Impious

If your current sub is wired to 2ohm, then it's not getting 1800w, it would be receiving half of that. And yes, if you wire two subs of the same impedance together they will each receive half of the power.

Hard to tell from the picture, but to me it looks like this driver also uses the two-part top plate. I'd gander a guess that even it if was designed similar to the original, it probably uses the same newer assembly/construction method as all of the other XBL drivers. I don't know of any XBL driver currently being produced that doesn't use that style of motor assembly.

Yes, you would need a DMM to set the SSF with any kind of accuracy.

How you are setting the SSF to specific frequencies? Two explanations for the difference in output at >30hz with the SSF set below that. First, an SSF is nothing more than a highpass filter. The crossover point for the SSF is the -3db point for the filter. So even though it is set to 25hz, it is going to begin attenuating frequencies well above 25hz. Second, depending on how you are setting the SSF, you might not be setting it as accurately as you think. As far as what is "safe". There's no real answer. It depends on how much power you are running and the excursion levels of your driver in the enclosure. This can be predicted with any enclosure modeling program. Generally there is going to be *some* frequency range below tuning that the drivers excursion will remain with it's linear limits, and then a wider frequency range below tuning that the driver will stay within it's mechanical limits. But where those ranges fall is dependent upon your power level and enclosure.

Another issue could be that the amplifier is clipping and/or if the passive crossovers have built-in tweeter protection, you could be triggering the tweeter protection. Amplifier clipping in the treble will subjectively sound like a dulling of the sound. And tweeter protection will reduce the power to the tweeter, which will affect it's output relative to the mid. I would check the line driver (the box connected to the factory speaker wires) to see if it has a gain control and see where that is set, then also check to see where the amplifier's gain is set.

You need to at minimum state a budget.

You are certainly entitled to your opinion, so I'm not "arguing" per say, just offering a different point of view. (I like to play devils advocate) If you try to optimize the stereo for both seats in an automobile, you are necessarily going to have to make sacrifices to the sound for both seats as well. It's a trade-off, you can't have the best of both worlds. You can't optimize performance at both listening positions. On the other hand, if you optimize for a single seat you can reduce the number of sacrifices you are going to have to make to the sound at that one listening position. Sure, one of the trade-offs is that it sounds like monkey butt from the passenger seat.....but if that means better sound in the drivers seat, where most of us involved in car audio sit....than many consider that a beneficial trade-off. Good sound in two seats, or better sound in one seat.

There is a measurable difference in 500w of power at any level. Just because something is measurable doesn't mean it's audible, and if it is measurable and audible you still didn't isolate the reasons for the difference. So the termlab results are pretty meaningless And a 500w power difference doesn't mean anything either. I'd surely bet you could hear a difference in a 500w power difference if we start with a power level of 500w, for example. So that's a pretty meaningless example as well. And of course you can exchange amplifiers close in power rating and hear a difference. Hell, you can exchange amplifiers rated for the same power and hear a difference. You can exchange two identical amplifiers and hear a difference. That doesn't mean there was an audible difference in the amplifiers, but rather in the settings. These are two different things completely and should not be confused.

Listening to the system "a lot" really has nothing to do with it. There are limits to the threshold of human hearing. I'll bet the numbers go up as well, as there is certainly a measurable difference in 300w of power. A noticeably audible difference due to 300w difference in power is less likely, although changes in all of the variables involved certainly allows for there to be a change in sound when exchanging amplifiers.

No one can tell you that you didn't hear a difference. But we can tell you that you didn't hear a difference for the reasons you probably think you did. Differences in gain setting and structure, crossover points, and a dozen other variables will all cause an audible change in sound. That doesn't mean you heard a difference because of a ~300w change in power.

For measuring T/A ? You'd need a microphone, and microphone preamp, a sound card (with fixed time latency), and an MLS software program. MLS software generates the test signal then takes the measurement of that signal via the microphone, which allows it to provide impulse response measurements. Fixed latency is important in the sound card because if there is a variance in the time it takes for the soundcard to generate the sound then begin measuring, the impulse response will be different every time you measure. To solve some issues, some people (like myself) go with a single external unit that is both a good quality soundcard and a mic preamp. I just got my PC based measurement system working tonight......like, an hour ago (issues with my M-audio driver). I have a Dayton EMM-6 microphone, M-Audio MobilePre external soundcard/mic preamp, and am planning to use HOLMImpulse for my measurement software. Hopefully this weekend I'll get to play with it some. For one, in order to T/A individual drivers, each driver would need to be on it's own channel both at the processor/HU and at the amplifier, and each channel has to have a time delay adjustment. He more than likely doesn't have this capability as he would need 12 individual channels (both preamp and amplifier) just for his front stage. Really though, T/A for tweeters is a finicky thing. For one, we don't localize sound in that frequency range by time arrival, we do it by inter-aural intensity differences. So delta (left-right) time alignment itself won't serve much benefit on tweeters. One benefit that T/A can have for tweeters is that it will also basically serve as a phase adjustment (delaying one signal will affect the relative phase with the drivers as well), which can help fix some frequency response issues around the crossover point if the tweeters and mids are at different distances from the listener. To do this we would use parallel time alignment to "time align" (although in this case it's more about phase than actual "time") two different drivers on the same channel (left or right).

I won't touch on the center of the vehicle thing for delta time alignment as Adrian already hit the nail on the head. I'm pretty sure they all do output sound at the exact same instant as the others, unless he is using miles of speaker wire or has already applied time delay. Now when that sound arrives at the listening position, that's more important. You still wouldn't want to measure to a center point in the vehicle to determine parallel time alignment, as the distance between speakers on the same channel is going to depend on the speaker placement and measurement axis. And for delta time alignment, as already covered, you absolutely must measure at the listening position. I do not believe he has control of time alignment for each individual driver. So parallel time alignment is a moot point anyways.

How would that help? If the speakers are located at the same locations in the vehicle (i.e. doors), and you measured to a point in the center of the vehicle.....the speakers would measure equidistant You would have to measure the differences at the listening position. Then again, I've never set time alignment with measurements.....I've always set it by ear.

In that case, IMO easiest thing to do is wire them up temporarily through the passive with the mid/tweeter roughly where you want them either velcro'd in place or propped up with a towel or something and listen to them. Then switch it over to active, run the dome without a lowpass and listen again and see what you think. Obviously it won't be perfect as the dome was probably not designed to be a true full range driver......but it will give you a quick-n-dirty difference. See what you think. If it doesn't sound awful to you without the tweeter, then you should be good to proceed with finding a suitable full range driver. Or PE has a Tymphany 2" full range driver for $9. So for $20 you could try it out compared to the 3-way just to see what you think of the differences. http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=299-249&ctab=1#Tabs

http://stereointegrity.com/Files/RDOOperation.pdf

Do you have the Bravox Aaron?

YAY! You can hide it now!

Certainly they aren't the end-all objective measurement that completely defines a loudspeaker, no one has said they are. But they do absolutely allow you to ascertain certain aspects of the performance of a loudspeaker, much more useful than simply determining enclosure size. Really, the purpose of T/S parameters isn't at all to allow you to design an enclosure, as you suggested. They provide an objective description of the low frequency response characteristics of the driver (as well as some high frequency information), which in turn allows us to accurately predict how the driver will respond in a given enclosure in terms of frequency response, phase response, transient response, etc (among other things). Sure, people can use them to design an enclosure. But that's because of how useful T/S parameters are. They allow us to predict this information. But the actual intent of T/S parameters is to objectively describe the low frequency behavior/response of the loudspeaker, which has the good fortune of allowing us to make accurate predictions. Which are then useful for other things, such as enclosure design (for one example) Certainly someone should design their system for their own enjoyment, whatever that may be. No one can argue against that point. But don't think it's not possible to criticize a loudspeaker without hearing one if sufficient objective data is available. As Sean has pointed out; a loudspeaker can't do anything that defies the laws of physics. The pertinent aspects of it's performance can be obtained from proper objective measurements. Why is it that this entire discussion is being taken as "stepping on toes"? No one in this thread has made one discouraging remark against the drivers performance, yet many of the Blues supporters seem to be getting defensive over it. The only comments I've made directly about the speakers are 1) the drivers are expensive (self-evident from their listed prices), and 2) none of the information provided tells us anything about their actual performance (self-evident from the [lack of] information provided). Who's toes is that stepping on?

I've not read the link (hell, I didn't even know that forum existed), but just a couple quick off-the-top things to think about. First, you are probably going to lose top end by going with a single 2-3" full range driver......most of them either start to roll off at ~10khz or have rough top end response. And a lot of them don't have great distortion performance over that large of a bandwidth. Second, aiming is going to be more picky and critical as they are all going to experience beaming well within their bandwidth.....a 2" cone is going to start beaming 6750hz, a 3" driver obviously sooner. Seems like there's more I was going to mention, but drawing a blank after I started typing Long day.....

There's a blast from the past. It'll be interesting to see what all Scott has up his sleeve for this new brand.

You mean subjective. I watch for the commercials (well, used to.....they've sucked here the past few years) I think you mean subjective again. Some car stereos get "rated" or judged at car audio competitions. But we aren't discussing car stereos as a whole, we were discussing an individual product; speakers. Therein lies the problem. A car stereo competition is a terrible means by which to attempt to "judge" individual speakers against other individual speakers. It's subject to a wide range of variables.....from subjective opinions to environmental and tuning/setup issues. Which makes it pretty useless for the purposes of comparing speakers themselves. Enter objective measurements......the ideal grounds upon which to compare individual speakers. Do those even exist anymore? Huh? If you don't understand how objective measurements correlate to the "real world", then you don't understand objective measurements. If you think that's the extent of the usefulness of T/S parameters, then you don't understand T/S parameters. 30% is a pretty pessimistic figure, or a brand with lesser quality QC......most good brands with decent QC are going to be in the sub-20% range. Which realistically isn't going to make much of a difference in overall performance. It would certainly be naive to think (or say) that T/S parameters entirely encapsulate the sound of a speaker. Nobody here is making such a claim. T/S parameters are a good start to understanding the behavior of a speaker, however. And some trophies and subjective opinions certainly don't tell me anything about the speakers. Though I do agree, one should select products based on what sound the end user is looking to achieve. But that doesn't make objective measurements any less useful.

My previous RCA's were something like $4.99 from partsexpress, and my current RCA's are Radio Shack specials. You do not need to spend a lot of money on RCA's. Switching RCA's and experiencing a difference isn't conclusive proof that RCA X is better than RCA Y without being able to identify exactly what caused the issue. Variation in the routing of the wire run through the vehicle alone could cause difference. On top of that, some would make an argument that shielding isn't necessary in RCA's. That's one of the long standing disputes (UTP vs. shielded RCA's).

I would highly recommend the products from SDS: www.sounddeadenershowdown.com

The other problem I forgot to mention about ordering something in singles even if the company will supply just one. Price.

Pretty sure there's a noise trouble shooting guide sticky'd here. I know because I put it there Have you checked that?