Impious

Stop bringing all of your petty bullshit from another forum over here. At this point I consider this spam as you post identical threads on just about every car audio forum that presently exists.

Are you talking about Scott Buwalda's IASCA presentation vid? He had a custom liquid cooled amp rack with reservoir, but the subs weren't cooled. He starts talking about the liquid cooling system around 6:15

Sad to see. Kevin was a great guy to do business with and offered some outstanding products to the market at very reasonable prices. I've been rocking a Shiva-X in my car for several years and love it.

Personally I would go for something like THIS and run it 2ohm per channel.

I was wondering the same thing My guess would be that he meant he is going to wire one sub per channel @ 2ohm per channel instead of running them mono @ 1ohm. Or he could just bridge the amp and wire them in series for a 4ohm load. Same difference.

Not an audible difference. Not an audible difference. The difference is going to depend on the efficiency of the amplifiers and how strong your electrical system is. The Class D is going to be more efficient with music (meaning at much less than full power) but at or near full power the efficiency difference is probably not that great.

Aren't I always.....

Dirty power, as opposed to un-dirty power? Tell me, have you done any thermal testing and actually measured a temperature difference between a square wave and a sine wave input signal? Comparing the power output for a sine wave vs square wave, the square wave can be up to 1.5 times the power. That's what blows speakers A true squarewave with the same peak voltage as a sinewave would be 2x the average power. Dirty power, as opposed to un-dirty power? Tell me, have you done any thermal testing and actually measured a temperature difference between a square wave and a sine wave input signal? Power is just like underwear. You can only use it so much before it gets dirty and needs tossed in with the rest of the dirty laundry.

The difference is pretty minimal as far as output is concerned. According to WinISD you'd be looking at a difference of around 1-1.5db less output in the smaller enclosure (which is pretty much negligible) over a very narrow bandwidth in the low 30's to high 20's, group delay is a little better in the smaller enclosure. So you're not really losing much of anything by using the smaller enclosure.

There could be dozens of things wrong with the amp, most of which won't show up in a couple pictures. Could be as simple as a solder joint that went bad. Could be a part failure that isn't worth fixing. And honestly, as was mentioned previously.....even fully functional that amp isn't worth a whole lot more than you paid for it. IMO purchase something else to use in your vehicle and if you keep the DHD around, use it as a test mule as you learn more about electronics. Your best friend right now would be google for understanding the inner workings of an amplifier.

That Q looks really high. I'd try to double check your measurement.

Seems like a gigantic waste of money to get a Sundown SAX-1200 for that system. You can find amps that will supply 400w for under $150 and would do the job just as well as the Sundown.

The enclosure tuning has nothing to do with how high the driver can play, those are two totally unrelated issues. Just because the SDC may "like" higher tuned enclosures, it does not inherently mean it can likewise play higher in frequency. What you need to find out is the inductance of the voice coil.

True. The overall shape of the response will be different for the differing alignments without a lot of work involved to match the overall response. I was presuming this was more of a theoretical question about whether same displacement = same output for sealed and IB, which is true (for any 2nd order system). They have the same displacement potential which means the same output potential, even though that potential will rarely be realized simultaneously in the different alignments over their bandwidth without intentionally trying to do so.

What is the impedance of the coils of your subs? If I recall correctly they were offered in both D2 and D4. For headunits - hard to help without knowing your budget. Amplifiers for your speakers - never a bad idea, the amplification inside headunits are pretty weak and cheaply built/designed. That said; whether or not it's worth the expense depends on your goals for the system and your budget. If budget wasn't a concern; yes, I would get an external amplifier for them.

I think if you break it down to the basics of his question, he's not concerned about environmental affects and more concerned about the basis of the physics involved at the driver level. Which tells us that output would be identical as it's determined by the displacement of the driver for a 2nd order system.

No.

Your options would be to wire one sub per amp, or (if the amps are strappable) rewire the subs in series-parallel to a 4ohm final load and strap the amps. Easiest option is just to run one sub per amp @ 2ohm.

PR and ported have pretty much the same roll-off, both are 4th order enclosures. PR's have a little notch in the roll-off because of the resonance of the PR, but that's generally the biggest difference given equivalent alignments. Wouldn't recommend trying to use those Pyle's as a PR As to the original question, PR generally allows for smaller enclosure because the PR displaces a lot less volume than a port, especially in small enclosures. However they can be an added expense to the cost of the system which isn't necessary if space isn't a concern, and it saves the issue of having port noise from having insufficient port area. Other than that performance between a PR and a ported enclosure will be roughly equivalent. Other than that, without knowing your goals hard to give any further recommendations.

Fair warning, I've not read the link on DIYMA. I clicked it, saw it was 4 pages and closed it. Same excursion (and assuming same cone area, meaning same total displacement) at the same frequency in the same environment? Yes, they would measure the same output. See formula previously mentioned in my response to shizzon. No, acceleration would be the same. It would be required to be the same by the fact they were playing the same frequency at the same level of excursion. One can't accelerate "quicker" than the other and both play the same frequency at the same excursion level. If the acceleration were different, one driver would necessarily need to either be moving faster in time (different frequency) or moving farther with each stroke (different excursion level). But acceleration would be identical for two different subs moving at the same frequency at the same excursion level. The only difference would be the amount of power input required to achieve this condition. One subwoofer might require more power input than the other, which would mean one subwoofer had a higher sensitivity/efficiency than the other at that given frequency.....but that's it.

There's not much to debate. It's a simple fact of physics that in a 2nd order alignment output is directly determined by displacement. The more displacement, the more output. In fact you can figure out the (anechoic) potential output for a given displacement at a given frequency for a subwoofer (or any driver) by the formula SPL = 102.4dB + 20log(xmax) + 20log(Sd) + 40log(freq) *Sd in square meters; xmax in meters, one-way Certainly Xmax isn't the loudest possible point, as frequency needs considered also and there's no reason a driver couldn't exceed Xmax........but it's (ideally) the point of the maximum displacement the subwoofer can achieve while maintaining sufficiently low distortion. This ofcourse excludes environmental affects such as the transfer function of the vehicle. But assuming transfer function is identical in both instances, we can ignore it and focus strictly on the drivers and alignments themselves. Nobody cares about SPL competitions and competive "burping" in this scenario. It's irrelevant. We are discussing 2nd order alignments, not 4th order (or higher) alignments that the majority of SPL competitors utilize. Behavior and peak output potential is different between the two. In 2nd order alignments, peak output is limited to peak displacement potentials. We could discuss 4th order (or higher) alignment behavior, excursion isn't irrelevant there either, but that's neither here nor there concerning the topic at hand. In our case, if driver A has 2x the displacement potential of driver B, and they are placed in the same environment, driver A has 6db more output potential.

Not entirely true. With two (or more) speakers wired in series, the back EMF from any of the speakers can modulate the other speakers. This same problem does not exist in dual voice coils of the same subwoofer wired in series. Which is why I said I would disagree with his conclusion that it's better to wire speakers in series than parallel. In fact I wouldn't be surprised if this was the reason for the difference in the video.

I heard similar things as well but mostly pertaining to the Mille line-up, this year's Mille is actually worth the price tag it is sold at compare to the previous Mille line-up. Like I said, depends on who you talk to. I believe the price went down, which may be where that sentiment is coming from. Some people feel the quality and performance went down along with the price tag.

No questions Sencheezy, just me saying why I did what I did, I am very happy with it... I still hope to bring it to a comp or two someday Posting pictures of really crappily located speakers in order to justify your own system design is a logical fallacy. Just because some other people have done stupid things too, doesn't make stupid ideas more valid. "If everyone jumped off a bridge, would you?" That said, I don't see the point in trying to explain why I personally have issues with your current speaker layout. You won't care, it won't make any difference, not worth the effort. If you are happy with it, more power to you. That's what matters and stop trying to justify yourself to us because, first, most of your justifications don't make much sense and second, it honestly doesn't make much of a difference to us as long as you are happy. Do your own thing and bask in the glory of individuality.

:facepalm: I guess my sarcasm didn't come across like I intended. The wires aren't moving cause of current, its because they are sitting right beside a cooling holes on the motor and the air is moving them. He didn't have enough amplitude to create enough air to move the wires. They are moving because of current. When current moves through a wire it creates a magnetic field which is reacting with the motors magnetic field and pushing and pulling the wire. That said I would still disagree with his conclusion. You would want to wire each individual subwoofer's coils in series and parallel the subwoofers together, not the other way around as he suggested.