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Hornsub shootout [message #28056] Sun, 24 July 2005 20:22 Go to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

I'm putting together a hornsub shootout in a couple months and looking at venues right now. There hasn't been a prosound taste-testing like this for a while now, and there have been some new products released, both in the DIY and commercial markets. So I think it's a good time to have a get together and lots of people have indicated they are interested. Watch here for details.

Ground Pounding Action, action, action! [message #28057 is a reply to message #28056] Tue, 02 August 2005 03:25 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

Well guys, we're in. Tulsa Raceway has agreed to allow us to host the event there. The date is Friday, October 14th, from 10:00am to 6:00pm. The price is $10.00 for admission to the raceway, and for that, you can stay all day for the prosound event and through the evening for the racing event.

After 6:00pm, the track will have car races. That night is test-n-tune, when racers are running and calibrating. You can even bring your car and run it if you want. There will be everything there from street cars to nitrous burning ground pounders. It will really be a lot of fun for the price, and you can come and go as you please through the day and evening.

The racing complex has all the power we'll need, 110v, 220v even up to 480v three-phase. So we're set for power. The stadium seating on the north side of the track provides cover, so should we get rain, our equipment won't be exposed.

I'm really looking forward to this. It should be a great time on several levels. We can test and examine our sound equipment all afternoon, and check out the cool cars all evening. Everyone is welcome, DIY and pros, so please come on out.

If you need suggestions on hotels or anything else about the area, please contact me. Information is available on the website at www.ProsoundShootout.com. If you intend to be there and want to have your gear listed, please let me know and send some pics. I'll put it up so people can see who's coming. We'll also post photos and test results after the event.


General test plan [message #28058 is a reply to message #28057] Sat, 03 September 2005 23:45 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

A general test plan is listed below. The specific details of the test plan are specific to the test platform, which is probably going to be Praxis or LMS. David Lee has graciously offered to provide these test platforms and other assistance.


    1) Impedance sweep, cold.

    2) Impulse response.

    3) Frequency response w/SPL at 1W/1M, 10 Hz to 20 kHz (Measured at distance and corrected to 1M)

    4) Frequency response (20 Hz - 200 Hz) w/SPL at 3dB increments to rated power or physical limits. (This will show heat compression and max SPL)

    5) Distortion at 110dB (20 Hz - 200 Hz) and then at 3dB increments from there to rated power or physical limits. (This will indicate the practical limits of the system regarding usable maximum clean reproduction.)

    6) Run heat soak signal 15 minutes at 80% power, repeat steps 4 and 5.

    7) If required, processors can be applied and tests 2, 3, 4, 5 and 6 repeated.

    8) Single horn tested first, pairs or groups tested next if desired.

    9) Subjective listening test using a selection of identical program material played at a referenced sound level.

    10) Subjective listening test using a selection of identical program material played at the maximum sound level of the loudspeakers.


All measurement will be taken from the same place. To save time and insure the least variation, the microphone will be placed at ground level and not moved. All cabinets will be placed on the same mark at the same distance from the microphone.


Re: General test plan [message #28059 is a reply to message #28058] Sun, 04 September 2005 19:19 Go to previous messageGo to next message
Leland Crooks is currently offline  Leland Crooks
Messages: 212
Registered: May 2009
Master
Looks good to me. As one of the guinea pigs my main concern is for driver protection. I'm not a manufacturer who can sacrifice gear for test purposes I'll be relying on the much more experienced testers to monitor input power. I can hear distortion, but thermal problems concern me more. My hl10a's in my tuba 24's are rated @ 300w. I drive them with approx 450-500, but progam material is not like a sine wave sweep or continous pink noise.

I'm really looking forward to this. Especially meeting you Wayne and seeing your thermal heat sink.

Re: General test plan [message #28060 is a reply to message #28059] Mon, 05 September 2005 03:14 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

The test signal for response is actually an MLS (which sounds kind of like pink noise) or swept sine, depending on the measurement system. It is a relatively short burst, so these test signals won't heat up your voice coil very much at all.

The thing to be concerned with is the heat soak signal, but even that isn't going to be run so long that it would likely hurt the voice coil, even at full rated RMS power. If we ran it an hour, then it might though. What we'll be doing is to run at 80% rated power, which in your case is 240Wrms. That will not heat the driver to damaging levels, so it will not harm your driver.


Re: Hornsub shootout [message #28061 is a reply to message #28056] Thu, 08 September 2005 12:10 Go to previous messageGo to next message
PG is currently offline  PG
Messages: 2
Registered: May 2009
Esquire
I cant find any info on the JBL SR4720

Re: Hornsub shootout [message #28062 is a reply to message #28061] Fri, 09 September 2005 01:27 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

It's just like the SR4719, but the woofers are 2242 instead of 2241.

Re: General test plan [message #28063 is a reply to message #28060] Wed, 14 September 2005 07:51 Go to previous messageGo to next message
Rory B. is currently offline  Rory B.
Messages: 2
Registered: May 2009
Esquire
A friend of mine runs his single Tuba 24 at 600 watts with DJ program so whatever you're doing to yours shouldn't harm anything.

Re: General test plan [message #28064 is a reply to message #28063] Wed, 14 September 2005 22:00 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)

Speakers with LAB12 drivers should heat soak using 320 watts RMS (per driver) for 15 minutes. I think speakers running HL10's should heat soak with 240 watts for 15 minutes. These values are 80% of the manufacturer's ratings, and they're safe levels. Much more than that would probably let the smoke out.


Re: General test plan [message #28065 is a reply to message #28064] Thu, 15 September 2005 07:21 Go to previous messageGo to previous message
Leland Crooks is currently offline  Leland Crooks
Messages: 212
Registered: May 2009
Master
Wayne, do you by chance have any of your heat sinks ready for HL10s? I find the whole idea interesting. I'm thinking of pulling a driver and taking some measurements to make a couple. The distance from the driver to the plate is pretty far in a tuba, so my plan is to radiate in the chamber, as the length would radiate most of it there anyway. Possibly turn a right angle to a sink mounted in the horn path .



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