Recommendations for cone mid dome tweeter to match with DA 17w75

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Ok, so i did a search and i can not explain why I come up with zero but I need recommendations for some drivers. I am using Dynaudio 17W75 and want to make a 3 way system and am looking for a good mid and tweeter. I am NOT looking to spend $300 per driver so I want something of reasonably good quality but not the most exotic. I was thinking cone mid (4 or 5 inch) and silk dome tweeter. Any idea's. Thanks all.
 
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http://www.gattiweb.com/images/dynaudio/17w75_data.pdf

Hi,

Tricky drivers to work with, starting off with Qts = 0.8 doesn't help.
Presumably designed to implement the bottom end of baffle step
correction with the box, 15L per driver gives a box Q of 1.25.

25L per driver Q drops to 1.1 and TBH there is not much point
having a box larger than driver Vas (22L), it just gets silly.

Aperiodic loading might help, but its pretty hit and miss.

The driver looks about 84dB, two in parallel around 90dB,
but with baffle step your looking at around 87dB for the
mid/treble sensitivity.

There is no ideal combination of md and treble to go with
the above drivers, you have loads of choices, though if
pushed i'd say don't chuck money at it, the drivers
aren't that great, though they were expensive, but
probably given the specs pretty good for sealed 2-ways.

If further pushed I'd say try using them in a sealed and
well stuffed version of this : Zaph|Audio - ZDT3.5

Balancing is a tricky business, for the above you can try
putting a resistor in parallel with the BSC inductor to
reduce BSC and adjusting mid and treble by lowering
their values to suit, until bass and mid/treble are
balanced.

I suggested the above because it allows your units
to work well into the midrange, and they have a good
reputation, and the additional units are fairly cheap,
but very good over their range, very good value.

Furthermore, most of the difficult design work is done.

rgds, sreten.
 
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Ok, so i did a search and i can not explain why I come up with zero but I need recommendations for some drivers. I am using Dynaudio 17W75 and want to make a 3 way system and am looking for a good mid and tweeter. I am NOT looking to spend $300 per driver so I want something of reasonably good quality but not the most exotic. I was thinking cone mid (4 or 5 inch) and silk dome tweeter. Any idea's. Thanks all.

Hi jimbones,

Sorry if this is somewhat OT but I think you would be better off if you
build a nice 2 way system.

This midwoofer is made for sealed boxes and if properly damped in about
15-20 liters, the free air resonance should rise only by a few Herz with Qtc
at 1,0 or a little less. Dynaudio 17W75 is certainly a great midrange driver
too and if desired can be filtered with a 1st order filter.

Allthoug published Fs=40 Hz looks exciting, in real world this is going to
be more like 50-55 Hz in free air. Nothing to be worried about, just needed
to point out. Having said that, F3 is expected near 55 Hz.

There are many good tweeter drivers to use with and in theory
you only need to pick one you like, for example:

Usher 9950C-15 1-1/8" Shielded Textile Dome Tweeter 276-610
 
Thanks sreten and lojzek. I am not worried about the low end performance of the driver cause i use a sub. I think the 17W75 has great speed and is tight so I like the bass from it. I'll go two way and build a "monitor". The tweeter will have to be crossed over fairly low though.
 
This midwoofer is made for sealed boxes and if properly damped in about
15-20 liters, the free air resonance should rise only by a few Herz with Qtc
at 1,0 or a little less. Dynaudio 17W75 is certainly a great midrange driver
too and if desired can be filtered with a 1st order filter.

Allthoug published Fs=40 Hz looks exciting, in real world this is going to
be more like 50-55 Hz in free air. Nothing to be worried about, just needed
to point out. Having said that, F3 is expected near 55 Hz.
[/URL]


Hi,

In a box the same as Vas (22L) the Fs will rise by root2, x1.41.
In a 22L box Fbox is 56 Hz. F3 is 42 Hz but won't sound like it
due to the 2dB peak at 70 Hz caused by the Qbox of 1.13.

To get Q=1 you need a 40L box, 15L is Q=1.3, 20L is Q=1.16.
15L F3 is 45Hz, but with a 3dB peak around 80Hz, here you
really do need the typical +/-3dB spec for response.
And we haven't gone into baffle step issues ....

40Hz Fs isn't that exciting and it will be the same as free air, it is free air.

You can put a single inductor (+ probably a zobel type network) on
the bass driver dimensioned for BSC, but you need to carefully match
the tweeter roll-off to the drivers acoustic roll-off at the x/o point.

rgds, sreten.

FWIW about 15L per driver rolled off by an AV amplifier at 80Hz
should moreorless work, the acoustic roll-off will be near butterworth
4th order with a typical AV amplifiers 2nd order L/R high pass filter.
 
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Downer sreten. sounds like you REALLY don't like going down this path.
I was thinking since I have 4 of them that a 3 driver/2 way would be possibility.
But from what you are saying, even if it works it won't be wonderful.

Hi,

No. not at all. A 3 driver 2-way is going to be presumably
a MTM, the other options being a 2.5way MTM or TMM.

Whilst you can do this, you would be presumably relying
on the driver spec for its response roll-off to mate to the
tweeter, and that is a whole can of worms even if you do
it properly on paper.

One spec sheet from years ago cannot be trusted, though
you would expect Dynaudio to be more accurate than most.

IMO if pushed, like I said before, take the drivers top end
response out of the equation by going for a 3/3.5 way.

If you have measuring equipment and know how to use it
then that is a completely different ball game, as well as
having simulation software and knowing how to use that.

Technically it may be hard to understand why I suggested
using your drivers as the bass units in the ZDT3.5, but it
it is a relatively safe approach, with no design, simulation
or measurement capabilities seemingly apparent.

Its just my opinion its the safest approach, as it will work.

As a 3 way its more like a 2 way with a supertweeter than
a typical cone midrange 3 way, exploiting your drivers more.

YMMV, but you need some serious design skills for a 2 way.
You do for a three way too, but its been done, and the
drivers roll-off doesn't enter the tweeters x/o equation.

rgds, sreten.

Further thought suggests you might be happier with using
the ZDC3 x/o, i'd say almost certainly in ~ 30L boxes for
both drivers, its a little simpler / cheaper, and IMO keep
the original R4 and R6 values, YMMV.
 
Hi

Dynaudio had a 2-way MTM floor standing kit at one time named the TWYNN. It used your drivers plus a D-28 AF tweeter. The cabinet was a complicated design that used different volumes for each of the woofers but a common crossover output to these drivers wired in parallel. The x-over design was included in the literature. Might be a good starting point.

Regards
Paul
 
Hi,

In a box the same as Vas (22L) the Fs will rise by root2, x1.41.
In a 22L box Fbox is 56 Hz. F3 is 42 Hz but won't sound like it
due to the 2dB peak at 70 Hz caused by the Qbox of 1.13.

40Hz Fs isn't that exciting and it will be the same as free air, it is free air.

rgds, sreten.

I agree with your data analysis. The same info I get from simulation software.

I shoud have been more precise and said that my predictions were
based on experience measuring different brands of drivers. After installing
in a box and all being properly damped , the measured data were not
the same as simulated.

Either I'm doing something wrong or the theory should be redefined ;)
 
I agree with your data analysis. The same info I get from simulation software.

I shoud have been more precise and said that my predictions were
based on experience measuring different brands of drivers. After installing
in a box and all being properly damped , the measured data were not
the same as simulated.

Either I'm doing something wrong or the theory should be redefined ;)

Hi,

You can't trust specs, the cheaper the driver the more likely
they are wrong. The theory is fine, just the data is wrong,
and if your measuring, measure the real driver parameters.

rgds, sreten.
 
Hi,

No. not at all. A 3 driver 2-way is going to be presumably
a MTM, the other options being a 2.5way MTM or TMM.

Whilst you can do this, you would be presumably relying
on the driver spec for its response roll-off to mate to the
tweeter, and that is a whole can of worms even if you do
it properly on paper.

One spec sheet from years ago cannot be trusted, though
you would expect Dynaudio to be more accurate than most.

IMO if pushed, like I said before, take the drivers top end
response out of the equation by going for a 3/3.5 way.

If you have measuring equipment and know how to use it
then that is a completely different ball game, as well as
having simulation software and knowing how to use that.

Technically it may be hard to understand why I suggested
using your drivers as the bass units in the ZDT3.5, but it
it is a relatively safe approach, with no design, simulation
or measurement capabilities seemingly apparent.

Its just my opinion its the safest approach, as it will work.

As a 3 way its more like a 2 way with a supertweeter than
a typical cone midrange 3 way, exploiting your drivers more.

YMMV, but you need some serious design skills for a 2 way.
You do for a three way too, but its been done, and the
drivers roll-off doesn't enter the tweeters x/o equation.

rgds, sreten.

Further thought suggests you might be happier with using
the ZDC3 x/o, i'd say almost certainly in ~ 30L boxes for
both drivers, its a little simpler / cheaper, and IMO keep
the original R4 and R6 values, YMMV.


I like your idea of using the existing ZDT design. I am not a strong designer and i don't have measuring equipment (but I do have access to it). I do prefer to use a low risk solution that I can tweak to optimize.
 
I like your idea of using the existing ZDT design. I am not a strong designer
and i don't have measuring equipment (but I do have access to it).
I do prefer to use a low risk solution that I can tweak to optimize.


Hi,

Well as you said you not too concerned with the bass end, but it
needs some attention. Both drivers in a sealed well stuffed box
of around a cuft (28L) or a little higher (35L) is as low as you'd
want to go for the box volume.

According to driver specs you will get a peak in the bass, around
3dB at 80Hz. Using the reduced BSC version of the ZDT3.5 x/o,
the ZD3C x/o, with the ZDT3.5 driver layout will compensate
the peak somewhat, and make it look more like a shelf.

The ZDC3 is a 3 way, not a 3.5way, but it should work pretty well.

rgds, sreten.
 
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