http://www.hometheaterforum.com/htforum/showthread.php?s=&threadid=182402&highlight=tumult
My sincere apologies. I got the names mixed up.
My sincere apologies. I got the names mixed up.
david funke said:
David
You can read more about the Linkwitz Transform here:
http://sound.westhost.com/linkwitz-transform.htm
This was linked in another thread and I found it quite informative. That same website has a project for a LT, but you would have to put it together yourself. You have to design to fit your needs.
Maybe someone else knows of a place you can purchase them pre-made.
Hi,david funke said:
If you're using your LFE channel, then it should probably be forward firing, as frequencies above about 50hz (many say 80hz) are directional, and may sound wrong coming from a downward firing sub. Excursion loss is insignificant for a monster driver like this I would think. The upside of downward firing is the 'coupling' with the floor, which gives extra output.
I really am no expert, but I suspect the smaller box (sealed) will help sound quality, as it's impossible to practically make a large box inert, and it may resonate at too low a frequency, and store more energy. I feel my 250l Tempest box shaking around a lot at very high levels, a bit of bracing won't stop it. I think my cabinet muddies the sound
I believe musicality comes almost solely from good integration with the main speakers, ie. correcrt phase setting, x-over slope and frequency, level, and position in the room. I think!
With respect, I think you're generalising and simplifying too much.454Casull said:
Some people use their subs under their main speakers' natural roll-off ie. hi-fi style. Many people use them to play the LFE channel from their home cinema processor/receiver, which won't likely be crossed over low enough to be totally non-directional. IIRC for some standard or other the x-over is 80hz, and as some frequencies above this will be heard, you will be able to localise the sub, so positioning *may* be important. I can hear where my sub is, and that comes in at 50hz (ok, it's right next to me, but still!)
The larger the box is the better it sounds: I don't see the logic there. The bigger it is the tighter the bass will be and it will just seem quiet with normal ported main speakers, and lose power handling. Bigger looks bad and has more box to vibrate, as I already said. I've never heard a true IB sub, but if I stuff my ports the sub is harder to integrate and sounds boring, might aswell not be there really. It's all trade-offs at the end of the day
Im gonna be the minority here and i'm probably going to be flamed but I must speak, so take it for what its worth. I did not have a good experience with the Tumult. I bought one and wound up selling it. I simply could not get it to integrate with ANY of my systems (car audio, home audio or even my PA DJ system). I used many different amps, from a weak 60 watt x 4 Adcom, to my largest PA amp a Crown MacroTech MA5000VZ (2500 wattsx2 continuous, 2 ohms.) I also experimented with different enclosures, from Sonotube designs to box designs, both ported and sealed, from WinISD calculations as well as some of the ones on their site.
Anyway, I find some of its specs questionable. 34 mm one way excursion my eye. If that were so, the driver should be able to move in and out almost 3 inches. To hit 34 mm one way, you'd have to push 3500+ watts into the thing, in free air. With its power handling specs and low sensitivity thats just not gonna happen. You'd wind up toasting the voice coils before it ever got that far. I'd say the realistic excursion was maybe 3/4" before I started hearing the golf balls hitting concrete sound (and this was with only ONE of the macro-tech's channels running into a 4 ohm load).
Its 87 dB is definately a short coming. As for low distortion, well yah even if you're driving 1000+ watts into the thing and all thats being turned into heat and driving up your electric bill, if the woofer is barely putting out any power of course the distortion is gonna be very low.
If you use 2 or even 4 of them with a ton of power, then yes I think you could move some air. Honestly I expected more. For the price, there are better chioces IMHO.
Anyway, I find some of its specs questionable. 34 mm one way excursion my eye. If that were so, the driver should be able to move in and out almost 3 inches. To hit 34 mm one way, you'd have to push 3500+ watts into the thing, in free air. With its power handling specs and low sensitivity thats just not gonna happen. You'd wind up toasting the voice coils before it ever got that far. I'd say the realistic excursion was maybe 3/4" before I started hearing the golf balls hitting concrete sound (and this was with only ONE of the macro-tech's channels running into a 4 ohm load).
Its 87 dB is definately a short coming. As for low distortion, well yah even if you're driving 1000+ watts into the thing and all thats being turned into heat and driving up your electric bill, if the woofer is barely putting out any power of course the distortion is gonna be very low.
If you use 2 or even 4 of them with a ton of power, then yes I think you could move some air. Honestly I expected more. For the price, there are better chioces IMHO.
tg3 said:
16 cubic feet? That's a 32" cube.
It's a plinth that my sofa sits on, 4ft deep 15inches high and about 7ft wide, there's a divider in the middle and the subs sit in the left hand side, I originally planned to house 4 Tempests in it, 2 on each side but only got around to doing the left hand side which is more than enough, especially with Tumults instead of Tempests.
I'm not sure why ericdwong got the results he did from his Tumult, I'm most puzzled about his Xmax comments. I've used a few Brahma 15's in the past (I think that would be a decent comparison) I had one in a 6ft box @ 20Hz. I measured the xmax by using two small lasers I have (lining them up with the farthest most inward cone movement, and then the outermost, pull the box away and measure the same two points with a ruler) I had about 45-47mm between the two beams with 750WRMS (27 Hz Sine wave). That would be pretty close to full xmax at 750 watts. It was also quite loud. I'm not sure if you can buy a better sub as far as output and Distortion than the Tumult. All The Brahmas I worked with sounded great. I will goof with the lasers on my Tumults when I get the boxes done.
DanWiggins said:
Hello Dan, I have a pair of DPL12's and have one of them in a 3 cu ft cabinet. The cabinet is about 30% poly filled and I am driving the speaker with a 150 ILP bipolar map module. The voice coils are paralelled and I am running thme from an 80 HZ preamp output. My problem is I have to adjust the preamp output to -10dB to stop the DPL12 from clapping, what could I be doing wrong? An open ended question I admit but I thought I would be able to pump through significantly more power before I started bottoming the voice coil. The cabinet is a selaed downward firing enclousure from CSS.
Any Ideas?
Regards
Anthony
I'm not familiar with that amp - any EQ, boosts, or other things in it? Also, just because the gain is set to -10 dB doesn't mean you're not pushing the amp all the way. What's the sensitivity of the amp, and what's the level of the signal?
One thing to consider - if you can bottom it with less power than anticipated, that's usually considered a good thing. Especially with a sealed box. The output of the sub is 100% dependent upon the displacement of the driver. Once you reach the bottom, you're at full output. If that happens with 100W rather than 1000W most people are happy...
Does it sound loud and clean up to the point of bottoming? If so, then back off the gain a hair and don't fret about it. If not, you might want to consider porting the sub to get more output down low.
Dan Wiggins
Adire Audio
One thing to consider - if you can bottom it with less power than anticipated, that's usually considered a good thing. Especially with a sealed box. The output of the sub is 100% dependent upon the displacement of the driver. Once you reach the bottom, you're at full output. If that happens with 100W rather than 1000W most people are happy...
Does it sound loud and clean up to the point of bottoming? If so, then back off the gain a hair and don't fret about it. If not, you might want to consider porting the sub to get more output down low.
Dan Wiggins
Adire Audio
kan3 said:
That is a very good point. If you look at the xbl^2 white paper, you will see what happens to efficiency with excursion. On drivers with parabolic curves, the efficiency starts to drop off once the driver moves. But the flat BL curve of XBL^2, the although slightly lower efficiency at rest stays the same throughout 70% of it's linear throw. This means that at certain frequencies/output levels the XBL^2 driver can actually have higher efficiency. That is the BL compression kan3 mentions above.
95Honda said:
I'm not surprised at ericdwong's results. Not everyone likes the sound of the XBL^2 motor. Some people are used to the higher distortion levels, and with that missing, it doesn't sound right to them. There is nothing wrong with it. Although I do find it unfortunate that the driver gets discredited due to a subjective observation. That's why sometimes I think knowing the design is much more helpful than listening to a strangers impression of a driver.
Although I for one LOVE the sound of my Brahma as well. I can't wait till I get a chance to hear a Tumult, or even better yet the Parthanon.
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