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DSP

Pirateboy

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Hi.
I'm really interested in adding dsp into my system & have been looking at the minidsp DDRC 24 which comes with the mic. I've been looking through the forum but it gets very technical very quickly!
I have a dedicated listening room, 28L 15w 9h, carpet, rug, soft sofa, 2 very small windows on opposite sides of the long walls, bookcases, bass traps, diffusers, etc, I've done as much as I can on that front.
System is a turntable into phono stage into preamp, dac/streamer into preamp, preamp into monos, speakers & 2 rel subs into the monos.
I've heard dsp is a great way to tighten the bass up & get the best out of subs & I'm thinking the DDRC 24 would be a good place to start?
If I connect the dac/streamer by toslink, the phono stage by RCA & then the DDRC into my preamp, would that work & let me correct the subs even though they're wired with the high level connection to the same terminals as my speakers?
Thanks in advance.
 

NTK

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This is the recommended configuration per miniDSP's application notes.
https://www.minidsp.com/applications/digital-room-correction/ddrc-24-for-2-1-system
C3.JPG


You'll want to put the miniDSP after your phono stage/pre-amp. The reason is that you want the miniDSP to handle all the cross-over functions for your mains and subs (instead of using the filters in your subs), in addition to room EQ. This gives you (and Dirac) much more flexibility and control in setting up your subs (and mains) and to integrate them together. By offloading all the bass duties off your mains onto your subs, you will get cleaner sound at higher SPL from your mains.
 
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Pirateboy

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This is the recommended configuration per miniDSP's application notes.
https://www.minidsp.com/applications/digital-room-correction/ddrc-24-for-2-1-system
View attachment 55804

You'll want to put the miniDSP after your phono stage/pre-amp. The reason is that you want the miniDSP to handle all the cross-over functions for your mains and subs (instead of using the filters in your subs), in addition to room EQ. This gives you (and Dirac) much more flexibility and control in setting up your subs (and mains) and to integrate them together. By offloading all the bass duties off your mains onto your subs, you will get cleaner sound at higher SPL from your mains.

Thanks.
Do both my subs need to connect to the DSP then?
 

NTK

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It is the preferred (or more flexible) way. It allows individual control (EQ, time delay, etc.) of each sub. However, I don't know if the version of Dirac in the DDRC-24 can automatically setup two separate sub channels, or just treat them as a single channel. If it does not, you may setup them up manually, but setting up multiple sub channels (as in sound field management, see an intro in the link below) is a pretty advanced and technical topic.
https://www.audioholics.com/room-ac...i-sub-sfm/the-birth-of-sound-field-management
 
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Pirateboy

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It is the preferred (or more flexible) way. It allows individual control (EQ, time delay, etc.) of each sub. However, I don't know if the version of Dirac in the DDRC-24 can automatically setup two separate sub channels, or just treat them as a single channel. If it does not, you may setup them up manually, but setting up multiple sub channels (as in sound field management, see an intro in the link below) is a pretty advanced and technical topic.
https://www.audioholics.com/room-ac...i-sub-sfm/the-birth-of-sound-field-management
I'll have to have a bit more of a read up & get in touch with them by the looks of things.
Is there anything similarly priced that would be an alternative?
 

NTK

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Forgot to mention that the vast majority of multiple sub users do not set up their subs in a sound field management style arrangement. It is too complicated (or too costly to get the Harman system). But you should still be able to very satisfactory results by placing two identical subs as shown below (source). This requires only 1 sub channel and you may use an y-splitter to let the subs share the same signal.
(Additional references: https://www.harman.com/documents/multsubs_0.pdf , https://www.minidsp.com/applications/home-theater-tuning/tuning-multiple-subs )
C4.jpg


The miniDSP devices offer a lot for pretty decent prices. The miniDSP 2x4HD is the same hardware if you can forgo Dirac Live and use REW for measurements and generate the EQ parameters (Dirac Live is available as an upgrade if you want it later). The Behringer DCX2496 may be considered as an alternative but it isn't cheaper (and require more manual work).
 
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Pirateboy

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Forgot to mention that the vast majority of multiple sub users do not set up their subs in a sound field management style arrangement. It is too complicated (or too costly to get the Harman system). But you should still be able to very satisfactory results by placing two identical subs as shown below (source). This requires only 1 sub channel and you may use an y-splitter to let the subs share the same signal.
(Additional references: https://www.harman.com/documents/multsubs_0.pdf , https://www.minidsp.com/applications/home-theater-tuning/tuning-multiple-subs )
View attachment 55831

The miniDSP devices offer a lot for pretty decent prices. The miniDSP 2x4HD is the same hardware if you can forgo Dirac Live and use REW for measurements and generate the EQ parameters (Dirac Live is available as an upgrade if you want it later). The Behringer DCX2496 may be considered as an alternative but it isn't cheaper (and require more manual work).

That sounds like a good idea just to get a feel for it. I'm almost thinking of getting rid of my preamp & getting the SHD so it can do the lot. I mainly listen to vinyl so the pinnacle of dacs isn't a priority. It's not like I'm going on holiday anytime soon with what's going on either. Whatever I get those subs need taming a little bit. One minute they sound amazing, can't tell they're there, the next minute the light shades are rattling! I could take use my dac/streamer & get some bookshelves for the dining room instead of using the awful Bluetooth speaker we've got in there at the mo.
Can the SHD replace a preamp adequately?
 

Dj7675

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That sounds like a good idea just to get a feel for it. I'm almost thinking of getting rid of my preamp & getting the SHD so it can do the lot. I mainly listen to vinyl so the pinnacle of dacs isn't a priority. It's not like I'm going on holiday anytime soon with what's going on either. Whatever I get those subs need taming a little bit. One minute they sound amazing, can't tell they're there, the next minute the light shades are rattling! I could take use my dac/streamer & get some bookshelves for the dining room instead of using the awful Bluetooth speaker we've got in there at the mo.
Can the SHD replace a preamp adequately?
Yes it can replace your preamp. I have also had the DDRC24 as well. If replacing your preamp is possible, I would recommend going straight to the SHD. It does so much, and does it very well. The minidsp ddrc24 form factor always made things a bit of a mess which was another nice benefit Of the SHD.
 
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Pirateboy

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Yes it can replace your preamp. I have also had the DDRC24 as well. If replacing your preamp is possible, I would recommend going straight to the SHD. It does so much, and does it very well. The minidsp ddrc24 form factor always made things a bit of a mess which was another nice benefit Of the SHD.

I've emailed them about shipping to the UK & it's $32. Works our £1005 with shipping. As far I can see it's 3.5% inmport tax, £35, plus 20% VAT so about £1213 delivered unless I've really messed up? I'm going to have a proper think about it over the weekend.
 

bluefuzz

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I'm almost thinking of getting rid of my preamp & getting the SHD so it can do the lot. I mainly listen to vinyl so the pinnacle of dacs isn't a priority.
The NAD C658 may be a better option then. Dirac on the SHD is only two channel whereas the C658 has separate sub channels in Dirac which adds flexibility.
 

Dj7675

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The NAD C658 may be a better option then. Dirac on the SHD is only two channel whereas the C658 has separate sub channels in Dirac which adds flexibility.
SHD has 4 channels, so it can do a 2.2 system with Dirac. The C658 does have a built in phono input, however if your existing preamp is providinig the phono input. The C658 also will be less of a learning curve I would think as well, as it is a more traditional preamp type of device. There is a little learning curve with the SHD. The C658 has about every feature you would want. The only ding on it is it just doesn’t measure well and some have had some issues with it.
 

Jake's Dad

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I'll have to have a bit more of a read up & get in touch with them by the looks of things.
Is there anything similarly priced that would be an alternative?

Check out the DSPeaker Antimode 2.0. It only does EQ up to about 300hz rather than full range, but of course the lower frequencies are typically the only ones that require correction. Considerably cheaper too, especially if you can find one in the aftermarket. 725 Euro. I've been super pleased with mine for about 4 years. Cheers, Alex
 

bluefuzz

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SHD has 4 channels, so it can do a 2.2 system with Dirac.
I don't have an SHD but from what I understand from the MiniDSP site is that the SHD can do a two channel crossover in stereo or 2 mains + 2 subs but the Dirac implementation is still only two channels whatever. There is no separate Dirac group for the subs like on the C658. So the subs would be measured as if they are part of the mains. Whether that makes a lot of difference I couldn't say.
The only ding on it is it just doesn’t measure well and some have had some issues with it.
Well, the only measurement we have is Amir's of an obviously broken unit. I am reserving judgement on that until a fully working unit can be tested ...
 

TimW

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Well, the only measurement we have is Amir's of an obviously broken unit. I am reserving judgement on that until a fully working unit can be tested ...

The SINAD measurement Amir took is actually better than NAD's THD spec which is <0.005%. I wouldn't expect a unit with working SPDIF inputs to measure any better in that regard. The comments from owners with other serious issues with their units makes me hesitate to recommend this product.
 

bluefuzz

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The SINAD measurement Amir took is actually better than NAD's THD spec which is <0.005%.
Yes, I know. And since OP is mainly playing vinyl it's more than adequate. Can anyone really hear the difference between 0.005% and 0.0005% ?
I wouldn't expect a unit with working SPDIF inputs to measure any better in that regard.
Nor would I to be honest, but a broken unit is a broken unit ...
The comments from owners with other serious issues with their units makes me hesitate to recommend this product.
There is a handful of very vocal users that have apparently had some issues – we really don't know how many of them are misconfigurations, user error or actual issues with the device. There are equally many users (including myself) who are perfectly happy with the C658.
 

Dj7675

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I don't have an SHD but from what I understand from the MiniDSP site is that the SHD can do a two channel crossover in stereo or 2 mains + 2 subs but the Dirac implementation is still only two channels whatever. There is no separate Dirac group for the subs like on the C658. So the subs would be measured as if they are part of the mains. Whether that makes a lot of difference I couldn't say.
Thanks for your comment. I too have no idea if it matters but it is correct. I always thought it was odd but in use it doesn't seem to matter in measurements and how it sounds to me as it sounds great in a 2.1 system I am using.
 
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Pirateboy

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I decided to get rid of my preamp & go for the SHD instead. I wasn't really a huge fan of my pre & was mainly putting my phono stage direct to my monos. I've got 2 phono stages, an EAR 834 & a Grahame Slee Accession, both with volume control & both sounded better skipping the preamp. They sound very different but I love the pair of them depending on my mood. Having a pre amp with a remote is much more convenient though! Anyway my current dac will be going into a little system in the dining room later in the year & I'll use the one on the SHD, which should be plenty for my needs. I ordered direct from minidsp for £1026 shipped with UMIK. I'll probably be stung a little for import tax & VAT but it'll still work out much cheaper than the UK suppliers, which are £1699 with the UMIK. Should be here within 2 weeks. I know it'll be a learning curve but there's some great advice on their forums & I can't wait to try it out.
Thanks for all your help.
 

LBec

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Just got the $29 DSP from Parts Express (DSP + input/output board). Not sure how good it is, looks a lot like the Sure board but with a Dayton Audio label. The THD specs from Sure look ok until you get above around 5-10kHz. Probably will get the programing board for another few dollars.

For now just looking at it as a toy to learn about DSPs and programing them, it is based on the Analog Devices ADAU1701 DSP chip.
 
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