I have been looking at that sb acoustics driver, but it's a bit low on efficiency.. Looks like that is the compromise, though... Frequency vs efficiency. Or spending more $$$ and getting more of both.
I've spent the morning reading up on xovers and am warming up to the idea of higher orders... not sure yet..
I've spent the morning reading up on xovers and am warming up to the idea of higher orders... not sure yet..
I don't think you need more than 91db to match the 86.5db of the FF85wk.
In fact the SB woofer according to the FR diagram here (click on the picture and scroll to the third image) reaches approximately 93db in the frequency range you want to use it (<300Hz) and the Fostex is at around 88db above 300Hz.
In fact the SB woofer according to the FR diagram here (click on the picture and scroll to the third image) reaches approximately 93db in the frequency range you want to use it (<300Hz) and the Fostex is at around 88db above 300Hz.
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I've got the older 85k (not wk) which is 89db, if I remember correctly.
Thanks for the link to the datasheet.. It doesn't look bad for my application.
actually, I just looked up the datasheet for the 85k vs the 85wk, and they're about the same on most frequencies... my 85k has a loud high end, which is where the extra efficiency numbers come in.
Thanks for the link to the datasheet.. It doesn't look bad for my application.
actually, I just looked up the datasheet for the 85k vs the 85wk, and they're about the same on most frequencies... my 85k has a loud high end, which is where the extra efficiency numbers come in.
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Planet 10 (or anyone w/ Acoustic Elegance experience), if I were to go all out and get those drivers, would you still go for a low crossover point, or maybe raise it to take advantage of the good mid-bass of the AE drivers? I think I'd still want to keep it relatively low, but maybe up to 600 or 800hz.
Or, is that a bad xover point, since there's usually a lot going on in those frequencies? Maybe there's no good xover point,so I shouldn't worry about that
.
Or, is that a bad xover point, since there's usually a lot going on in those frequencies? Maybe there's no good xover point,so I shouldn't worry about that
.
Maybe there's no good xover point,so I shouldn't worry about that
The AE drivers (amongst the best available) do have good extension on the top, giving you lots of flexibility, personally i like to keep it near the bottom of the critical band, and where the impedances reach their minimum.
The width of the box (ie where bafflestep occurs), limits the ideal XO location if you are using just differing sensitivity to gain BSC... somewhere on the order of sqrt(2)/2 to 1 times 4560/baffle width in inches is the ballpark.
dave
Oh man. Sorry, but I kinda think using a nice AE driver is a bit of a waste in this application. Crossing low isn't what makes the AE woofers so great. If I had the money for an AE woofer I'd team it up with a nice horn and cross around 1000hz. Those are really nice drivers. With a FAST, all that useful extention gets buried. Yes, you need extention to make a shallow cross over, but it doesn't have to be nearly that good. Also, the AE woofers give up a bit of bass (still quite good) for sensitivity and extention.
I modeled a bunch of drivers in my boxes last night, and it doesn't look good!
The SB Acoustics one has a big bump on the low end. Plus I noticed their efficiency rating isn't db/W, it's DB/2.83v which is probably around 88db/w, so too low. The Acoustic Elegance speakers appear to be lacking bass. They show up as -2db all the way up at 100hz!
The Eminenance is even worse on the low end.
The Fostex, however was a flat line, gently curving and down -3db at 50hz. It was definitely the best of the 10 or 15 drivers I modeled last night.
I guess that brings the question... Can speaker modeling programs really be trusted? The models make the Acoustic Elegance spekaers look to be about the same as the Eminenance, and the Fostex look like the king of deep woofer drivers.. which from reading around on the net, it does not appear to be....
The SB Acoustics one has a big bump on the low end. Plus I noticed their efficiency rating isn't db/W, it's DB/2.83v which is probably around 88db/w, so too low. The Acoustic Elegance speakers appear to be lacking bass. They show up as -2db all the way up at 100hz!
The Eminenance is even worse on the low end.
The Fostex, however was a flat line, gently curving and down -3db at 50hz. It was definitely the best of the 10 or 15 drivers I modeled last night.
I guess that brings the question... Can speaker modeling programs really be trusted? The models make the Acoustic Elegance spekaers look to be about the same as the Eminenance, and the Fostex look like the king of deep woofer drivers.. which from reading around on the net, it does not appear to be....
yes, but you need to learn how to 'fiddle' with the calculation
try to lower Box Q you can get low bass in closed box with a higher Qts driver, but generally low Fs will be the better main player
if you get a 'hump' like you say, your box is too small
when the box size is given you have a few other options
either use a driver with slightly lower Qts
or a driver with lower Vas
or both
I would suggest to aim for a nice looking gradual rolloff, round and smooth
for this small fullrange a well defined bass is likely to work best
with a very pronounced low end there will be risk of drowning it completely
The Acoustic Elegance drivers are quite good - at least I can speak on behalf of the TD15M. My 5ft^3 box tuned to 32Hz might seem to lack bass in simulation, due to an early, but very gradual roll-off, but this happens to complement my room very well. Speakers that are truly flat well into the bass can oftentimes be a bit much for certain rooms. Since you seem to be designing from scratch, tailoring that response to your taste is quite fortunately an option.
Another thing to keep in mind appart from a plain simulated transfer function, is that bass from a 12" or 15" woofer won't sound the same ast that from a 6" or 8", even for a comparable response. The larger drivers sound effortless and have greater radiating efficiency, handle loud transients better; they just sound more life-like to me. Still, a good 8" might be quite adept at doing a great job under FF85WK, which is not a high-power pro driver itself. I would personally consider the Peerless HDS Nomex-cone 6" or 8" for this job. I'm a bit at a loss for recommending a 12" that won't blow the budget though. I certainly would not spend 600$ on a pair of TD12M for 40Hz-300Hz duty.
IG
Another thing to keep in mind appart from a plain simulated transfer function, is that bass from a 12" or 15" woofer won't sound the same ast that from a 6" or 8", even for a comparable response. The larger drivers sound effortless and have greater radiating efficiency, handle loud transients better; they just sound more life-like to me. Still, a good 8" might be quite adept at doing a great job under FF85WK, which is not a high-power pro driver itself.
I would personally consider the Peerless HDS Nomex-cone 6" or 8" for this job. I'm a bit at a loss for recommending a 12" that won't blow the budget though. I certainly would not spend 600$ on a pair of TD12M for 40Hz-300Hz duty.IG
Flame suit on, as I am about to commit what a lot of people consider to be sacrilege, but how about crossing over actively using a DSP and bi-amping the speakers?
The main advantage is that the choice of potential woofers will much bigger as you won't have to match its sensitivity to the FR driver's and use a relatively cheap high power class-D amp to drive the woofers.
Furthermore, good DSP's (like the mini-DSP) can be had for a fraction of what you might pay for decent passive crossover parts, and with an unlimited choice of crossover points allowing you infinite crossover frequencies and slopes.
Just a thought.
Nick
The main advantage is that the choice of potential woofers will much bigger as you won't have to match its sensitivity to the FR driver's and use a relatively cheap high power class-D amp to drive the woofers.
Furthermore, good DSP's (like the mini-DSP) can be had for a fraction of what you might pay for decent passive crossover parts, and with an unlimited choice of crossover points allowing you infinite crossover frequencies and slopes.
Just a thought.
Nick
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Excellent way to go IMO, for all the reasons you mentionned and more. I'm using a MiniDSP on my large two-way pro driver setup, AE TD15M and BMS 4550 on QSC waveguide, I love it. It's possibly even a very lazy solution in my case, as my drivers and Xo point should not be hard to design passively for.
When dealing with crossover points pretty close to both driver's Fs, as is the very case in a fullrange + woofer (FAST), you can save a whole lot of potential trouble by going active.IG
Well, good thing you wore that flame suit, because.... hehe, just kidding..
But, no...... I'm not ready to go back to the dark side.. I switched to all tubes about 10 years ago, and haven't looked back.. I just finished my first tube amp that gets in to the double digits, (triple, even.. Ideally, I can get almost 100 watts out of it).
I don't know at this point.. I'd still have my all analog, all tube, phono to speaker system upstairs.... But, for this project for now, I'm sticking to tubes. Some day maybe I'll try that DSP. If people here recommend it, it must not add much to the sound.. But, how can it not add something?
I got a pair of cheap $40.00 woofers from MCM (12" die-cast).. It modeled surprisingly well, and get's relatively low. These will get me started until I have time to properly research speakers. If anyone wants to keep giving advice, I'm still looking for it.. But, will pop these woofers in and listen to my new amp and take some time w/ my research
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I have went thrue the same task two month ago. I settled with the beyma 12br70. Their is not a lot of 12 inch that can go in the low 30's. The kappa pro was another contender, but thats about it. the AE was out of my price range.
just make sure that the driver you choose can go low enough for your needs
just make sure that the driver you choose can go low enough for your needs
Well, good thing you wore that flame suit, because.... hehe, just kidding..
But, no...... I'm not ready to go back to the dark side.. I switched to all tubes about 10 years ago, and haven't looked back.. I just finished my first tube amp that gets in to the double digits, (triple, even.. Ideally, I can get almost 100 watts out of it).
I don't know at this point.. I'd still have my all analog, all tube, phono to speaker system upstairs.... But, for this project for now, I'm sticking to tubes. Some day maybe I'll try that DSP. If people here recommend it, it must not add much to the sound.. But, how can it not add something?
I got a pair of cheap $40.00 woofers from MCM (12" die-cast).. It modeled surprisingly well, and get's relatively low. These will get me started until I have time to properly research speakers. If anyone wants to keep giving advice, I'm still looking for it.. But, will pop these woofers in and listen to my new amp and take some time w/ my research
Well both approaches need not be mutually exclusive.
In my OB setup, I am using a flea watt EL34 SET amp (3 watts/channel) on my full range drivers (FF125WK's) and a very good sounding Class-D amp from class-D audio to drive the woofers. I like to think of it as the best of both worlds, or at least that's how it sounds to me.
The miniDSP actually adds very little to the sound, little enough not to be worth mentioning for most listening except the most critical.
Anyway, it's getting really hot under that heavy flame suit, so I guess I'm gonna take it off now and watch passively at how your projects evolves
Enjoy the ride
Nick
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