A thread for Tysen and variations on FAST

[chrisb]

Originally Posted by mattitos

Hi,

has anyone the Tysen FAST speaker building plans with passive crossover available? I am especially interested in the variant with Alpair drivers. If anyone has plans available, I would apprieciate if he/she could share them with us!

The XO frequency implemented in the FF85K/SDX7 version of this design shown earlier was IIRC, around 300Hz ( 333?), specifically chosen to take advantage of the excellent performance of the Fostex. (think of it as a very wide band 3/4" metal dome tweeter with an unusually large surround, and very low Fs )

Between the very large value of caps required for even a simple 1st order slope* ( eg circa 130mF) and the power required that would subsequently be wasted if attenuation was required due to a big difference in sensitivity between drivers, the total cost of implementing a passive XO could quickly skyrocket.

(* don't even think about the cost of a 4th order LW for this type of application )




Of course if you already have a high powered amp the sound of which you're happy with, that's great; but in our case we'd generally be using lower powered tube amps on the wide-band ( a magical combination with the FF85K ), and a passive XO would choke the life out of the system.


It was also assumed that since most DIYer's contemplating this type of project likely have more than a couple of amp stages kicking around, a simple dedicated frequency PLLXO could be put together for little money, and yield the advantages of bi-amping; not the least of which are improved dynamic capabilities and flexibility of level adjustment.

In the case of the Planet10 system pictured at the beginning of this thread, I'd suggest you read posts 1 - 4 for an explanation of how / why we chose this route.

One of the huge advantages of the PLLXO / bi-amp method, particularly if both amps have volume controls, is the flexibility it allows for trying different drivers for either bass or mid/high range - the only time you'd need to change passive components would be if either of the amps were changed with something with a different input impedance, or if the XO point itself were moved.

but back to your original question?

I'm not sure if Dave or anyone else has actually crunched the numbers on a passive high level XO - of course you'd need to know exactly which drivers were intended.

[planet10]

No one has done a passive XO for Tysen as implemented (that i know), Passives have been left for another implementaion with more appropriate woofers. Now that FF85 has been discontinued, we'll likely wait for Alpair6.2 and Alpair6p (the protos are superb) for small speakers. Currently working on a statement version of Tysen with 4 SDX7 & Alpair7 per side. With a lower XO yet, it almost by requirement will need to be active.

[Bigun]

Originally Posted by planet10

we'll likely wait for Alpair6.2 and Alpair6p (the protos are superb) for small speakers

maybe a bit OT, but any rumours of a more efficient driver with a more friendly impedance from Alpair, something that can really replace Fostex ?

[simon dart]

Hi Dave,

I'm very interested in your Tysen 4 SDX7 & Alpair7 project. What kind of active xo are you heading toward? In my experience few active xo's do as little damage to the treble than a good foil cap. I hate grainy treble. Obviously FAST rules that kind of solution right out! Is a PLLXO likely to crack the problem?

[planet10]

Originally Posted by Bigun

maybe a bit OT, but any rumours of a more efficient driver with a more friendly impedance from Alpair, something that can really replace Fostex ?

Mark is really focusing on getting efficiency up, but will not compromise the well controlled behaviour of his cones and the extended response (at both ends). That Mark has managed to find himself working with some exFostex luminaries (ie Matsubara-san spider on the A7/A12 and all the upcoming Gen2 drivers) we can expect more of their vast knowledge flowing into the MA product. Also working with paper will give efficiency a lift (i've been living with an early set of the A6p protos, and these (roughly comparable to FF85/FE83 in terms of niche) are of similar efficiency with more extended bottom.

As well, real world efficiency as measured in the field with a pair of ears seems to be higher than the ears would indicate (that may be pcho-acoustic due to the generally higher downward synamic range)

dave

[planet10]

Originally Posted by simon dart

Hi Dave,

I'm very interested in your Tysen 4 SDX7 & Alpair7 project. What kind of active xo are you heading toward? In my experience few active xo's do as little damage to the treble than a good foil cap. I hate grainy treble. Obviously FAST rules that kind of solution right out! Is a PLLXO likely to crack the problem?

I will be getting the basic configuration down using a DCX2496 (with O'Netics transformers all round -- hopefully making it listenable to humans as well as the measure mic). If i can get away with PLLXO i will, otherwise, buffered, stacked PLLXO, or PLLXO on top and more tradiitonal active on the bottom. The greater extension of the A7 gives more latitude.

To start i flipped my FonkenWoofs upside down (PP SDX7), a flipped over set of R1 dMar-Ken7, and will have a 1st draft PLLXO to get a feel for them. 1st set of A7eN is just being finished up (and i sent a set to Bud),

If this one works out, i'm thinking of A12 + 2 or 4 SDX10. That in theory would plumb the depths of LF & dynamics without resorting to horns.

dave

[Henkjan]

there was a design in a german diy magazine which had the Alpair5 and the Alpair10bass with a passive XO. just looking at thhe complexity of that XO would explain why both Dave (with the Tysen) and I (with Nescio) did not go the passive route.

[ScottG]

It's too bad about the supply issue, it's a very nice looking package.

[ljfont]

Hello,

Since the BSC is built into the A7, do you find that your PLLXO can go lower?

Was your first tysen's XO point chosen higher to compensate for BSC. (Fostex)

Thanks.

[planet10]

The XO is picked based on a lot of experimenting with a DCX2496 (the one i had to use, something only a microphone could love) and then some fine tuning.

dave