Hypex DLCP (DSP) with 6 Channel UcD Amp Project.

[Ali Tait]

Good news.

[Qwin]

I've now had a good listen to the DLCP and put my analogue active crossover back in the system, I think that says it all!

The DLCP just doesn't cut it, not bad on digital sources, but my analogue crossover is better.
With my analogue (vinyl) source it is way behind.

Just too soft and rounded off for my taste, with a reduction in bass weight.

I didn't even get to try room correction etc. In a like for like set of basic crossover filters, without any EQ the basic tonality from both set ups was similar, but the digital just sounds flat and lifeless in comparison. Some folks might see it as an acceptable sound, especially if not using vinyl. I feel I have definitely stepped backward and I'm looking to move forward. I tried moving the crossover points and changing the slopes, but they were pretty much optimum where they were. The DLCP just has a signature sound that will not change with minor tweaking and is fundamental to the product.

Music used:
Vinyl
Grace Jones-Night Clubbing
Yello-The Race-45rpm
"Tracey Chapman"
Joni Michell-Hissing of Summer Lawns
London Grammar-If You Wait-45rpm
Jo Jackson-Night & Day
Dire Straights-Love Over Gold

CD
Malia-Convergence
Kenny Burrell-Midnight Blue
Web Sisters-Savages
Otis Taylor-Collection
Laura Mvula-Sing to the Moon
OMD-English Electric
Calexico-The Black Light
Gregory Porter-Take me to the Alley
Sea Sick Steve-Walkin Man

Streamed (Deezer)
Alison Moyet-Other
"America"
B B King-Lets do the Boogie
Kraftwerk-Minimum Maximum (Live)
Yello-One Second

I will mount the DLCP in a case, it will now be relegated to a development tool. When I get the measuring sorted, I will use it to finalise my analogue active set up. I need to reduce the rising response of the ribbon tweeter, a 5dB hump between 7kHz and 24kHz, the DLCP proved very effective at quickly trying this and it was a noticeable improvement. I used the plot from the driver spec sheet for the parameters, measuring real world combined driver response, should give even better results. I've been using the passive filter for the tweeter and it dealt with the hump, but I want to be fully active in the final version, even with the DLCP the ribbon tweeter sounded nicer active (flattened).

So I tried it and it didn't work as well as I had hoped, moving on to plan B.

I've now heard the DLCP and several mini-DSP offerings and not liked any of them. Gordon (Halfway tree) uses software based active filters through good quality stand alone ADC and DAC's. His results are a major step up over these one box solutions and I see this as the future for high end DSP.

[Qwin]

I've been very disappointed by the sound quality of the DLCP, light in the bass, soft and woolly mid range, not good at all. Double checked everything, nothing wrong with the way things were connected or with the filters I created, which are exactly the same as the analogue ones.
I re-read some of the threads on the diyaudio forum and folks were very pleased with the sound, so something wasn't right. I thought about the power supply, I was using the Aux output from one of Hypex's amplifier SMPS, which is an option suggested by Hypex. I thought about buying their dedicated SMPS for the DLCP which outputs the main dual rail voltage but also produces the single 8v standby voltage. I was very surprised when I read the spec sheet for this supply:

"This switch mode power supply is specially designed to be used in mixed signal applications such as DSP and audio applications requiring a single low voltage output for powering the digital parts of the circuit and both a positive and negative output rail for powering the analogue circuitry."

So the single 8v output may not be just for the standby function, I had used a cheap switching supply about 25x35mm for this, you can see it front left in the previous picture (post #17), as I presumed from the blurb, that it was not in the audio path. I decided to buy the dedicated supply.



Didn't take long to swap out the Amp SMPS for the dedicated supply.
What a difference, instantly more drive, solidity in the bass and crisper more transparent mid range, this is more like it.
Still slightly better with digital rather than analogue sources, but not a lot in it, much much better.
Hypex are known for minimal instructions, you don't actually get any and have to use the sparse information from the on-line spec sheets, which are great at detailing pin outs etc, but say little about what options you have, if straying from using an all hypex solution, (PSU etc) if you do your pretty much on your own. But to be fair, I have found them good at answering emailed questions relating to my build.

So, I'm a much happier bunny, after a few hours of running, this is sounding very good indeed.
I need to give this careful consideration now, as to whether the performance is better than my analogue active set up, enough to persuade me to enter stage two of the project and purchase six amp modules. These would form a Digital Pre/DSP/Power Amp's in one case, as detailed earlier.

I think I need some extra ears now to give a second opinion on this.

[Qwin]

Still tinkering with this as well as other projects.

I'm at a bit of a crossroad situation...... I need to optimize the sound of the Hypex DLCP before making my final choice of using a Digital or Analogue active crossover.

I'm taking my time over this as there is a lot to take in and learn. If your drivers are reasonably well matched, its easy to get a fairly good sound out of some basic filters quickly thrown together. To get the best out of your driver combination, is another matter and I've gone about as far as I can without measuring what is happening.

To this end, I have just purchased a Focusrite 2i2 USB interface and I'm waiting on a Dayton EMM-6 mic from the States. The mic has been purchased from and calibrated by Cross-Spectrum Labs, to be accurate from 5Hz to 25kHz. All this technical malarkey is a big sideways step from enjoying my music, but it's my hobby and a necessary evil if I want to build something that will compete with commercial offerings well beyond my price point.

One of the best features of the Hypex system, is that their DSP software is also the analysis software and it all works together in a single interface.

The easiest way of explaining this principle is with a screen shot from their very minimal manual.



The Red trace is the measured and imported response, you can work on an individual channel (driver) or the summed response for all channels (drivers).
To add a filter, you click on the approximate position you want it (Green Dot), then in the main menu select the type of filter and adjust the frequency and +/- dB figures etc in the dialog boxes, to the exact ones required. This creates a filter and it's displayed as the Cyan trace. The Orange trace is the programs prediction of how this filter will effect the imported response. Users have reported a very similar measured response, to that which was predicted. You can add multiple filters/adjust/delete as required, it's quite a nice interface and fairly easy to pick up, through trial and error.

It may not have all the bells and whistles of something as powerful as REW, no waterfall display for instance, but you do get Magnitude, Impulse and Step screens to work with. It's aimed at the DIY market, not at Audio Engineers and its feature set and interface have been designed with that in mind.

It's a very useful tool, but Hypex make the point that they expect you to have a basic understanding of some of the audio science behind it all. I would add that, just as owning a CAD system will not automatically turn you into a mechanical engineer, using this type of software does not make you an audio engineer, with the knowledge of how to interpret and respond to the displayed results. That said, with a bit of reading, from their manual and around the forums, you can gain enough knowledge to produce very satisfying results.

I need to put some of this to use now.

[Qwin]

.
I have taken my Yamaha NS1000M Project about as far as I can with my semi active (analogue) solution and I am very pleased with the results.

I feel another speaker project coming on, maybe my ultimate 3-way. The DLCP will be the ideal tool to help me design the crossover, but it's about time I put it in a case, so I got an appropriate off the shelf item from HiFi2000.




I had previously worked on a layout, but I decided not to build in any amplification this time and leave that external.





The fixed block of controls required some pretty accurate drilling to guarantee the push buttons didn't stick. I made an Acrylic window for the display to make it tidy and keep the dust off the screen.





The business end was just as tricky to make, as the top row of inputs is a fixed assembly on a PCB, so no room for error when making the apertures. Being a Hypex unit the 6 outputs are all balanced to match their Amp modules inputs, but they will work with single ended using adapter connectors or leads. I used my usual traffic light system for identification. Red for Tweeters, Amber for Mids and Green for Bass. So it's ready for action.

[Firebottle]

Nice job Ken. Excellent work with the holes

[Ianmac]

Ken
Ive not been on the forum for over a year due to a health issue. Im getting slowly back to normal and looking at using the new Hypex Fusion Plate amp to dip my toe into actives.
I looked at the DLCP solution before my illness with a view to modding my ATC SCM40's put pulled back re difficulty in getting information on setting up the filters, a free space to set up the LS ( outside in the garden was my best option), the possibility of devaluing my ATC's and the overall cost.
Im having to donate most of the gear from my 2nd system to my son and will be left with a pair of Kef reference 1point2s (3way dual concentric tweeter / mid and ported bass driver)
Fusion 3 way F123 100w tweet + 125 watt mid & bass or F253 100w tweet + 250 watt mid & bass are possible options. Like you I am finding the lack of info on the hypex software an issue and the correct method of using the varios filters a problem.
I did have a calibrated mike two years ago but unforunately sold it. I have a focusrite 2i2 and a separate mike pre.
I dont want to jump into spending on amps without a much better understanding of what Im doing.
Can i ask how you are getting on with your DCLp project particularly the results from using your analogue input as I'm not too keen on the A to D conversion required.
Many thanks
Ian

[Qwin]

Hi Ian
The Analogue to Digital conversion on all these one box DSP solutions is not good enough, regardless of who the manufacturer is, Hypex is better than miniDSP, but still not good enough. Analogue from a turntable will definitely take a large step back in quality. They concentrate on the Digital to Analogue side and you can get great results if you only use digital sources.

I completed the DLCP as shown above, nice tidy, self contained unit, now in a case, but uses XLR balanced outs to plug into external amplification. I use this purely for crossover development and it's not part of my audio set up.

For my 3-way speakers I now use an (Analogue) active filter (Rod Elliott's) which works at 500Hz, the bass amp/driver is fed the <500Hz and >500Hz is supplied to a separate amp feeding a simplified Passive for mid/tweeter, crossing at 6kHz. By using the Active as a pre filter, the Midrange does not need a band pass, which simplifies the circuit and removes the need for the big value series capacitor, that most 3-way passive circuits use on the mid driver. You end up with a simple 2-way passive circuit.

This set up works for me, and the TT sounds great through it.

You can follow it here, from "A Fresh Start" at Thumb Yam_38 onwards. http://www.jkwynn.co.uk/Yam_HTML/Yam_Thumbs.html

The basic advice on filter design, in the DCLP manual is all I found, so it was trial and error after that. As I now use DLCP just to determine the values for a passive or simple analogue active circuit, I tend to be using simple 12 or 24dB/Octive LR filters and experiment to find the best crossover points using these. The built in measuring and predictive software help with this a lot. I also use a Focusrite 2i2 with a calibrated mike from Cross Spectrum Labs.

[Ianmac]

Ken
Thanks for the feedback. I note your comment re the A to D issue I suspected.
Ill have to give this more thought.
Having built a quality phono pre Ive got my techie sounding good and use it a lot with this system (Benchmark Ncore's KEF)

In the meantime ill look for a S/H Benchmark DAC 1 hdr and use a Cyrus amp I have to drive my KEFs
many thanks
Ian

[Qwin]

An alternative approach is to use your DLCP for digital only, direct from your sources and buy a separate, quality ADC and attach your TT to that and feed the digital output into the DLCP.
Mytek etc make such products in two channel and multi channel form like the Stereo 192 here: https://mytekdigital.com/professiona...tereo-192-adc/

A big favorite amongst studio users is the Burl Audio B2 Bomber, many producers swear by it for the analogue sound it produces. Several interviews reguarding this on youtube. But its over £2.5k see here: https://sxpro.co.uk/burl-b2-bomber-a...SABEgJ_zPD_BwE

I made an offer for a second hand B2 on gear slutz, but was outbid.