TOPIC:

I have been very happy with my minidsp shd.
Initially, I thought of building my own speaker two way and use the minidsp shd to power two stereo channels with amplifier and a digital crossover.
Going low implies making two many compromisies on a two way speaker, so I began simulating a three way in vituixcad.
I have simulated an active low, passive XO on mid-high, with a very flat FR, but it  looks quite a hassle to build!

What would be the best way to add a third stereo channel to my minidsp shd?

One basic idea: SHD analog out to 8x10HD, make all the XO in the 8x10. 
Another idea is plate amps: SHD analog out 1 with digital low pass to passive amp LF, SHD analog out 2 with digital high pass to active plate amp MH+HF, add Low pass and high pass FIR in the plate amp for MF/HF crossover.

Are those ideas feasible? What are the tradeoffs: it looks like I am adding another AD/DA converter with both options, right ? I use Dirac on the SHD.

Regards
Luc 





 

I have currently a DIY setup that is similar to what you want to do.

I have a 2 way 6.5" bookshelf in sealed box. It goes down to 80Hz or so and then naturally cuts off. I use SHD for the active crossover.

Below 80Hz, i connect the LF output (that also drives the amp for the 6.5" woofer) from the SHD to a 2x4HD which drives subwoofer with a steep slope.

If you play around with the delay and cutoff, the sub will blend with the natural cutoff of the 6.5" very smoothly.

The big caveat of SHD is that it doesn't support FIR filters so if you plan to use some correction software to tune the mid/high then you are out of luck.

To me that's a HUGE shortcoming of the SHD. Technically it is definitely doable as the new Flex can do it. But somehow minidsp decided not to support FIR filters in SHD.

jmpsmash wrote:

The big caveat of SHD is that it doesn't support FIR filters so if you plan to use some correction software to tune the mid/high then you are out of luck.

To me that's a HUGE shortcoming of the SHD. Technically it is definitely doable as the new Flex can do it. But somehow minidsp decided not to support FIR filters in SHD.

No miniDSP unit does both FIR filtering and Dirac Live. Essentially the same DSP capability is used for both, so it's a case of only one or the other being possible.

The Flex allow loading of FIR filters. I assume if what you said is correct, then Dirac is disabled. Which is fine.

In the SHD that's not an option. FIR filters are not supported. period. Dirac enabled or not, FIR not supported.
 

jmpsmash wrote:

The Flex allow loading of FIR filters. I assume if what you said is correct, then Dirac is disabled. Which is fine.

In the SHD that's not an option. FIR filters are not supported. period. Dirac enabled or not, FIR not supported.


 

There are two options:

1. You have a device that does FIR filtering but not Dirac Live e.g. 2x4 HD or Flex without a Dirac Live Licence.
2. You have a device that has Dirac Live but not FIR filtering e.g. DDRC-24, Flex with Dirac Live licence or SHD.

There is no device where you can choose to turn Dirac Live off to use FIR filtering, or vice versa. Much as it might be nice to have the option  .

So if one buys a Dirac Live version of Flex, then there is no way (software config change, firmware reload) to use FIR filter at all?

That's not very clear from the minidsp description.

 

jmpsmash wrote:

So if one buys a Dirac Live version of Flex, then there is no way (software config change, firmware reload) to use FIR filter at all?

That's not very clear from the minidsp description.

 

What I meant was that you can't easily toggle between Dirac enabled/disabled to be able to use FIR filtering. I expect it is technically possible to revert to a pre-Dirac version but you'd need to contact Support to confirm if this is important to you. However, if someone wants to be able to use FIR filters the thing to do is to buy the (cheaper) hardware that doesn't have Dirac Live  .

Perhaps it should be more clear from the product description. Right now it is very misleading as the spec page clearly lists both Dirac and FIR support and mentions nothing about how complicated it would be to support either or both in the same unit.
 

jmpsmash wrote:

Perhaps it should be more clear from the product description. Right now it is very misleading as the spec page clearly lists both Dirac and FIR support and mentions nothing about how complicated it would be to support either or both in the same unit.
 

Yes, I think that's a fair point. Perhaps you could start a thread the Flex section to ask for clarification on this? Others interested in the Flex series will be more likely to see it there, and miniDSP staff will probably be more likely to respond sooner too.