DIRECT drop in replacement of the tumult in a sealed tempest enclosure *pics* (1 Viewer)

[Anthony_Gomez]

Below is an image that may interest some of you.
Lets make a few things clear.
1)These volumes are NOT ideal for the tumult, but are for the Tempest. A BFD or LT can easily adjust your Q to taste.
2) These are unibox simulations. No leaks and No fill were selected to best approximate the Q and Vb listed on adire.
3) At 250 watts, the tempest is just at the linear excursion limit right till around 15hz where it just slightly crosses
4) The tumult is linear in ALL graphs from 10hz on up, except for 1250 watts where it exceeds linear xmax at about 15hz.
I will have plots of the 230L (tempest Q=0.557) and the 65L (tempest Q=0.9) that adire lists later on. I have class soon and couldn't finisht them in time for this post.
IF ANYONE WANTS TO SEE ANY OTHER PLOTS....let me know the specifics and I can generate them. I figured that this would be the most interesting. The equivalent ported comparison isn't because the Tumult really wants PR's IMO...and with most tempests in a sonotube, this just isn't going to happen (as a drop in replacement)
Enjoy!
Link Removed

 

[Kyle Richardson]

Looks great. Very interesting for those that want to drop a Tumult into their current Tempest sealed enclosure.

If you get time later post a graph with the Tumult and Tempest in their respective boxes at a q=0.707 with max power applied to both that keeps both within their linear xmax range. That should be interesting too, although it wont help those that want to drop a Tumult into an existing enclosure.

 

[Anthony_Gomez]

Here is another one for your notes.
Here, everything is linear for the tumult, and the tempest is at its linear limit below 20hz (xmax is almost a flat line below 20hz right on the linear limit).
I included a 0.1ohm series resistance whish is pretty typical.

 

[Gomer]

Dude, pretty nice graphs! It is about time you contribute something useful in this forum!

 

[Anthony_Gomez]

Who the hell do you think you are Gomer? ALL of my posts are completely on topic and are EXTREMELY usefull.

 

[Kyle Richardson]

At least you entertain yourself
Hey, in the second graph, is the Tumult 42.6L/680w & the Tempest 119.2L/250w overlapping each other? Thats pretty cool. That more than anything shows the differences between the two drivers (at least on paper). Tumult=small box more power/Tempest=larger box smaller power. Pick your combination you like best and get ready to rumble. That red line on top really shows the differences as well. Throw some power to that bad boy and make sure you are sitting down before it knocks you down

 

[Anthony_Gomez]

Yup. They are overlapping indeed! ....if power isn't a concern, this sure shows how SAF can be tamed!

 

[Manuel Delaflor]

The overlapping is indeed interesting. Of course it is desirable to have such a small enclosure. Still, when the space nor the WAF are problems, the Tempest is still an extremely good competitor (to its excursion limits of course).

 

[Jack Gilvey]

Good illustrations, shows that Tumult seems to have achieved our collective design goals nicely.
Remember that, while the Tumult has the Vd of approximately two Tempests, XBL2 keeps it more linear as each reaches its limits, leading to Dan's estimation that it'd be equal to almost three Tempests if a 10% THD limit is imposed.

 

[Dan Pawlowski]

Anthony
Your graphs are off slightly for your comparison of Tempest and Tumult using a standard 250W amp.
If I could get the export GIF to work on Unibox4.01, I would show you. But here is why:
The AVA250 amplifier with an applied load has an output
voltage of about 28V rms (I measured mine) and a current limit rating of 15 Amps rms (the value for current is chosen as to be safe not to fry the output transistors). Which means the amp is capable of delivering IMO up to 420 Watts of reliable power depending on the load. Since the Tempest VCs in parallel are 3.5 ohms the max power before the amp clipping would be 225 Watts. For the Tumult the VCs in series is supposedly 2.6 ohms which would yield 300 Watts. It gets tricky if you use one VC on the Tumult at one 1.3 ohms, 600 Watts not recommended at all IMO (600W would draw 21 amps and the transistors are rated for 20). So what am I rambling on about??
In the UNIBOX spreadsheet under nominal power for the Tumult the value entered should be 300 Watts and for the Tempest should be 225. The key is to keep the applied voltage the same for whatever speaker you are testing if you use the same amplifier.
The difference it makes in your graphs is about 1.25 dB. The Tumult should be increased by 1.25dB, not much but hey I am just trying to be accurate.
Dan

 

[Rick Chwiendacz]

Sorry to interject here, but I feel obliged to clarify a few things:

First off - the rail voltages on the AVA250 should be much higher than 28V each. If they were indeed +/28V, (note that the power supply rails should be DC, or very close to it, so there's no need to specify RMS here) the amplifier would only be capable of about 98W into 8 ohms or 196W into 4 ohms, assuming no extra I^2R losses in the amp.

If I remember correctly, the amplifier uses much higher rail voltages than that - in fact, I believe it uses 80VDC filter caps for each rail, now that I think about it.

It should also be noted that the output transistors in the amp (2x 2sc5200 and 2x 2sa1943, IIRC), aren't rated for anywhere near 400W - Toshiba (the manufacturer) rates them for 100W/pair, so 200W total for the amp. The current rating on the transistors is also almost meaningless when it comes to audio - the power dissipation ratings and second breakdown curves are of much greater concern - all the amperage ratings really tell you is how thick the wires are connecting the die to the package.

At any rate - don't assume that you're going to get more than 300W reliably out of the AVA250 - it may give you more for a short time, but you're tempting fate if you ask it for any more than that.

This isn't meant to be a slight against the AVA250 either - it's quite a capable amp for a respectable price, but there's only so much power you can squeeze reliably out of 2 output pairs.

 

[Dan Pawlowski]

Rick

A clarification on that last clarification

all the amperage ratings really tell you is how thick the wires are connecting the die to the package.

Its all about current baby (amperage, is this a word?), 8 ohm, 4 ohm, 2 ohm these are very very low impedance loads which require lots of current to drive them (The more current an amplifier can deliver to a load the better). Ideally, the best amps can have their outputs shorted (heats the house) without the amp self-destructing.

Dan

 

[Baldemar Garcia]

Anthony,

Mind telling us the secret of exporting the Gifs in Unibox? I can't seem to shake the 'run time' error. I thought it was due to the fact that I was comparing two designs that were 'closed', but I see you're comparing two different drivers. Thanks for any help.

 

[Jack Gilvey]

How'd you get all those on the same graph? :b

 

[Anthony_Gomez]

Baldemar,
I too have the runtime error. I use a program called SnagIt to screen capture.
Jack,
Download the latest UNIBOX

 

[Jack Gilvey]

Ahh...thanks, thought I had it. :b