Shredhead

Josh, what will you use to EQ your subs if anything?  If you get a chance on your next measurement session will you show the close mic next to the LP response?  That is some wacky looking room gain below 10Hz. 

 

Plan on upgrading my sub amp and hopefully adding my Adcom 555 back into the mix once it's fixed.

Whoa, isn't that the one designed by N. Pass?  What failed on it?  You can hook that up to your sub when it's repaired and get a clean 900W to it for the time being.  I don't know if that thing has any protection circuits on it so maybe hook up a series fuse on the speaker wire but I'm sure it will sound very good. 

I liked it better.  Even James Cameron likes it which is surprising considering he crapped on the last 2.  http://www.cinemablend.com/new/James-Cameron-Watched-Terminator-Genisys-Here-His-Review-71898.html

They copied a couple of scenes from the first one note for note which was cool to see. 

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Max: looks like soft limiting but it is well under a WCS and when I zoomed in on the highest

level parts it didn't look like they were playing with square waves.

http://data-bass.ipbhost.com/index.php?/topic/425-analyzing-waveforms-of-heavy-hitting-movies/?p=10657

Terminator Genisys -Atmos track defaulted to 7.1 Dolby TrueHD

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Pixels -Dolby True HD 7.1

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Does anybody on this site have Atmos yet or is it just me?

 

Oh wait.... a lot of youz still running 5.1 audio.

How dare you.

I looked on the back of the San Andreas bluray to try to find out the soundtrack description but all it said was Atmos.  I was curious about what it defaults to for us single plane peasants, TrueHD or DTS MA and how many discrete tracks.  The menu was no help either.  Anyone know the story on this? 

Shred,

 

Does Jurassic World clip?

 

JSS

Not sure but I would guess not (still haven't watched it).  The level of the sub out that I took seems weak compared to most other movies like SA.  I don't know if that means the overall level of the movie is below average or just the sub band.  The waveform looks pretty dynamic so I would guess if it does play with square waves it would be toward the end in short bursts. 

I didn't watch either, just went through them quickly and capped the hottest parts cause I was curious.  Looked good enough to be a JP movie to me.  For a little while I was like "They are going to have DINOSAURS in this DINOSAUR movie right?  Hello?"

^^^continued

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Jurassic World (7.1 DTS MA)

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...

Note to mods: please move these lab shots to the appropriate threads when you get them going.

SAN ANDREAS

(Atmos soundtrack)

(taken from sub out with 7 channels re-directed)

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Excuse me, Hollywood: Earthquakes aren't filtered at 20Hz.

While a circuit can sustain far more than its rated current for brief periods of time (as discussed earlier in this thread), the maximum current draw a circuit can sustain indefinitely is actually 80% of its rated load, i.e., 24A on a 30A-nominal circuit.

k so that's a max possible total of 5760W with 2 24A sustained circuits.  So since Luke measured 6363.28W max power out of the amp I guess the efficiency is >110%.    What Luke and Josh tested are just things to give us an idea of what's really happening with the amp.  No one said any of these tests are completely accurate and you can sit here and nit pick them all to death because you need a lab full of tools to do get an accurate picture.  Unless you're offering to buy Luke an amp meter or to contribute some data of your own that has to do with this thread, kindly get the fuck up off my nuts. 

While a circuit can sustain far more than its rated current for brief periods of time (as discussed earlier in this thread), the maximum current draw a circuit can sustain indefinitely is actually 80% of its rated load, i.e., 24A on a 30A-nominal circuit.  Either way, you have no way of knowing how much current the amp is drawing from the mains when the amp taps out.  This quantity has to be measured separately.

 

Yeah, no shit SME but Luke doesn't have access to a lab setup does he?  This is what I'm talking about with your annoying shit.  When are you going to step up and show us how it's done then so we can nit pick the crap out of your data?  Oh yeah never, I forgot that will never happen.  Just more of you flapping the gums.  Thanks for contributing nothing yet again and seriously, fuck off with quoting my posts. 

Your response is disappointing, and you mistake my critical peer review for excessive ego.

I'm not an engineer or a scientist but if I was why would I want you to review anything I did or wrote?  Are you an expert in amplifier design?  Are you here to share your experience in amp testing?  You seem to contribute nothing to this site except an argumentative opposing view.  I'm good on that.  The shit gets old.  Save all of your "help" for someone who wants it, I'll be just fine without your critique. 

Enjoyed this site immensely and thanks to everyone who's given advice along the way. Sold all my gear today so will no longer be able to vote! Pursuing another passion. Really great site here and I've spent many hours following other threads because they hold much interest even though much of it went over my head. Bosso if I can get one of your systems to Australia I might be knocking on your door when I decide to get back into it.

We'll miss ya Aj, hope you'll still pop in once in a while to see what's up.  I have to ask, what's the new passion you'll be getting into? 

                                       Volts                 Amps                 RMS Power               Peak Power (approximately)

Max Clean:                   86.5V                 71.08A                6148.1W                     8693.4W

~1dB into clipping:      88V                    72.31A                6363.28W                   8997.7W

Your outlet power is 122V x 30A =3660W times two breakers is 7320W of total power (RMS) available to your amp.

That means that at max clean power your amp is ~84% efficient driving 1.217 ohms.  Not too sure how 2 channel testing would change things, efficiency might go up and power per channel will go down perhaps.

Thanks for doing that Luke, good contribution to the thread. That is impressive sustained power @27Hz.  Your driver had to be about at it's mechanical limits?

If Brian O. happens to read this post, correct me if I am wrong about any of this and I have a question:  Have you comparison tested your amps using high voltage/high impedance vs. high current/low impedance?  Is there a difference in efficiency or distortion numbers? 

You owe me one shreds...I did this with the wife home because I was so curious... 

 

I measured a steady 86.5v without clipping and registered 131.1db with one Othorn at the LP (compromise with the wife was that only one horn would be on =)  ).  

Going up one more DB in the volume resulted in 88.0v, 132.0db, and clip lights.  

Hahaha, awesome.  A couple questions: you have a 240V 30A line?  Is that two 15A 120V breakers?  I think I asked you that at the GTG but I forget.  Do you remember how long the wire run was and what gauge you used for the power line?  And were you running 1 channel only for the song part because the amp doesn't bridge right? 

It's a track by Bass Launch called "Earth".  This one particularly is the "low and slow" version.  Most of the tracks on that whole album are similar to this.  I'm not sure if there would be any difference between playing my 6 second loop of this track or a 27.5hz sine wave from REW.

 

For the voltage, do you want me to capture the voltage at the binding posts while playing that track loop at a level where the amp begins to clip?  The Fluke 117 is called a "True-RMS" meter, so I'm not sure if simply getting the AC voltage is all you're after. 

Stick to the song track since you already know it's impedance for sure measured with your meter.  Your meter doesn't do peak so just the steady RMS reading is fine with it set to AC auto range. 

Last I heard Gage was going to send that amp to notnyt to test whenever he gets the free time but for all I know you might be right. 

 

 

I also suggested this could have been the result of an overly sensitive DC protection circuit.  I know David's amp had a looser setting than the first release as I was responsible for the first adjustment, but it has been pushed to a lower/longer time constant over time, and I've been talking with Brian about eliminating it entirely as the other diagnostics in the amp would detect the issue upstream in the circuit, making it a belt & suspenders situation.  I suspect the brief cut-out Josh noted was also a DC protection circuit, but can't be certain without Brian bypassing the circuit and letting Josh run that sweep again.

 

I think it is more likely a current protection circuit because when Josh tested at a higher impedance there was no muting with the same burst/long term tones.

So a GTG at Beast's?  Woo hoo!  Is Dgage mailing that amp so we can get to the bottom of it finally? 

 

 

 

And of course, if someone can produce substantial evidence that the SP2 chokes so easily, then we will have more to talk about.

 

I'm sure of two things. 

1. we can count on you lording over the discussion when that happens, Subject Matter Ego.

2. you won't be the one who contributes the data.

That looks like some weird music.  Nothing else in the bass range except low fundamental clean sines.  Unusual.  What is the artist/track? 

Send your wife on an errand and give me the voltage reading. 

Yeah that's what I want, a random voltage.

Comon man, keep up.  You wrote: "So, I tried another track, this one with several seconds straight of ~27hz, and the reading was a repeatable 1.217 ohms.

I pushed this track to levels over 135db at the seats with just the Othorns playing and it resulted in no clipping and idle fans.  Amp barely warm to the touch."

Then I posted: "Volts and amps draw was what for 135dB?"

So... play the several seconds of 1.217 ohms at 135dB and measure the RMS voltage.  Tell me that number and I'll tell you the power.  No fibbing. 

Tell me the RMS voltage for the 1.2 ohm part and I'll do ohms law for you.