

#20 Post by JensToft91 »

Found the "Worst case scenario" for the soundboks 2. Pretty impressive for 2x10 inch on battery power. And i don't really get how :shock:

https://imgur.com/a/Sl6ql

JensToft91
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Re: Setting up a table tuba outside, in a tent

#21 Post by JensToft91 »

JensToft91 wrote: Wed Jul 20, 2022 10:23 am Found the "Worst case scenario" for the soundboks 2. Pretty impressive for 2x10 inch on battery power. And i don't really get how :shock:

https://imgur.com/a/Sl6ql
And after calculating how loud i should be able to play with a Tuba HT and 200 W I no longer believe that graph.
200w should be a 23 db gain - 100 db sensitivity at 50 hz, should be 123 db.

The amps in a soundboks is around 70w, or 19db gain. So they're saying that 2 10inch in a vented cabinet is more sensitive than a tuba HT.

Can you confirm?

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Seth
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Re: Setting up a table tuba outside, in a tent

#22 Post by Seth »

JensToft91 wrote: Wed Jul 20, 2022 12:39 pm
Can you confirm?
Your figures are good.

When I saw the graph, without any accompanying context such as methods used to capture and calibrate, "I don't think so" was my first thought. But, I didn't want to open that conversation and make the argument that's it's BS. Glad you caught that on your own :thumbsup:

The breakup in the high end suggests to me that the measurement may have been taken near a boundary. But, that's pure supposition. Just a thought.
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: Setting up a table tuba outside, in a tent

#23 Post by Bruce Weldy »

Seth wrote: Wed Jul 20, 2022 12:55 pm But, I didn't want to open that conversation and make the argument that's it's BS.
That measurement was brought to you by the same people that produce the wattage ratings for Behringer amps. :mrgreen:

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
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: Setting up a table tuba outside, in a tent

#24 Post by Seth »

Bruce Weldy wrote: Wed Jul 20, 2022 1:05 pm
Seth wrote: Wed Jul 20, 2022 12:55 pm But, I didn't want to open that conversation and make the argument that's it's BS.
That measurement was brought to you by the same people that produce the wattage ratings for Behringer amps. :mrgreen:
No, no, no... in this case, it appears something was actually measured. :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

JensToft91
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Re: Setting up a table tuba outside, in a tent

#25 Post by JensToft91 »

He's explaining everything here, including that high frequency dip, and measurement methods.

https://www.reddit.com/r/diyaudio/comme ... t/db7crdw/

I wish I'd just buy a book about sound, 1000 pages long, so i know the answers to all these things. It irritates me, that I firmly believe something must be off - and he still insist that this is completely true.

I just cannot wrap my head around, that we're building huge 12 inch horns - and someone comes along with 15 kgs, with a harness to carry on your back - with measurements of 123 db at 60 hz. On a 12v battery.
But - i've listened to it myself - the sound is impressive at lower-mid volumes, but max it out and you're like: Can you please please turn that shit down? - the bass thins out, and it just starts to scream.

I really like sound - but damn. It's a source of frustration to say the least. I really don't like, when there's something i don't understand.

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Bill Fitzmaurice
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Re: Setting up a table tuba outside, in a tent

#26 Post by Bill Fitzmaurice »

The system is EQ'd up to about 2kHz. That's why it's so flat to there, and why it's not above that. The SPL level is suspect. Knowing the box design and driver used it would take me all of ten minutes to confirm or disprove it.

Rich4349
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Re: Setting up a table tuba outside, in a tent

#27 Post by Rich4349 »

JensToft91 wrote: Wed Jul 20, 2022 2:44 pm I wish I'd just buy a book about sound, 1000 pages long, so i know the answers to all these things.
432 pages, and $26. Go for it!

https://www.amazon.com/Sound-Reinforcem ... 7335&psc=1
2 DR250s, 2 27" Lab15 T-60s, 2 30" Neo Titan 39s, 1 Autotuba...and looking for more!

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Bill Fitzmaurice
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Re: Setting up a table tuba outside, in a tent

#28 Post by Bill Fitzmaurice »

Being from 1988 most of what's in it would be obsolete. No line arrays, no Bluetooth, no DSP, no digital boards.

JensToft91
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Re: Setting up a table tuba outside, in a tent

#29 Post by JensToft91 »

Bill Fitzmaurice wrote: Wed Jul 20, 2022 4:04 pm The system is EQ'd up to about 2kHz. That's why it's so flat to there, and why it's not above that. The SPL level is suspect. Knowing the box design and driver used it would take me all of ten minutes to confirm or disprove it.
All it says on the website is 3x72w amps, 2x10 inch (sensitivity: 96 db.), 1 "compression tweeter" (104 dB).
The box is vented, and is 66cm x 43 cm x 32cm overall.

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Seth
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Re: Setting up a table tuba outside, in a tent

#30 Post by Seth »

So, when's this neighborhood party deal gonna happen?
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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