Bossobass Dave

Here's Raptor with 3 boost SEQSS curves, HPF set to 'No':

Check out Dave's Mariana in Josh's room:

At the outset, I've never been a fan of the XXX drivers. Way too big, way too big a box requirement, way too much $$$. Looking more at the HST-18/UXL-18 is more my speed. There's not much difference as far as what EQ is required to get flat in your room. It's simple enough to project the HST-18, for example from anechoic to same placement of driver/mic you used to generate the in-room graph posted earlier: Done quickly, but I'm not gonna be too far off. A typical humped response (part inductance/part small box) is down around -7dB @ 20 Hz, whereas the low Q drivers are down more like -15dB @ 20 Hz. Pull down the hump of the long throw mid q driver or pull down the top end of the mega-motor low Q driver. A wash in the end, IMO. You're showing tons of room gain. Since the Fosgate is down -25dB from cross to 10 Hz

It certainly looks cool but... As a candidate for HT, it's mounting depth is prohibitive and, as with any sub driver design, the higher the motor strength, the lower the Qts. It's Q is so low, it never achieves a 2nd order roll off. The HS-24 trounces it for 1/2 the price and has far less disparity between the bottom frequencies and cross. A quad of HST-18s in dual, dual-opposed boxes is a far better system for the same dough... Etc., etc.

PIXELS Just watched the whole flick at reference with the subs running a few dB hot. Stupendous low end. Tons of it. There are 2 scenes that taxed my Raptor system 3. I won't say which until there's a pinned thread, but I will say that one of them has strongest effect frequency content centered at 4 Hz but with a spread of simultaneous freqs to cross. BRUTAL! This soundtrack is huge with content to 1 Hz, at least, and the musical score is great as well. Awesome mix. Jumping the gun and voting 5 stars, with it's hands tied behind it's back, and a strong buy, which I shall do tomorrow afternoon. I've been waiting for a soundtrack like this for a long time. I was beginning to think the filter monster had bitten every sound man in the movie biz.

We found Pixels to be no sillier a premise than Avengers or Mad Max or Jurassic World and typical of the majority of the Adam Sandler library. As a MWB, the caps speak for themselves. More specifically, the low end effects, which you can see are extremely wide bandwidth, are quite unique and easily discernible as such when audibly scrutinized. It's a heavyweight. I don't know about the level because my system is in test flux and not calibrated and my PC for SL and REW is being replaced and not on line, so I inquired above because it might be required pre-info before the bassheads grab this one and let it rip. Sound design and re-recording mixer Steve Boeddeker who did sound design for Tron:Legacy, Hellboy and X-Men has been around the block, working his way up. He goes back to the 90s, including Sound Effects Editor credit for Fight Club. Looking forward to more Design/Mix work from this guy. Pixels is a contender for MWB of the year, IMO, script/score/acting quality notwithstanding.

Hmmmm Where's the data for Mad Max, Jurassic Park and Pixels? Nube, Max, you guys retire? I just had Paul graph some scenes from Pixels, which has some srious content. I had previously seen hide nor hair about it. Bummer.

It might be worth trying the exercise of repeating the test with the VPL set to decreasing values until it actually kicks in? BTW and FYI, Music Group (who has owned LG since April of this year) is Behringer.

Just finished watching the Jurassic flick. There's low end in it, but the movie is for 3 year olds, IMO. Other than the big 'osaurs, the movie is a giant snooze. Where's Jeff Goldblum when you need him?

I agree that something is not right. Did you try bridging the amp?

Lab Gruppen (1979) ==> TGI Group (2000) ==> TC Group (2002) ==> Music Group (April 2015) Random foreign forum post: The IPD-2400 is purportedly made in Taiwan. Most user-reviews like it for SQ, size and lower price (vs typical LG pricing), but it's obviously not an output monster.

Trying to figure out your math here... There's "almost twice the amps", but less than 1dB more watts, not "more than twice the watts". Very little compression in dBSPL clocked. Am I missing something? The key here is the "more than twice the amps" part. Two things happen as the load increases (impedance is lowered); 1) THD increases and 2) efficiency drops (more heat). I think a repeat with SL running would show the difference in THD. Although approximate, the relative difference might be noteworthy, IMO.

Having been on many chat rooms and forums over the past 17 or so years, it's always sad to see great contributors to the hobby move on. I understand the desire to follow your passions and laud it, Take care and drop in once in a while, my friend. We'll make sure there's a system in the corner stamped "Aj72" waiting for ya.

Your argument is stupid. Try to misread that as critical peer review.

Again, besides the vague comparisons, this is the other point of my posts regarding stupid-heavy loads presented to an amplifier, generally speaking. The scenario is not likely to be repeated because it's not an optimum system configuration. Yes, pro sound is the market for the rackmount amps and no, they never have to reproduce single digit source at max output into <2 ohms from a bridged amp. Why would anyone recommend a system that presents <2 ohms per bridged amp? So, maybe you can tell me what I'm missing in the differences between a high voltage, high impedance system vs a high current, low impedance system? Our tests say <3 ohms per bridged amp results in audibly degraded reproduction. Maybe our tests are seriously flawed. EDIT: I just caught Luke's post. Congrats, Luke! Great exercise and results. I'm sure Paul will follow up looking for the rest of the details like what mains, distances, one channel driven, etc., but thanks for the great effort.

This is the sort of post that prompts a reaction from me. Where are the parts for this robust protection circuit sourced from, what makes an over-current circuit any more robust or more expensive, what cheaper amps produced in China are you referring to and what makes their protection circuitry my less robust? In the context of the discussion, specifically regarding over-current protection, making such a circuit more "robust" simply means raising the peak current value of the circuit before it trips. Nothing superior about it. Nothing so much more costly about it. Is it a good thing? The output impedance of the A-14K is approximately 0.020 ohms. Say I have 15 feet of 10AWG wire from the amp terminals to the Raptor terminals. That raises the output impedance to 0.35 ohms. Into a nominal 7.4 ohms (Raptor System II), the damping factor is approximately 220. Into a nominal 0.70 ohms, the damping factor drops to 21 and the signal loss increases by at least 5% Is that sort of difference in damping factor audible? Is there a quicker rise in THD with the lower impedance load? Does the spike in heat affect the longevity of an amplifier whose cooling scheme may not be considered optimum for higher heat? Is there a change in efficiency as load impedance drops? These are the more pertinent points to address rather than how some protection circuit results in a price that exceeds any amplifier made in China (which translates to virtually every other amp), IMO. I'm happy to know that somewhere on the net the FR of the SP amps is posted. Maybe you'll actually follow up and post it here. We have a thread for that if you're so inclined to add the data there. I fail to see where it is a negative thing in any way to provide the info. To address the insanely insulting post that any mention of the GTG experience is SP-bashing; the amplifier used at the GTG belonged to a SP OEM manufacturer (or soon-to-be at the time if he wasn't already). No one else there knew much of anything about the amp, especially not a flashing prot light on the back panel. Apparently, David chose not to pursue the cause for personal reasons. So, if anything, I guess it was on you to follow up since you were the only person with tech comments after the situation was mentioned and are also a SP dealer and end-user. I've been interested in the SP amps since their launch in their current iterations. The situation at the GTG is being referred to in this thread as one that supposedly should not have occurred or sent shock waves throughout the interwebs. Well, hopefully we have enough on the ball to know that that is nonsense. No one designs protection circuitry for a situation that will never occur, right? We all thought what happened at the GTG was noteworthy. If I were considering purchasing any $3,000.00 amplifier, it's certainly information I would like to be made aware of. I think a lot of Brian and have followed his SP career for much longer than probably anyone here and I believe the SP line, as it has evolved to the present time, is an outstanding achievement. I'm just put off by the cheesy comparisons to alternative choices or their countries of origin to justify the price.

Open to it and ready to head your way, bro. It's always a pleasure and I've been wanting to meet Josh for years. LMK the date and I'm there.

For the record, if it were an A14K (which it wouldn't have been), everyone would know the reason why in short order. There would be no mystery. Josh, seriously, I'm up for raiding Brandon's place before it's -30 degrees up there in the Swiss Alps.

Sounds like a plan is coming together...

If everything about low frequency reproduction could be assumed, this forum would obviously not exist. The question is why would anyone design a subwoofer system to operate at 1 ohm nominal. I see no advantages, only disadvantages. How much transient burst current a breaker can allow before tripping is not predictable and not relevant. The SP-2-8000 muted when operating on a dedicated 120V-30A line at Brandon's GTG, both channels driving a 1.7 resting Re reactive load. Since Paul and I weren't there to test a SP amplifier (didn't even know one was there until Dave Gage pulled it out of his car and brought it in half way through the GTG), there was little more time and equipment available to do more than measure resting Re and speclab cap the scenes being played. I know this; the A14-K amp bridged, driving the series-wired VCs at a resting Re of 3.4 ohms with the same 120V-30A line would have been easily able to damage the HST-24 driver without going into protect. There was speculation by Seaton after the fact that it was "line sag", but there was no indication that line sag or brown out was apparent during the rest of the GTG. Still, no measurements were taken. I still don't know if there is overcurrent protection in the SP line of amps or how one would know what is going on with the amplifier since there are no indicator LEDs on the front panel besides a power on LED and the rear panel only has single signal LED and a clip and a protect LED. Protect can mean several things. I don't see the difference between the songs being played at the GTG and the song you mention playing, but, there's no data here beyond your description. A speclab cap would be nice. Actually, the mic'd version (that clocked 135dB) and a loop through version for comparison. And, the measurements Paul asked for as well as a FR at the mic that clocked 135dB. That data would be helpful vs the 'so and so says so' kinda answers. No one has posted a FR of the amplifiers as well. I really don't get that. It's pretty much the whole shootin' match when making claims about subwoofer reproduction. I know that you filter the low stuff out, but the rest of us don't so it's pertinent to know if the amplifier is doing that for you. Since this thread is about the SP amps, I thought it would be nice to get to the bottom of these issues. I mentioned in my first post in this thread that I don't lend any credence to the SP comparison tests and that sort of info is a marketing ploy to justify the relatively high cost of the SP line, IMO. I'm much more interested in the sort of comparison Josh did in this thread, except that there is still a lot of missing data, IMO, YMMV.

I missed this gem ^^ My kids are grown men but when they were young if someone asked them a question they didn't have the answer to they just said "I don't know" or went and got the actual answer. 8,000 watts into 1 ohm requires 90 amps of current. So, you might see why someone reading your name-dropping, spec-citing posts might ask for actual measurements, or might be curious about your 220V/30A circuit and SP 1-6000 driving the iPAL/DIY Horn? I appreciate what you've posted as a start.

I agree with this, except for the <1 ohm stuff. Really all that needs to be said. That's what I'm sayin'. The best you get with SP is a 6KW bridged amp. Adding multiples... can be done with any bridgeable or full bridge monoblock amp, and <1 ohm operation... not much relevance to HT or any audio scenario, actually.

"Your argument is stupid..." What the fuck? Is this Luke using SME's account? Into a 0.7 ohm load, no amp delivers 5KW long term or any term on a 30A line, 120V or 240V. At 1 ohm, volts equal amps and 30A is the limit, long term. There may be a 10% safety factor long term in the breaker, not 500%. That was the point of my post. It's not an argument, it's math. The SP-2-8000 was not 240V, it is 120V. On a 30A dedicated line it repeatedly shut down into a nominal 2 ohm load per side using ULF-centric source. Brian's test results claim 100% efficiency since the rated output equals the tested output, although no mention of the input signal are cited. Be that as it may, my beef with the test is that he has a 14KW amp (rated, in bridged mode into 4 ohms) and tests only a single channel whereas his SP amps are full bridge amps. The proper comparison is to bridge the amp being compared to, as Josh did. Your post is bullshit. (Hey, that was fun. Now I know why you guys like to do it regularly.) If you have the amp, can you post the measurements and the measured frequency response, or is bullshit gonna be all we get here?

In reality, the mains is the final determinant for performance. Amplifiers aren't magic boxes. They can only work to the voltage and current limits provided. The long term output is definitely limited by volts * amps = watts. In a perfect world, if your mains can feed 120 volts into 4 ohms, the current draw is 30 amps and the watts is 3600. Now, if you present a 1 ohm load, the volts drops to 30V with 30 amps current draw and 900 watts. Push for more and shut down occurs. We saw that at your GTG with the SP amp while playing ULF-centric source. Any amp that can handle 30 amps is a great amp, but reality has to be a part of the conversation.

If you're gonna cite an impedance minimum at 2 specific frequencies (that aren't from a measurement of the same driver in the same cabinet), and claim there is no problem from the amplifier at that impedance minimum, then you need to show that the amp has no problems at maximum output at those frequencies with measurements that verify the current draw and impedance. When you play a soundtrack the impedance is the average of all the frequencies being played, it's not that the lowest impedance is dominant. Even if the amplifier somehow has unlimited current capability (which, of course, it doesn't), your mains limit the current draw. So, no, the data presented so far doesn't do it for me. Hope that's OK. Josh wrote: And honestly Luke, if you're gonna continue to answer my Qs with irrelevant one-liners, I'm really not that interested in the data.