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Achieving High Fidelity Sound

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 2021 at 9:39pm
Yes, selling both my headphones. The Alpair 11MS will sound utterly incredible nearfield with some EQ. If this mono-suspension driver existed several years ago, I would have stopped using headphones ages ago. I'm so glad I kept the Proprius; they perform wonderfully for this application. Been listening to a lot of piano music to judge unevenness in dB SPL of various regions/octaves of the scale.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 04 Jul 2021 at 9:23pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2021 at 11:47pm
Going back several years to about 2015, I used the Mark Audio Alpair 12PW and 7P for a while but ended up selling them after deciding to use my AKG K1000 exclusively, as I did not have enough desk space for speakers at the time, due to living in a box room. 

The highlight of the 12PW/7P combo was a very wide bandwidth (very deep bass extension) and a neutral tonality with quite a flat on-axis frequency response. I remember comparing them on cardboard open baffle to my K1000 and the speakers sounded similar in frequency balance but better in spatial abilities. I was fixated on full-range single drivers then so I sold the speakers. I have bought the combo again today because I want to compare them to MySphere before I sell it. I had to buy a second-hand pair of 7P as they are no longer manufactured. The price of the 12PW has risen quite a bit too. £350 spent and just waiting for their arrival. I intend to eventually combine the 11MS and 12PW and sell the 7P on when I sort out EQ. Need to do some comparisons before parting with the best headphone reference money can buy and liberating the funds for more Slee goodies.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 19 Oct 2021 at 8:45pm

I have spent many months pondering the most effective ways to optimize a PC for audio reproduction. My conclusions have been focussed on good PCB design, quality power delivery, solid state storage and plug-in boards to reduce numbers of cables. I have moved away from the use of laptops as even though they are a compact solution and are easy to plug into quality power or use batteries with, I like being able to customize parts. With a laptop platform, a lot of design decisions are already made for you and cannot be easily changed without dissecting the laptop if there is a particular component that you want to change. Desktop have more freedom to add hardware like PCIe cards and remove low quality or noise-generating components readily. But desktop PCs typically use the ATX-standard for power delivery, which has some additional complexity if trying to implement non-ATX power supplies.

So what is the best solution? A streamer or low-power single board computer? Well dedicated streamers can be very expensive (read: overpriced) and can be too specific in purpose lacking the versatility, flexibility and processing power of a PC. SBCs can be economically priced yet often lack CPU data processing power for multi-use purposes and tend to lack high quality graphics processing as well. Media is often audio-video, not just audio. Dedicated PCIe graphics cards for PC can be very large, expensive to buy and to operate (high power consumption), noise-generating and since the cryptocurrency-pandemic combination, unobtainable/overpriced due to global chip shortages.

So what next? If I've ruled out laptops, large desktops and dedicated devices and low-power SBCs, I need to look at something industrial. Something that combines enough processing power with quality graphics, hardware expandability, power simplicity and ideally a pretty small form factor. The most economical in terms of cost would be something like an industrial mini-ITX board from a brand like AAEON with a straightforward 12V DC power jack input and a sensible choice of processor, to give both capable CPU and iGPU, with a x16 PCIe slot on the board in case I ever wanted to try adding a discrete GPU. I would probably have gone down this route if I hadn't encountered the UP series of embedded industrial boards, which seems to be releasing something that might just fit all of my use criteria.

I have opted for a top spec UP Xtreme i11 in the hope that I will get the most out of a PC for media playback yet still have enough versatility to try new things. I can connect quality 12V power via a simple jack and the power consumption is fairly modest compared to a desktop PC. The nano-ITX size is much smaller than mini-ITX, but has better hardware connectivity and thermal considerations than pico-ITX. Trying to forget how much it cost to buy but I look forward to having a play with it. Shall be buying a quality 12V PSU for it and implementing my PCIe soundcard with its own PSU. A Raspberry Pi compatible 40-pin GPIO sweetens the deal for further learning and the 5G support for cellular data means I’m not solely dependent on wi-fi (my room doesn’t have an Ethernet port).


Already have M.2 NVMe storage and SO-DIMM DDR4 RAM ready from my current mini-PC that I bought last year. Replacing it with this UP board as the power circuit is very electrically noisy, which is audibly transferred into my audio equipment and into noises at the speaker cones. I tried the mini-PC with a different 12V power supply and the noise was unchanged so it is clearly a poorly designed motherboard for audio purposes, especially compared to the quality Taiwanese gaming motherboards that I was using before. It will get me by until the UP board is delivered then I will start to move everything onto the new platform and sell this Chinese mini-PC.

I had/have also been playing with the Mark Audio Alpair 12PW and 7P paper-coned speakers. I fixed them onto cardboard open baffles and I have used them over several weeks. I positioned the drivers as close together on the baffle as physically possible, as shown below.


These speakers have a nice neutral sound but I don't think they sound as promising as what the Alpair 11MS can do, even though the 11MS mono-suspension drivers clearly need some digital EQ to flatten their dB SPL response to something resembling MySphere 3.1's ultra-flat response. I like the single suspension concept for speakers and how it makes the speaker like an oversized headphone driver, with less physical obstruction to its mechanical movement. Sonic qualities like impulse (change in momentum) should be better as less moving mass to accelerate and no pair of suspensions (spider and front surround) working against each other elastically. I am thinking of eventually trying a double-Slee system with two pairs of 11MS on close proximity open baffle with digital parametric EQ for a simple crossover and frequency correction graph. I drew a simple diagram below; the dotted lines/boxes are optional extras for a second system if the one pair of 11MS don't move enough air on their own.



Just a rough first diagram but it allows me to use the corrected speaker response with both analogue and digital sources, minimizing the numbers of conversion steps for each path. If I can get the 11MS sounding as amazing as MySphere 3.1 (hopefully much much better), I will sell the ultra-expensive headphone to fund this dual-speaker system and call it a day. I have already sold all of my other headphones; for the first time in several years, I only own a single headphone. In time, 1 may become 0 if I can no longer justify the invested funds.

P.S The miniDSP NanoDigi looks to be discontinued so I might have to source a used one or find a different solution. I'm not parting with MS 3.1 until I can match its precision with speaker response.


Edited by Ash - 19 Oct 2021 at 9:51pm
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