[Technic]

The Earthquake people should know the OEM enclosure size for sure...

[VP Electricity]

Should.

But I doubt it. You ever MEET the Earthquake people?

[Lee Rambler]

earthquake people as in the people with them in their cars? or as in the engineers at earthquake? I rather doubt the engineers at earthquake know or care about the oem enclosure in our cars, the woofers were not purpose designed for this application. the people with them in their cars? would be important for them to know, agreed. doubt many if any measured the enclosure to run a model on it with the earthquake driver, guessing it went something more like "awsome it fit! this is way better than the bmw speaker". and as long as they enjoy it more, great. Not sure I'm of the same opinion, but I'm not the one listening to them everyday. I had hoped to find the info somewhere from someone who did put them (or another driver in), but I haven't seen it anywhere. Best I could do was guess at rough dimensions from pictures having a few rough reference points like the 8" diameter of the driver. I may not end up doing any better when I pull it either truthfully - I'm sure I can derive the volume of the part I pull out, but I have no idea what else is in there...

[VP Electricity]

Being acquainted with the people at EQ, I can tell you they sell this driver as being specific to this car, and as being "perfect" for this car. If you asked senior people the volume, I suspect they would guess rather than admit they haven't measured it.

But they are very familiar with the use of the SWS 8 by so many forum members.

[Dackz]

I thought earthquake made the OEM woofers and the SWS-8's were just upgraded versions of them with better power handling and better excursion for more SPL??

[VP Electricity]

I think EQ spreads, or implies that - but I don't believe it. EQ would never qualify as a Tier One.

[Technic]

Originally Posted by Dackz

I thought earthquake made the OEM woofers and the SWS-8's were just upgraded versions of them with better power handling and better excursion for more SPL??

That's what apparently they said when some forum member asked them...

[Lee Rambler]

so earthquake is claiming they have an oem relationship with bmw? I find that hard to believe... or are they saying the same manufacturer who makes the BMW woofer also makes theirs? That would be more believable, though I'm still not sure I believe it... just upgraded for more excursion - oh wait, completely different basket (and material), different cone (and material), different motor setup... yeah, just upgraded excursion.

I'm not saying the earthquakes are complete junk or anything, I think they have a specific purpose and probobly serve it well - I'm just not sure a driver that also needs to play midbass is it.

[Lee Rambler]

looks like the "enclosure" counting the frame rail is more like 1.4ft3 and "sealed", see my thread with pics. I had a scope back in the rail, and there is expansion sealant at the joints. Granted it still doesn't help the midbass of the earthquake, but it at least makes me feel better about them being able to reproduce some low bass in that size enclosure. Not for me still....

the oem driver is actually fairly impressive having a look at it. I would guess that xmax is in the neighborhood of 1/2". I rather doubt the bad noises I'm hearing are them bottoming, they don't seem to have a "hard" bottom per se, so I'm wondering if it isn't the enclosure/metal floor pan I'm hearing making bad noises?

[VP Electricity]

The enclosure is decoupled from the floor with a rubber "freeze plug'-looking foot.

I'm not clear how you determined that the duct vents into a second sealed chamber... but if it is sealed, the duct cross-section is small enough for an 8, especially an 8" with more excursion, that the air compresses across the duct, and you end up with a impossible-to-model enclosure with an aperiodic link between two sealed chambers.

This morning I will be running a z curve and looking for resonance coincident with a vent.

[Lee Rambler]

cool, I think that will be really helpful.

I saw the rubber "foot", but the whole frame rail part of the enclosure and floor pan is rather thin gauge metal that may be resonating to the point that it could be making the sound I am hearing. After actually having the oem driver in my hands, I rather doubt it is hard bottoming that I am hearing. There seems to be suspension limits prior to coil bottoming.
(or topping as I suppose the case would actually be =) ).

as I'm sure you've already seen, the opening to the frame rail is pretty much the whole size of the plastic "enclosure" part - 7-8" wide by 1.5" or so tall. I'd say the whole plastic enclosure is easily as much as if not more of a choke as the entrance to the frame rail. I can't say for sure how well sealed the whole "enclosure" is, but there is no port to speak of, nor does it appear to be any kind of t-line (which was my origional suspicion). There was definitely efforts to seal it, how successful they are is hard to say. If you have different drivers in yours, you can probobly tell by pressing the driver in and seeing how quickly it rebounds. With the oem woofer this can't be done because of the fabric over the driver, and I can't even pop it with a battery to see - though maybe with a flashlight at the right angle I'd be able to see.

[VP Electricity]

Either the sub enclosure is tuned for 30 or it is a sealed box. Either is possible. There is a peak in my RTA and FFT analyzer readings at 31 at the listening position (EQ and xovers off). There is almost no perceptible cabin gain - curve is pretty darned flat to 30 - so I suspect that cabin gain is what's getting us there.

I am not gonna pull the SWS8 today. But when I swap them for ADMW9, I will do a freeair Z sweep and see if the peak is different. The listed Fs for the SWS8 is 30, so if the enclosure is tuned for 30, the peaks would stack. I've never tested the Z curve of a freeair SWS8, so I can't comment.

But it *might* be sealed. If it is, I believe that with a longer-travel woofer, you won't be able to model the enclosure in software. Glad I like pragmatic empiricism

[Lee Rambler]

good info, thanks. you didn't by chance find and weird panel vibrations while checking did you? I had some full band noise playing while putting the front speakers in to check things, and figured I'd listen around the frame rail for any of the noise I'm hearing at high volume. Definitely some resonance, not sure if it's it though... have you ever used mw266's or mw267's by chance? curious if you have, what your thoughts were on them. I take it you like the admsw9's (logical guess since you are planning on putting them in)?

As suspected, the midbass with the quarts is much better and has a smoother transition into the underseat subs. They did take a bit of basket modification to make fit though (not just the lip at the screws, but part of the basket - plastic sort of thankfully - had to be ground down so as to not rub on the window/track. FYI for anyone else considering them. Need to play with the tweeter level a bit yet, but so far pretty happy (I started at -6db on them which may be a bit much - not as harsh as I had expected from previous quart experience, think I'll end up at -3db). The doors were MUCH easier to take off than I had expected too. Now we'll see about the rears...

[VP Electricity]

Any less-efficient speaker makes the underseats sound better. THis has been observed also with Rainbow Sound Line 210.25 comps in a HiFI car (mine, before a road trip last year).

[Lee Rambler]

the gains on the underseats needed adjusted down after the quart install, the oem L7 drivers are substantially more efficient (combined with being 2 ohm...) and made the underseats way too loud by comparison. Still doesn't make them any cleaner though =(. Not terrible by any means, and not sure what I'm going to find to replace them... may try those morels, don't know that there are any other good options that will fit...

[Lee Rambler]

fyi for anyone who does it, the underseat subs (if kept stock) end up being out of phase with the quarts. spent quite some time today tuning everything after finishing the rear speaker install and I'm pretty please with the overall results. Could use some more power, but think I'll keep it as is until the new JL XD amps ship. After tuning, the oem underseat woofers aren't too bad. May still upgrade them, will give it a week or two to see how things sound once fully broken in.

[kaigoss69]

Originally Posted by Lee Rambler

fyi for anyone who does it, the underseat subs (if kept stock) end up being out of phase with the quarts. spent quite some time today tuning everything after finishing the rear speaker install and I'm pretty please with the overall results. Could use some more power, but think I'll keep it as is until the new JL XD amps ship. After tuning, the oem underseat woofers aren't too bad. May still upgrade them, will give it a week or two to see how things sound once fully broken in.

Thanks for the tip, I'll flip the phase on my Earthquakes to see if that does anything. If not, I have some old Morel CW8s waiting to see juice for the first time!

[Dackz]

Originally Posted by Lee Rambler

fyi for anyone who does it, the underseat subs (if kept stock) end up being out of phase with the quarts. spent quite some time today tuning everything after finishing the rear speaker install and I'm pretty please with the overall results. Could use some more power, but think I'll keep it as is until the new JL XD amps ship. After tuning, the oem underseat woofers aren't too bad. May still upgrade them, will give it a week or two to see how things sound once fully broken in.

They are in phase with the front OEM drivers though correct?

[VP Electricity]

This conversation is starting to miss the differences between phase and polarity.

Phase is a function of time, and since sound travels relatively slowly, it becomes a function of differing distances as well.

Polarity is how the speaker is wired. If the speaker is wired to move OUT with a positive pulse, it is often considered to be out of phase with another speaker wired to move IN with a positive pulse.

But when speakers are different distances from the listener's ear, phase becomes much more of a crap shoot.

t's hard to model (believe me, some people really try) but whenever you have a multi-way speaker system, and you want it to sound as good as it can, you really need to listen to each set of drivers connected in each polarity relative to the others.

The question shouldn't be, are the speakers wired identically in the door and in the underseat and in the rear deck? This is not a valuable thing to know. Thee valuable thing to know is, which way sounds best? This needs to be determined empirically.

If you go with different (upgraded) speakers and new amps and new passive or active crossovers, you need to re-test and not assume someone else's results are correct. Passive xovers often invert absolute polarity AND they insert additional phase shift (think of phase shift as a frequency-dependent delay). Active crossovers (except for well-executed DSP filters) do the same thing.

So the best thing to do is to listen to it...

[Dackz]

Originally Posted by VP Electricity

This conversation is starting to miss the differences between phase and polarity.

Phase is a function of time, and since sound travels relatively slowly, it becomes a function of differing distances as well.

Polarity is how the speaker is wired. If the speaker is wired to move OUT with a positive pulse, it is often considered to be out of phase with another speaker wired to move IN with a positive pulse.

But when speakers are different distances from the listener's ear, phase becomes much more of a crap shoot.

t's hard to model (believe me, some people really try) but whenever you have a multi-way speaker system, and you want it to sound as good as it can, you really need to listen to each set of drivers connected in each polarity relative to the others.

The question shouldn't be, are the speakers wired identically in the door and in the underseat and in the rear deck? This is not a valuable thing to know. Thee valuable thing to know is, which way sounds best? This needs to be determined empirically.

If you go with different (upgraded) speakers and new amps and new passive or active crossovers, you need to re-test and not assume someone else's results are correct. Passive xovers often invert absolute polarity AND they insert additional phase shift (think of phase shift as a frequency-dependent delay). Active crossovers (except for well-executed DSP filters) do the same thing.

So the best thing to do is to listen to it...

Or add a bit one and do it all right I suppose, LOL.

[VP Electricity]

Originally Posted by Dackz

Or add a bit one and do it all right I suppose, LOL.

Still should do this even when using a bitone. Fortunately, the b1 and the Zapco DC software make it as easy to swap polarity as clicking a mouse

The new JBL MS-8 MIGHT do the adjustment automatically, as the Alpine 650/660 might as well. But I hate automatic tuning

[Lee Rambler]

Originally Posted by kaigoss69

Thanks for the tip, I'll flip the phase on my Earthquakes to see if that does anything. If not, I have some old Morel CW8s waiting to see juice for the first time!

not sure it will be the same with the earthquakes, or the morels - you'll have to try it with each.

agreed 100% with VP that you need to try it. Also agreed 100% on not liking automatic setups. personally think it's best to have the absolute best starting point before any "automatic" adjustments or eq or any sort is done.

merely semantics, but phase is not necessarily distance related (distance can certainly have effect on it though). Polarity is a fixed 180 degree phase (ie high and low). Phase can be any relation of a sine wave's position. A fairly basic example is 2 phase AC electric vs 3 phase AC electric. In the audio field, polarity typically refers to the absolute phase of drivers, ie moving in vs moving out. Phase usually is related to distance of drivers apart, since once you have the absolute phase correct, this is the thing that will affect it. But that's not to say that phase only relates to distance, as other electrical components can affect it - ie a capacitor or inductor (in a crossover)...