TOPIC:

Dear All,

If I purchase a Flex Eight as my crossover for my Linkwitz LX521 (stereo 4-way active system), how could I digitally add two extra channels of subwoofer using current miniDSP products, please?

Is it possible to use Dirac Live on top of the set crossover functions that Siegfried determined for the LX521’s?

I do have an old miniDSP 4x10HD which still works. What is the best way of using that piece of equipment for the two channels of subwoofer?

Best regards,
George. 

One way to achieve both of your goals would be to have an upstream  2 input, 4 output miniDSP that has Dirac Live capability. You would send two of the outputs to your Flex 8 crossover, and the other two to the subwoofers.

George,

What are your subwoofers?
Do they have their own crossover/eq??  Digital input??

Dave.

Hi Dave and Ultrasonic,

Thanks for getting back to me so quickly. I have looked at what you have both written and spent a bit of time mulling.

This started in an effort to future proof my LX521 system, because the miniDSP 4x10HD is now not made any more, to add flexibility if I wanted to try the alternative magnesium driver for the LX521, and to upgrade the quality of the DACs from the 4x10 quality to the Flex Eight quality, which I understand are of higher quality. (And I am not sure if my 4x10HD is working as well as it once did. I am getting nasty digital hash coming through at times which requires me to turn it off and restart the device. Not good.)

1.  So I guess a first question should have been, "Is there much or any sound difference between the 4x10HD and the Flex Eight?" Do you have any opinion on that?

Dave,
In answer to your questions, the subwoofers exists only in my head at present, hence this enquiry.

They will be driver-in-a-closed box DIY. I would like all crossover functions, input options, extra gain and volume control across the 10 channels to be provided by a DSP product, I hope.   Power amplification will be (another) Hypex nCore module per channel. The nature of the input will be determined by the options available on the DSP module. I would be prepared, if necessary to knock up a little extra bit of gain using a pre-amp board from Rod Elliott. I have one old (Schiit something USB/SPDIF/Toslink DAC with no volume control) and a new Topping e50 something USB/SPDIF/Toslink DAC with volume control, if that helps, along with the 4x10HD.)

Ultrasonic,
It appears that to stay in the digital realm for as long as possible, the only Dirac-able products with digital outputs which I could daisy chain to the Flex Eight and still have a pair of outputs to feed the subwoofers are the miniDSP Flex Digital, and the SHD and SHD Studio, the latter two both getting a bit dear, if I am to stay with the more modern miniDSP products.

The other way is that I could daisy chain the Flex Eight to any of the analogue-in analogue-out miniDSP options, and use analogue-miniDSP-analogue processing for the subwoofers' crossovers and delays if need be. This is a lot cheaper and has many more options available.

2.  Ultrasonic, have I understood what you were saying correctly? Is this what you were thinking about?

Dave and Ultrasonic,
3.  With this information, do you have any other or extra thoughts on my original question, viz. how to get the extra 2 channels for those subwoofers?
4. Do you think that delay between the daisy-chained miniDSP products can be reliably accounted for using the miniDSP products?

My room layout may turn out to be that the subwoofers might end up closer to the listening positions than the main speakers, so I need the ability to have the subwoofers delayed rather than the main speakers, so I need to keep that in mind. (I note that the 4x10HD can only delay the analogue channel outputs, not the digital outputs.)

5. It seems this can be dealt with two miniDSP boxes configured correctly. Is this correct?

And that just leaves the final fun, to work out whether to Dirac before or after the MSO process.
6. Which do you think would make more sense?

You can see why I took a little time to get back to this post.

Your help so far has been appreciated. I hope this has made things clearer.

Regards,
George.







 

Well, you're interested in a 5-way system and the Flex is only a 4-way system.  You've got a road block in front of you. 
You can use a combination of devices but, as you say, it may get very complicated regards latency issues.

I have some options for active/passive hybrid systems on the OPLUG.  Do any of those interest you?
You might also consider using subwoofers 'instead of' the dipole woofers for HT usage.  In that way you could function with a 4-way system in either case and just switch the configuration when necessary.

Dave.

Thanks Dave. 
<It seems you are interested in a 5 way system …>>

Aye, that I am!

It seem is I might be out on my own doing this, which in my soon to be dotage I might have time to try, but just not now.

Unless others have succeeded with a five/ten way setup.  

I am impressed with your hybrid work by the way!

With thanks,
George



 

Hello George, my 2 cents:
If you already have the 4x10 you could get your subs and try it first.
The value of the subs + a better tuning would already be a good step up. And then you could think about a "better" unit.

Now if you’re interested in the shd I can say that I daisy chained up to 3 units in the past with no issue.
In parallel or in serie I always had enough delay to integrate everything, even with subs right behind me.
But I simplified it and now only have SHD studio + flex8 regular (the studio splits between subs and mains).

Also, I don't know enough the LX filters but could you try a passive crossover between mids and highs? This would probably be the easiest.
 

grosso wrote:

Now if you’re interested in the shd I can say that I daisy chained up to 3 units in the past with no issue.
In parallel or in serie I always had enough delay to integrate everything, even with subs right behind me.
But I simplified it and now only have SHD studio + flex8 regular (the studio splits between subs and mains).


 

I'm not sure how you managed that, because the SHD unit has a significant inherent delay of 25mS.  'Depending upon how you daisy-chained them, you could end up with a large relative delay difference from branch to branch.

Dave.

GeorgeBoles wrote:

Thanks Dave. 
<It seems you are interested in a 5 way system …>>

Aye, that I am!

It seem is I might be out on my own doing this, which in my soon to be dotage I might have time to try, but just not now.

Unless others have succeeded with a five/ten way setup.  

I am impressed with your hybrid work by the way!

With thanks,
George




 

As correctly pointed out by @grosso, you already have a five-way system.  You just need an external DAC to make use of the 4x10HD digital output.
I know audiophiles have upgrade-itus often, but the simplest solution is usually the best.

Dave.

dreite wrote:

I'm not sure how you managed that, because the SHD unit has a significant inherent delay of 25mS.  'Depending upon how you daisy-chained them, you could end up with a large relative delay difference from branch to branch.

Dave.

Right that was confusing, I tried a bunch of different combos over the years and don’t remember if I did 3 in serie.
But probably as I played a lot with them.

Basically it went from 1 shd, to 2 units in cascade, and then 3 in 1 master/2 slaves.
Meaning 1 SHD studio driving 1 SHD per side, for 4 way + 2 subs (from Studio spdif).
And now the flex8 replaces the 2 SHDs.

I remember searching for this delay when starting and I used your 25ms reference at the time as default.
Value that I should have had to use to compensate between subs and mains for example, mitigated by their physical offset.
But it’s never been the case, I always needed much less in all combos, either between subs & mains, or between low & high on mains depending of the SHD setup.
I don't remember the number maybe more around 10ms, now maybe it depends of the amount of processing I don't know.

 

If you "Y"ed one SHD into the other two that would be okay from a delay standpoint.  But boy-o-boy that's an expensive and complicated 4-way crossover. 

Dave.

dreite wrote:

If you "Y"ed one SHD into the other two that would be okay from a delay standpoint.  But boy-o-boy that's an expensive and complicated 4-way crossover. 

Dave.

It sure was working!
And sure was expensive too, but it was a slow build up.
The flex8 is much easier to tune, so many times I messed up with multiple presets.
But all balanced had advantages.

Thanks to all. 

I shall fiddle with the 4*10HD first as you say because it is there, once I am back home from holidays, from whence this idea burgeoned. 

If I want to pursue the Flex solutions I will do that at a later date, or if forced to by the nasty, loud digital noise intermittently on the 4*10.  

It does look as if a Flex Digital or SHD Studio ( or perhaps the DDRC-22D??) would daisy chain to a Flex Eight and give me 10 channels, with some Dirac in there too, if I had to. 

Have I got this right?

  Best regards 
George