The Adire TUMULT is here! (1 Viewer)

[Craig Woodhall]

I was gonna make a coffe table (not end table) sub about 8ft^3 with a 6" or 8" port.. Maybe this design isn't the best way to go. I already have a 10ft^3 BDP1803(17hz), this new Tumult is just to compliment it.. I have 800w @4ohm of Crest power available to each enclosure.. Im thinking Jack's 150L 16hz or 17hz with PR's is looking good.. Just worried about blowing out the PR's in a real low bass scene (don't have any rumble filter).. any input on PR's vs. ported enclosures for this driver?

Craig

 

[Jack Gilvey]

any input on PR's vs. ported enclosures for this driver?

Did you read my thoughts just a few posts up? And the other thread?

 

[Chris Tsutsui]

I believe that just because a driver has Linear response and has XBL2 or Video stage 5 or whatever doesn't mean much towards "sound quality".

In conclusion to what I've read so far it looks like I might not be getting a tumult. I know that it's hard to answer questions about a driver before it's release but if I wait until the driver comes out the cost would be too high.

This sort of puts people into an awkward position which is why I believe in respectable beta testers and reviews before the presale opens.

Sorry if this appears as a complaint but the sarcastic posts like the one above have been getting to me.

 

[Jack Gilvey]

Sorry if this appears as a complaint but the sarcastic posts like the one above have been getting to me.

What's sarcastic? The question has been adressed over and over, and it gets frustrating when answers are posted and not read, even in the same thread. Did my last "sarcastic" answer to you "get to you"? They were legitimate questions I posed, and much can be learned by answering them.

 

[Brian Bunge]

Yes, Chris, what you are reading from Jack and myself is not sarcasm, but frustration on our part. We've both seemingly answered the same 4-5 questions 10 times now. And not only here, but on various other forums as well.

I think the top 3 would be:

1) Sound Quality? YES, "extreme" SQ due to the XBL^2 motor.

2) Ported? NO, you cannot use the driver to it's full potential as it's virtually impossible to affectively port it.

3) PR'd? Yes, dual Stryke 18" PR's with dual spiders with 2500g or so of mass each, depending on enclosure size and tuning.

I'll let Jack fill in any other repeated questions! (Hey Jack, why not start a "Tumult FAQ" thread?)

Brian

 

[Jack Gilvey]

I wonder what the "car audio" definition of "SQ" is? Maybe we're talking about different things? I'm usually left a bit in the dark by the car crowd.

I'll let Jack fill in any other repeated questions! (Hey Jack, why not start a "Tumult FAQ" thread?)

No thanks, bro. A little reading never hurt anyone.

 

[Craig Woodhall]

Jack,

As far as PRs go, I don't know of any PRs that I'd trust to work long-term. Start with extremely high linear displacement (and with XBL2 this motor can maintain all its force out to those limits), meaning at least 2 high excursion 18" PRs (or 4 high excursion 15" PRs). Then add in smaller boxes (under 5 cubic feet; larger than that and the response starts to get ragged) with low tunes, and you're looking at PRs with at least 2 kg of moving mass EACH. There aren't any PRs that I know of that I would expect to survive long-term with that much moving mass (nearly 5 pounds).

and the fact that 2 of the PR's would cost me $500CDN to get them in my hands.. I just want to do it right the first time..

Craig

 

[Jack Gilvey]

I know you're no newbie, Craig, just wanted to make sure you saw the post. As far as PR's holding up, the fact is that in the alignment I posted, the PR's (if using but a pair) do go into overexcursion down near Fb at extremely high levels (the sims assume that such deep signals are present at the same dB level as the rest...very uncommon). The dual-spider 18" Stryke PR's are meant to hold quite a bit of Mms, and John seems quite confident in them, but this driver will ask a lot of them.
You can certainly try a 6" flared port or dual flared fours (the cheapest way to go). It may well be that it's already loud enough for you by the time any ill effects from underporting rear their heads, depite what the sims say.
(btw, I wouldn't hold my breath waiting for Dan to actually recommend the Stryke PR's. Or for John to recommend a Tumult.)

 

[Craig Woodhall]

(btw, I wouldn't hold my breath waiting for Dan to actually recommend the Stryke PR's. Or for John to recommend a Tumult.)

yes, that i gather.. funny thing is, Dan's drivers and Johns PR's will probably end up working together and won't even know any of the politics

 

[Jack Gilvey]

I only have 800w available to the driver so maybe I won't run into the underporting or the over excurting PR's anyways.

Agreed, with that amount of power input you should be ok even with a 6" flared port.

 

[Craig Woodhall]

An 8" should be fine as far as compression/noise is concerned, but it'll have to be quite long...what alignment do you have in mind?

i was looking at around 8ft^3 (long like a coffee table) where the port could run along the length (almost 4') of the enclosure.. i think i like the easier construction and the smaller size the PR'd enclosure would offer.. Would i need much bracing in a 5ft^3 enclosure with the Tumult and (2) 18" pr's? probably not, huh..

Craig

 

[Scott Simonian]

Wouldnt 2 5 pound PRs make the group delay horrid? I mean, thats a lot of weight to move. Wouldnt they move slow as hell? I think IM wrong in any case. I still havent seen the power of the Tumult.

 

[Anthony_Gomez]

Scott, Group delay is a function of the change in phase with respect to frequency. AFAIK, it has nothing to do with the mass of the PR.

 

[Mark Seaton]

To expand on Anthony's explanation, group delay is directly tied to the shape and extension of the subwoofer's frequency response. A peaky response will have more group delay. The really tricky part is that any EQ and even the room also affect the observed group delay. Mass alone has nothing to do with group delay unless you also define all other parameters.

 

[Scott Simonian]

I meant that maybe in the frequencies where the PR is working. I thought it might move slow. Guess not.

 

[Jack Gilvey]

It's tempting to think of a driver as "pushing and pulling" the resonator(s) in a reflex system. This idea, while seemingly intuitive, gives the wrong impression of what's actually happening, and leads to the conclusion that such heavy things must be "slow" (based on an inaccurate/incomplete mental model).
In fact, a heavier PR will actually have a lower Fs, pushing the system's notch in FR lower and smoothing out the curve, possibly leading to better transient response than a lighter Mms..all else being equal.
Here's a good article on bass reflex:
Link Removed
And on PR:
http://www.stryke.com/prfaq.htm

Would i need much bracing in a 5ft^3 enclosure with the Tumult and (2) 18" pr's? probably not, huh..

I'd still brace it well.

 

[Dennis XYZ]

In fact, a heavier PR will actually have a lower Fs, pushing the system's notch in FR lower and smoothing out the curve, possibly leading to better transient response than a lighter Mms..all else being equal.

Good one, Jack. Here's an easy mental image for those who don't get it. If the PR has infinite mass, it won't move at all and the enclosure will act like a sealed box. Sealed boxes generally have the lowest group delay (best transient response.)