15" driver for Dipole sub

[Rud-e]

Hi Guys

can one of you please help me choose a 15" speaker that I can use for a Dipole sub. and it needs to be very fast , I will be using it with a 1M ribbon and a 9" paper speaker also dipole.

[Hennie]

Hi Rud-e,

How are you going to equalize the bass, i.e. are you looking for a high Qts driver for a passive application or a low Qts driver and active EQ?

Passive Options:
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High Qts:
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Use the Hawthorne Audio Augie and one of their baffle designs suitable for this driver. You will have to import this driver:

http://www.hawthorneaudio.com/drivers.htm

Moderate Qts:
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Use the Visaton BGS 40 8 OHM and base your design on the Visaton NoBox design:

NoBox:

http://www.visaton.com/en/bauvorschlaege/breitband/noboxbb/index.html

BGS 40 8 OHM:

http://www.visaton.com/en/chassis_zubehoer/tiefton/bgs40_8.html

You will have to import this driver. Alternatively, find a pro driver with similar or close T&S paramters and use the same baffle. As long as the Qts is not too different, you can always use a series resistance to tune it for the baffle.


Active Options, Low Qts:
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There are many professional drivers suitable for an active app, some are available locally or have local agents. Watch the voice coil cooling design in order to avoid wheezing at high excursion. P.Audio, BMS, B&C and Eighteensound come to mind.

There are also low efficiency options like the Parts Express 15" subs but again most of these will have to be imported.

The passive options listed above obviously been tested in dipole designs so they should be OK in terms of air noise.

[DRNB]

Rud-e, we've got very few, actually Martins the only one I know off, that has tried a dipole system before. Therefore pleaaase!!! If you don't mind, post the project on here. It would be very interresting to see.

How are you going to equalize the bass, i.e. are you looking for a high Qts driver for a passive application or a low Qts driver and active EQ?

@ Hennie,
Just a question, but if Rud-e would like a fast driver (duck), wouldn't you say that a low Qts active driver would be the better option?

[Timber_MG]

Also, what is the requirement for SPL and extension? If you're supplementing it with a monopole for sub (real dipole subs....get expensive and big real quick) then I would look at a nice HE pro-driver for say 60-to-whereever. For LE drivers I would be tempted to get the Parts-Express RS line of subs due to their motor linearity. However a dipole woofer(especially on a small baffle) eats up excursion like there's no tomorrow for even very moderate SPLs.

What are you pairing this with? the power response is hard to match with open-baffle designs at crossover, just to warn you.

And as to "fast".....that is a highly hyped sales myth I will spare you...95% of that is proper integration with the ways above and less FR from bass-lower mid due to the perception aspects of lean bass. I highly recommend you investigate multiple smaller subs and perhaps one or two larger diameter pro-type drivers to pair with the ribbons as it'll make your live around crossover much, much simpler (and so will a decent active crossover)

But as per Norval, post the specifics, drivers, baffle config and intended crossover frequencies.

Personally I'd investigate mating a pair of pro-sound 12"ers to mate to the line if the baffle allows and multiple monopole subs spread around the room below..

[Hennie]

Just a question, but if Rud-e would like a fast driver (duck), wouldn't you say that a low Qts active driver would be the better option?

Norval,

There is a saying that goes something like this: "Fast bass is called treble" (duck)!

With a higher Qts driver you will have to look at the total response, i.e. driver plus baffle. The Augie will require quite a narrow baffle due to its Qts, while I think the Visaton option will sound nicely balanced. The Visaton is quite close to a Beyma OEM I used once, and that sounded "fast". Apologies Timber, I know you Germans prefer "dry"....

But as Timber said, open baffles eat excursion really quickly, and a monopole sub may be required depending on listening habits and music taste.

An 8" paper mid supplemented by something like a B&G Neo3PDR in dipole mode may reduce power response problems. There will still be a jump in the power response at crossover, but it will be better than a monopole ribbon. Otherwise absorb some of the back radiation of the mid driver to get a smooth changeover.

[Shonver]

About fast bass...

The perception of "fast" bass seems to correlate with low Group Delay (low-Q roll-off). "Fast bass" is a poorly chosen term, and is hated by technically-minded persons, who know that nothing fast happens low down. For instance, a system can be EQ-ed from being sluggish/bloated/slow to lean/dry/fast. It has nothing to do with the speed of movement of the speaker cone.

So, the questions about the proposed system's intended configuration (active/passive/etc.) becomes more relevant in this respect.

[Timber_MG]

I have run out of 15dB shelves and seen high power amps clip into an open baffles EQed to go low so quick it is scarry. Sometimes you think the drivers want to land on your lap if you forget to add a dynamic filter in the DCX, but fortunately pro-sound drivers survive such treatment more readily.

I quite like some shelving parametric EQ to adjust to the music I am listening to. POP often gets a 1kHz -3dB(or more) 6dB/oct transition shelf.

I like bass, but hugely prefer neutral bass, not overbearing but also not absent till you crank it and not the kind that is limited by system limits, compression and wind-noise. In larger pro-sound setups you notice this kind of a setup when doing a sound-check on a well-miced bass-drum and snare. When it is set up right all of a sudden the bass doesn't require a crazy HF boost to be audible in complex passages anymore.

[Rud-e]

 

I see there is a alot of opinions out there again. fast bass is basicly very fast speaker action (impulse response) . I actually have two in my posession that is extremely fast but they are custom made units. I am looking at a alternative

the system is driven passively and is using a 52mH choke on the bass driver.

I like the Augie. that looks like the ideal type of driver I should use

[Shonver]

I see there is a alot of opinions out there again. fast bass is basicly very fast speaker action (impulse response) .

Here we go...

For a woofer to have exceptional impulse response (very fast speaker action), really requires that it have an extended high frequency response. Unless you are trying for a full-range single-driver solution, this is not required for a woofer. What you do want is for it to be well damped. This relates to how quickly energy that is input into the system is released as acoustic power. A highly damped system will sound ''quick"/"fast", whereas an underdamped system will sound bloated and boomy.

I promise you that a "fast" woofer and "slow" in-system, if EQ'ed to the same roll-off curve, will sound the same, all else being equal.

[DRNB]

Heh heh, 
I knew you were gonna get some reaction with regards to your "Fast driver" request Rud-e. 

But read carefully Rud-e, and you'll note that there has not really been a difference in opinion here. Also remember that an open baffle system is gonna be very chalenging, and think the advice these other three carracters are giving might just come in handy 

[Rud-e]

But read carefully Rud-e, and you'll note that there has not really been a difference in opinion here. Also remember that an open baffle system is gonna be very chalenging, and think the advice these other three carracters are giving might just come in handy 

I hear what every one has got to say and I sit back and smile. it is all very well and technical. I just wanted another driver with a very high Q for open baffle work. just to compare to what i got.

as is it is working 100%. it is used for Hifi not prosound so SPL is the last thing that i am interrested in. I actually have to resist the fille (9" driver and the ribbons to integrate with the 15")

I also chose a 15" becasue the sound of 2 voice coils in parralel is just awfull so no dual 12" setups for me.

anybody interrested can contact me if they want to hear it

[Shonver]

Rud-e

What design are you using for the dipole sub? Dimensions?

Beside the 52mH inductor, are you using any equalisation?

[Timber_MG]

It is certainly an interresting project.

You have some very odd conceptions of causation of a certain sound and it would be interresting to hear some of your thoughts.

The use of Pro-sound drivers is most certainly not precluded to use in high-SPL applications only. Their characteristics have many benefits in comparatively high-power applications such as open baffles and distortion reducing features such as shorting rings and decent motor design are the rule and not the exception. Some pro-sound drivers have exceptionally well engineered motors, baskets, paper cones and terminations making them well behaved and allows for simpler crossover topologies, low distoriton and a host of other disirables.

It would be interresting to hear some more about your 1m tall ribbons, DIY, one of Dr. Sing's creations or something else?

[Rud-e]

I am using a prosound driver for the sub. 52mh choke and 33R resistor parallel to the driver. I really do not know the make of the driver. no eq done to it, the box is a basic S construction closed top and bottom with the mounting area being slightly tilted the dimension is roughly 50 x 50 cu

*removed at the request of the originator*

[Rud-e]

What is a Singh ribbon? Please tell us more.

a locally produced ribbon - but all are just prototype units

*edit Mod*