DevilDriver

nice work dude I'm 21 and I come to work every day thinking "why don't these people work harder and/or smarter?" I guess that's life at a government job!

<<<< Drives an S-10. I'm not totally sure what "acceleration" means. My girlfriend's dad has a 454SS and a Monte Carlo SS. They're both fun to drive.

Hope I get a raise shortly. In less than a month, I have cut processing problems from just over 40% down to under 5%. I like when the bosses are happy with me, but I like it better when they pay me more.

I would send them an email and check. I believe there are some D1 coils that they could use if necessary.

I do like Bill Hicks. Makes for an entertaining listen, though I don't always agree with his points.

How advanced are we talking? Dr. Earl Geddes covers quite a wide range of important topics with supplementary mathematics that you might find useful.

I think anything over 140dB with a relatively musical setup is more than adequate and something you can be quite proud of.

I was quite sure you could buy them now, but I could be wrong. If I remember correctly, you can get more info at [email protected] or speak with Scott directly at [email protected]

Do it. I have been hearing things about the L3's and the L831's for a long time now. I'd like to give them a shot at some point, but I don't think that's immediately in the cards. Scott Buwalda is a very nice and very clever guy.

Just to add to this quickly... Hoffman's Iron Law. It applies to speakers, too! Take a 6.5" speaker for example. They generally take a very small enclosure, have medium efficiency, and lack low frequency extension. Now, it's hard to change enclosure requirements too much for a 6.5" speaker; if we try to gain more low frequency extension, we're going to give up efficiency. If we want more efficiency, we're going to give up low frequency extension. Hoffman's Iron Law applies directly to speakers, the same way it does to enclosures.

Very simple version: 6.5" speakers are, by nature, a bit limited in the amount of output you can achieve. There are a few designs out there that are almost viable for subwoofer duty if you get triplet's or quadruplet's going. The Tang-Band 6.5's are decent, the Mpyre 65X does not seem very dependable, and the EU-700 is, well, from eD. More complicated: There are two really big considerations in terms of output: 1. Linear displacement, determined by Xmax (the linear stroke) and Sd (the effective piston area of the speaker), and 2. Efficiency, determined primarily by Sd, Mms (moving mass), and BL. In terms of linear displacement, a 6.5" speaker is limited in two ways. First and most obviously, it has a small diameter diaphragm. In general, a 6.5" speaker will need roughly 1.5X the linear Xmax that an 8" speaker has to achieve the same amount of linear displacement. Second, a 6.5" speaker's Xmax is usually limited by the suspension. Again, keeping things very general, a 6.5" speaker has a smaller frame, and thus is accompanied by a smaller spider. The spider itself will be limited in the amount of throw it can support because there is not a lot of spider there to maintain a good restoring force over a long stroke. Of course, you can fiddle with the corrugations in a progressive spider to try and gain more throw from the suspension, but you will still be limited by the cone and frame geometry. In terms of efficiency, we already acknowledged that Sd (the effective piston area) is limited on a 6.5" speaker. The obvious positive here is that Mms (moving mass) is quite manageable. However, it is tough to get a lot of BL into a 6.5" speaker. To increase BL, we want to increase the number of windings in the gap or increase the amount of flux in the gap (assuming we haven't approached saturation yet). Increasing flux in the gap is simply a matter of reworking the steel in the motor, ie. going with a taller top plate to carry more flux, going with a wider or taller magnetic stack, etc. However, you still need the windings in the gap to utilize this flux. To do so, it is often easier to go with a wider diameter former. But since there's not much usable spider already (and we'd only be eating up more spider by increasing the former's diameter), we're really digging ourselves into a hole. Also, there are sacrifices in between the two. If you try to increase efficiency, by upping BL, you'll give up some linear excursion in the suspension. If you try to keep a lot of linear excursion, you'll give up some windings in the gap and lose BL, thus losing efficiency. Personally, and this is just my opinion, an 8" is the absolute smallest I would consider usable for a subwoofer, and even then, you can run into similar issues. Hell, there are a lot of 10" subs on the market that have some major difficulties reaching the levels of excursion their motor is capable of.

You get my last PM? The one from yesterday around 4? Guess that would have been around 6 your time. If that's the one, then yes, I have received it and will reply in a bit.

#35 FTW.

Ok, perhaps an alternative approach to this. Burn a CD with a fully clipped signal that has a fundamental frequency of whatever frequency you wish to low pass at. Connect an oscilloscope. Turn down the low pass filter until you see a perfectly round wave. Works like a charm.

Lots of people in the HOP last couple of days.

Which university are you going to? If I remember correctly, the U of C at Boulder is one of the 15 best public universities in the US. I'm currently attending the University of Regina with a major as an Electronic Systems Engineer. Most of my classes have been sporadic since I've been going part-time while working, but I'm attending full-time in January. Hopefully I can continue my good marks and use this as a spring-board towards a full scholarship at a different school, preferably in the US.

Ok, I had a lot to type and say that I'll try to get to tomorrow (got a little distracted listening to vinyl). But the long and short of it is that RMS Power ratings (which don't really exist in the sense that some believe they do) are essentially quite useless when listening to music. The eternal question is: "Can sub A handle amplifier B?" And the answer, realistically, is that you're the one who controls that. After all, it's your fingers on the volume knob, isn't it?

Working here. Some stylesheets (SubBlack for example) have the old link to chat in the header. This used to redirect you to the new address, but now it just comes up as a dead link.

Same rules apply, in general. They just apply in different ways. With a horn, for example, you generally limit low frequency extension if you keep the length of the throat short, and limit efficiency if you keep the mouth area small. You simply must build a large enclosure if you want to keep either of those two, which is why true horn enclosures are usually very big.

Wish we could get some more storm activity here. We're running short of warm fronts strong enough to get much condensation going in the stratosphere.

Don't start until the 4th. I miss school when I'm not there.

I made this analogy in a thread earlier.... A single speaker (no enclosure) is simply a diaphragm with mass on a spring that is driver by an electromechanical motor. The motor is obvious: the voice coil, it's interaction with the flux from the top plate, magnetic stack, backplate, and pole piece. The spring is the spider and surround. The diaphragm with mass is the diaphragm itself (plus the mass of the other moving parts). Now a bass-reflex enclosure behaves on the same kind of principle. The air inside the port is the mass, the air inside the enclosure is the spring, and the motor is the speaker itself. If you imagine this visually, it should be easier for you to understand the answer. The enclosure itself behaves as a low-pass filter. Just like any filter, it has a Q factor, resonance frequency, rate of rolloff, etc. It's the combination of Q factor and resonance frequency that is really the question here, as the rate of rolloff for most bass reflex enclosures is around 24dB/octave (4th order). By introducing two ports with different frequencies at which they resonate, you essentially end up with two different diaphragms with two different masses. Yes, this is in fact a LOT like putting two different speakers in the same enclosure and having them share airspace. It's not a particularly efficient use of the air spring. Note: An aperiodic bi-chamber (ABC) enclosure does work. Using the above analogy, can you explain why?

Looks beautiful. Exactly the type of place I would like to live.

Send an email to [email protected] titled OEM work. Worked for me if you don't get a response. Scott is good for checking the forums, but sometimes I think he's a bit busy.

Most people decide if things are the same by looking at the basket. Tsk, tsk. There's so much more to it than that. Keep the ball rolling, Jacob.