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Old 11th May 2009, 09:29 PM   #31
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Location: Elk Grove, California
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Quote:
Originally posted by tb46
Hi layertone,

Thanks for the threaded insert information, have you done any comparison to the hurricane nuts (Parts Express)?

When you where building the prototype 6" (W6-1139SI?) did you have a chance to do some comparison between TH and other enclosure types, measurements or listening?

The Bash 500 is now on sale for $185.-- @ Parts Express, but excursion does become a problem for anything above 100W/6-Ohm into the LAB12 according to Hornresp. Probably not a big problem with music though.

Regards,
I do have a bag of those hurricane nuts somewhere.

These inserts are the best by far from my experience. Drill / Route out a hole .36" diameter, use a hex to screw in & you're set.

I don't have many subs to compare to...

I did see that EP2500 @ BH, but was thinking about this Mackie FRS 2800 alternative (somewhere around 22 pounds)

http://www.amazon.com/Mackie-FRS-280.../dp/B0013OBUEW

it's not available yet??
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Old 11th May 2009, 11:06 PM   #32
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Quote:
Originally posted by tb46
... excursion does become a problem for anything above 100W/6-Ohm into the LAB12 according to Hornresp. Probably not a big problem with music though.
Not "anything," only 25Hz pure sine waves. This is not unique to the Lab12, it will happen with every speaker, each at their own
critical frequency.

Fortunately, music does not contain high power single frequency sine waves, mainly because they sound like crap. No speaker
manufacturer specs this because it never happens.

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Old 12th May 2009, 02:40 AM   #33
tb46 is offline tb46  United States
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Default Post #32

Hi Don,

Agreed. On the other hand, I'm sure happy I'm not in the business anymore where some fine individual comes in with a woofer under his arm, and the words: "I don't know what happened. It just quit." :-)

Regards,
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Old 12th May 2009, 08:40 AM   #34
MaVo is offline MaVo  Germany
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Quote:
Originally posted by Don Snyder
Fortunately, music does not contain high power single frequency sine waves, mainly because they sound like crap.
This isnt exactly true. As a matter of fact, every musical signal can be described as a certain amount sine waves, added together. Every harmonic and base tone of every instrument is simply a sine wave. Only their combination of frequency, amplitudes and phase values make them unique sounding.

As for high power, quite some music has its loudest signal in the 20-80hz area, maybe except chamber and some girl/guitar type music.

On a sidenote, single sine waves dont sound like crap, as it all comes down to the context they sit it, or else everything must sound like crap, since it is made out of single sine waves.
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Old 12th May 2009, 09:14 AM   #35
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One could add that single Sine waves rarely are present in acoustical recordings (even a large pipe has a lot of harmonics) and that the duration of "mean" sounds comparable to the energy hunger and crest factor of a sine wave is a not often used stylistic device in many genres....
But there are lots of music-genres out there where you have very loooong lasting sine-waves used (Last weekend I was on an industrial/noise event.... 10 minutes 30 Hz Sine wave plus one beat... people there love it, speakers and amps get scared) and crest factors of some signals used in modern synthetical productions often tend towards 3..... (sine wave).

Thatīs one of the reasons why "old standards" of stated power with speakers and amps often donīt apply today, itīs a totaly different thing if one has a "normal rock concert" with a overal crest of letīs say 13 or an industrial event....
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Old 12th May 2009, 03:03 PM   #36
tb46 is offline tb46  United States
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Agree with the general tenor of that too. That's why I believe that you should not exceed the maximum rated (or tested) mechanical excursion in your speaker/amplifier/application combination. And it does make a difference if you are designing for the home or an industrial event. :-)

Regards,
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Old 12th May 2009, 08:16 PM   #37
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The Lab12 has a x-max of 12mm and an x-lim of 22mm. Using this box, at 26 Hz,
Hornresp sims the x-max limited power at 90 Watts, and the x-lim limited power
at 290 Watts.

Tapped horns need DSP. They need it for the HP filter that sets the subs floor and
they need it for the x-over that sets the subs ceiling. The main suppliers are BBE,
Behringer & DBX.

One would think that DSP holds the answer to the "High Power Sine Wave" problem ...

How about it? Do you have the answer?

Don
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Old 12th May 2009, 09:03 PM   #38
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Quote:
One would think that DSP holds the answer to the "High Power Sine Wave" problem ...
Donīt know if I get your point, but one comment to this comes in mind:

DSPs in a Controller are quite usefull, I agree and use them a lot. Sometimes with small setups, I simply use analog high- and lowpasses in my analog x-over, which doesnīt give me the amount of control a DSP-Solution with all the limiters, compressors, phase shifts etc.. does.. But with speakers that have a fairly goo response it still sums up to a good sounding and working system.

The thing I think is much more important than DSP or not: When dealing with signals near the crest factor of a sine wave and having very long durations in these signals, raw Amp Power and keeping your speakers within xmax(lin) is a necessity. While most amps are quite able to boost more power for a short period of time (single basedrum) into your speakers and many transducers cope quite good when xmax(lin) is exceeded for a few percent with a single short impuls, these "stress-situations" realy show the limits of your system. And if these limits are exceeded, failure will occur very quick and the lifespan of yout system is reduced very quick.

So everytime I set up a system stationary in a club or disco, I always choose the outmost save condition when thinking about how big I have to go for it... Using a sine wave generator, the system is fed with sweeps and using the data from simulation and measurement, limiters are set to the point where xmax(lin) is not exceeded. A DSP System allows me to do this in regard to frequency because xmax-is different at various frequencies... Of course, this is "worst case" failure proof and most of the times, a skilled technician could squeeze out much more SPL for certain musik-genres... But you never know when the next DJ has his "selfmade hard-core-techno song" in the CD-Player and thinks itīs funny to play a song with a continous sine-wave at 40 Hz.... I rather choose a bigger amp or add two more subs than risk having one system failure, especialy with unattended systems in a club. A sinewave being the maximum you can throw at a system (except square waves, which would be crest of 1.... but well... we all know what happens with these...) itīs a simple and good way to simulate worst case and setup my systems.


Of course most "normal" music never puts that much stress on speakers and amps. Thatīs why RMS Ratings are often so useless (RMS being sine) when predicting the "power" of your system. If you know what you are doing and know your gear very well, you can easily squeeze more max-power out of a system than with my above method when having a rock event or simple top40 songs...
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Old 12th May 2009, 11:04 PM   #39
fb is offline fb  Australia
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Sabbelbacke, what DSP do you use?
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Old 13th May 2009, 07:59 AM   #40
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Iīm using all kinds, it depends on what people bring up to me or what is already in a club. For my self, I've got two Behringer DCX2496 combined with different EQs (the DEQ 2496 works nicely in combo via digital link) and a few different OEM ones from digisynthetic (many DSP Solutions come from digisynthetic but are labeled differently). @Home and in my lab I am playing around with a Brute-FIR based system, which sadly I canīt take on the road so far.
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