World mail March 2013 issue
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The Naim NAC-N 172XS we reviewed in our February issue plays high resolution audio files from a memory stick, to give superb digital sound quality, better than CD – and it is easy enough to understand if you are a digit-phobe like Dave Mayer.
ON STREAM I read Noel Keywood’s opinion piece in December’s issue and something suddenly happened ... a cloud of despair and despondency descended over me. I realised after enjoying, buying, messing about with and generally loving hI -fi for 30 years that things had moved on ... not just moved on but actually dramatically changed over the past few years. By this I refer to the ‘download/streaming/tablet/computer' based direction that things have moved towards. Here for me – and I’m sure thousands, possibly millions of others – lies the problem. I simply do not understand it!!! Over the past thirty years since I left school and started earning money I’ve read the mags, visited the hi-fi shows and built and upgraded to a pretty good system of separates that I’m proud of and absolutely love listening to. The most recent purchase was some Kimber Powerkords, so for me I’m just at the tweaking stages. Just as I head towards the finishing line, I look up and realise maybe I’m running in the wrong direction? In the same issue was a letter (‘Library’, page37 from Brian) regarding MP3 downloads/USB sticks that I also found myself scratching my head at ... what is going on? I don’t have a clue what this huge, growing and quite clearly current sector of the market is all about, how it works, the basics of the whole damn thing. Obviously, I blame myself for maybe taking a bit of an ostrich approach (head in the sand) over the years and focussing my reading etc on those reviews, articles that interested me, or were relevant to what I was looking for at the time. I have a PC in an upstairs home office, hI-fI is downstairs in the lounge, don’t own an IPhone or download music. I still buy CDs, funnily enough...am I prehistoric or what!! So what can I do in terms of linking computer audio to traditional hi-fi...and for goodness sake where do I start? My best friend recently mentioned that he was going to buy his first decent high end hI-fI to go with his Linn Keilidh speakers. He asked me what I thought about the Naim Uniti, Linn something or other and Cyrus streamer amongst others. He may as well of been from the Planet Zog, as I hadn’t got a clue what he was on about in terms of performance, facilities, compatibility etc. So can I plead with you as a decent hi-fi mag to put together a ‘beginners guide’ article – feature to the whole streaming/download business. How it works, what to buy, what does what, what you need, how much do you need to spend to get something decent, performance vs separates playing CD or vinyl, what download formats mean, high res, 24/192,USB, ripping, up-sampling 24/96. See what I mean? Please help me and doubtless loads of other hI-fI enthusiasts get at least a little bit more up to speed and re-join the right race!!! Cheers Dave Mayer
I understand where you are coming from Dave and we are discussing such a feature right now. Unfortunately, it is truly a complicated subject. Although digital is 'perfect' in theory, in real life many products are far from perfect. There is a divide between the lacklustre sound of budget portable audio, nowadays an iPod playing music (128kbps AAC) downloaded from iTunes, through headphones, and what can be achieved by improving file quality and channeling the result through a decent hi-fi, such as you likely own already. You can read about this again further on, where Sonos say clearly CD quality is good enough for them (as it is for Samsung, Sony, Apple et al with their tablets) and what is taking place elsewhere – see our Astell&Kern AK100 review. If you have a computer upstairs you can buy and download files from HDtracks, load them onto a memory stick (I use LaCie Whizkeys) and play them from any media player from Cambridge Audio (e.g. StreamMagic 6), Naim (NAC-N 172XS) and a host of others.
La Cie Whizkey high speed memory with aluminium screening and no LED, lowering current draw.
Note I say nothing about ethernet, wi-fi, Bluetooth and all that (comms systems), nor about Macs, music players like Audirvana, file convertors like XLD, or any other menu adorned software headache. I don't mention internet radio either. Nor do I mention Spotify or iTunes. You can usefully keep away from all this as a newbie and are better off for doing so. Download high definition files and play them through high definition audio players. The benefit is stunning audio quality through the hi-fi system you own and use today. No ethernet cables, no router menus, no DNLA menus, no pairing and no stuttering. No MP3 either! Just lovely sound quality, better than CD. The drawback is cost. High definition album downloads cost as much as quality vinyl, or Blu-ray. The hardware is expensive too: up to £2k or so for a decent media player. But this is a one-off expense that, if you ensure 24/192 capability, should last many years. I hope this gets you off to a flying start without suffering a severe headache on the way! More lurid digital detail will coming your way soon from our pages! NK
Cambridge StreamMagic 6 plays high resolution digital music files from a memory stick.
FRENCH QUESTION As I live in the depth of South West France - think mid-Devon circa 1950s – it’s difficult for me to audition hi-fi equipment, so I turn to you for expert advice and unbiased ears! I’ve recently had my Linn LP12 upgraded by Inspire hi-fi, who also added an Inspire X100 arm and Audio Technica AT33EV cartridge, all influenced by your fine team – and a great improvement I might add. I now almost exclusively listen via the vinyl medium, digital sources definitely taking second place, especially now that so much great music is available on LP. Your excellent vinyl section and of course fascinating letters giving me the most pleasure. My system, apart from the aforementioned, is all Naim – CD5i player, NAC 62 pre-amp, two Hi-CAP power supplies and a pair of SBLs powered by two NAP 250s bi-amped using a SNAXO 2-4 active crossover. All being supported by a Naim Fraim rack. The speaker leads are also by Naim. You may deduce that I love the Naim sound and although that’s true I came about using their products more by accident than by design. It all began back in ‘93 when I bought the pre and power amps and a power supply from a friend and built up from there. I do find the sound of my system with certain recordings on the bright side and taking into account that having been a professional drummer for 30+ years I’m pretty used to a bit of attack in the high-mid frequencies! And unlike my wife who’s hearing is in better shape, I don’t feel the need to cover my ears when a particularly ‘forward’ sounding recording is being played, but I do find myself wincing sometimes even at medium volume settings! I recently bought a copy of the re-issued Sergeant Peppers album and found it almost unlistenable, it was so hard and ‘middly’ sounding – then I noticed it was remastered from a digital source. So much for vinyl being analogue! I have to say that due to domestic considerations my listening room set up is not ideal (15ft x 19ft with 91⁄2ft ceiling with the SBLs firing across the width – the floor is tiled with rugs. But when I had the same system back in England, in a much larger room, the sound parameters were much the same. I’m looking at two areas of improvement and would be grateful for any suggestions; a valve phono stage, as I understand this will add ‘warmth’ and seems to be an economical way for me to get a valve sound without having to change the power amps. You speak highly of the Icon Audio PS3. Or maybe if I went for a valve pre-amp (like the Icon Audio LA4 MkII) in place of the NAC62 it might make me re-evaluate my CD collection and save me some funds towards a pair of speakers – the next area I think could be improved. I have a nostalgic memory of listening to a large pair of Tannoys at a friends house and falling in love with the sound – smooth, warm with great bass. I’m interested in the DC10s although my room may be too small for them, but I’m looking for that bass extension. I listen mainly to rock and some jazz. My budget would be around £2000 for the phono stage or preamp and £6000 for the speakers. Any suggestions would be gratefully received. Best wishes, Boris Williams
Tannoy DC10T has a lovely smooth sound, deep insight and very powerful bass – great for a Rock drummer like Boris Williams.
Hi Boris. I think your suggestions make a lot of sense. The NAC 62 is getting on a bit and has a reputation for sounding rather dry and soulless. Everyone who tries a valve preamp with a Naim power amp remarks about the peculiar symbiosis between them and you will get a fuller sound. This is a great way to build a hybrid amplifier in effect and the Icon Audio LA4 MkII you suggest is a good choice. But you will then need an additional phono stage. If you mostly use vinyl, you could run an Icon Audio PS3 valve phono stage direct into the Naim, because it has plenty of gain and a volume control. Insert a passive preamp like the Creek OBH-22 to play CD as well, or perhaps Icon Audio’s passive preamp. The latter may be most convenient, as it’s a single order and delivery for you, perhaps by a Deux Chevaux fourgonnette, along with the Armagnac! Well, it’s better than having a box thrown at you from the back of a Transit, as happens to us in London. Tannoys sound like the loudspeaker for you. Any self respecting Rock drummer will understand and enjoy a Tannoy. And just as you say they are smooth and have strong bass. The DC10 can be tamed with foam bungs that now come supplied and it may suit your room, which at 19ft is a healthy size. They worked well in our 24ft listening room, but only with foam bungs, unless you like really vast bass. The DC10T had tremendous insight too, likely due to Cryogenic treatment of the crossover. You could perhaps go for a DC8T instead as these nowadays come in well under your budget. Or, just to confuse the issue a little further, you may want to wait and save for a new super-tuned DC10 Tannoy have been working on for some time. It seems this loudspeaker is popular in the Japanese market, and they have demanded even more from it! The local Deux Chevaux will struggle with a pair of these, however. You’ll need a camion. NK
A STEP UP While you’ve occasionally highlighted the value of employing a step-up transformer when using a MC cartridge, as far as I’m aware, you’ve only actually reviewed one from Music First Audio in the last few years. This one review was enough to convince me, however, and I ventured to explore the world of step-ups myself albeit at a lower price level. After considering several from Audio Note, Ortofon and Rothwell, I decided to purchase the Icon Audio MCTX as it’s offered at a good price, is made in England and uses the same transformers as used in their well reviewed PS3 phono stage. Well, I must say that the MCTX has been a revelation and has lifted my vinyl set-up significantly over my CD/DAC set-up. As I’m sure a lot of your readers would similarly benefit, can I suggest that you undertake a group test of step-up transformers (maybe including Audio Note’s DIY kit) sometime soon? Regards. Rob Murphy
The MCTX step-up transformer for moving coil cartridges allows them to be used with an MM phono stage. It "has been a revelation" says Rob Murphy.
Hi Rob. Tantalisingly, you do not tell us what cartridge you are using, nor before and after conditions. Were you using an MM cartridge and have changed to MC? Or an MC stage and you have switched to using MM with the new transformers? A good transformer, potted in a mu-metal screening case to shield against hum and noise, is almost a magic experience. But then it would be, because this is the only way you can tap into the electrical power produced by an MC cartridge. Input transformers give less noise and a purer sound than an amplification stage, transistor or valve. You make a good point that there are now increasing numbers of such transformers coming to market, allowing Moving Coil cartridges to feed a Moving Magnet phono input. We will being taking a close look soon. NK DIGITAL TODAY Just read your Sonos review in the October edition (takes a while to get to Oz). As a Sonos owner, I have a big issue in that although they support 24/96, it is limited to only 16/44 for Flac. This is a terrible situation in 2012. Downloads of Flac 24/96 are commonplace today and Sonos should do something about this restriction if they want to be taken as a serious streaming player. I have a Connect feeding a Bryston DAC and all my music is converted to Flac 16/44. The CDs and LPs play pretty well this way and it is so convenient. Unfortunately I have to play my 24/96 files through my MacBook Pro which is very annoying. I’ve also recently obtained a Furutech ADL Esprit so I can convert my LPs to 24/96. Now I am currently evaluating other streaming products to fulfil my requirements and I wouldn’t recommend Sonos to anyone with serious hi-fi intentions. Before I purchase something else, can you approach Sonos as to the future of Flac 24/96 as they haven’t replied to my request? This would be highly appreciated by me and I would think, hundreds of other Sonos owners. Peter Deitz Sydney Australia
SONOS REPLY - We believe the Sonos user experience delivers the best balance between hi-fi sound, rock-solid wireless and ease of use. We currently support uncompressed audio format like Apple Lossless, WAV or FLAC for your music library and whilst we continue to evaluate new music formats, we don’t have immediate plans to support resolutions beyond CD quality. Sonos
The Sonos system is restricted to 16/44 FLAC, says Peter Deitz, "a terrible situation in 2012".
As you can gather from my review of the Samsung tablet this month, there is a strict dividing line between two industries here and two outlooks: one sees high resolution digital (e.g. 24/192) as where we are going, the other is happy with ‘CD quality’. Most current-idiom ‘audio players’ aimed at the computer generation (shall we say) see CD quality as more than good enough and this includes all tablets and portable audio players. CD quality is a simple description that everyone understands, even those who have little understanding of audio quality – and it is good enough for them. This also embraces compressed music (MP3, WMA, AAC etc). There are justifications for this. When signals whizz through the air there is usually a data rate limitation. By this I mean specifically Wi-Fi links suffer data rate reduction at distance and cannot support high resolution audio that runs at up to 9Mbps, compared to 320kbps (x36 slower) for a typical compressed audio stream. Bluetooth runs at this rate too, even though it claims to be ‘CD quality’ (it is a compressed). Wired links have no such limitation. Also, where headphones are concerned higher quality audio may well be superfluous, since headphone amplifiers are noisy beasts. Unfortunately, companies working in this idiom, like Sonos, march to this beat. My prediction here is that it will all change quickly when a big player like Apple suddenly decides to market a high resolution player on the basis that ‘it puts you in the studio’. Then everyone else will have to scramble to keep up and better wireless links may appear.
The AK100 portable high resolution player has a Mastering Quality folder on-board. for 24/96 music files. Will Apple produce a high resolution iPod like this?
Studios and the hi-fi business see it all differently of course, and more traditionally too. They both work to the notion of ultimate quality and, happily, this is now becoming available to us all, as the Astell & Kern AK100 I review in this issue shows so dramatically. Companies like Naim and Cambridge Audio are making quality 24/192 capable products that chew high resolution files with relish. So it’s time to re-align I would suggest Peter. Modern high resolution audio players don’t cost the earth and they don’t come from Sonos either. NK REFERENCE UPGRADE Your magazine often features older equipment and also has some elements of DIY so I would like to ask a question and see if I can get a little help. After a recent listening session organised by a friend I was able to hear a pair of KEF 103 Reference (original 1976/77 model). I really liked the sound of these and had not owned a proper sealed baffle speaker for a very long time. So like many here I did what we all do and scoured the second hand sales and finally eBay. By luck I found a pair and got them for the very good price (in my opinion) of £84. I have now collected them and put them in my front room for use with my TV and they sound as good there as I remembered they did originally. They also have the advantage of being able to work close to the wall making them more domestically acceptable . However a little online research and some very welcome help from KEF has shown that the crossover is all electrolytic caps which after about 35 years it is very likely they will have dried out and possibly even changed there values. I am looking to replace with polypropylene film items and will also take the opportunity to replace the internal speaker wire with something a little better .
KEF Reference 103 loudspeaker. "I really liked the sound of these" says Andrew McBride.
Now it is almost certain that the new caps will be more electrically efficient than the originals and the replacements will then change the Q of the speaker. I am told it is possible to add a resistor in series to the HF unit which should adjust the Q back to were it was and about 150 R is the normal value to start with. As I do not have anyway of measuring is there any advice you could give on this ? I do not want to change the sound of these units too much as the original sound was what attracted me too them in the first place but if the changes can perhaps add a little transparency and bring them back closer to the original spec then it would be useful. When I removed the driver front mounting plate to view the Crossover it had been sealed with some form of self adhesive foam strip but this had long since dried out and perished can you advise on anywhere that could supply a replacement or alternative strip seal? I have included a copy of the original KEF circuit diagram so that you have the details hope this will help . Regards Andrew McBride
KEF Reference 3 crossover circuit diagram, drawn 1975.
Restoring the KEFs raises some interesting issues. The drawing you sent, dated March 1975 and drawn by hand no less, shows large(ish) value capacitors that are physically quite small and these are likely Alcaps, bi-polar electrolytics recognisable by their black case with red end caps. They do not have a wet electrolyte, instead using a metallised polymer film, so should not dry out. However, other ageing processes may well occur and, looking at Alcap product info for ESR, or Effective Series Resistance, I see it carefully isn’t stated, an equation having DF as a variable whilst the DF equation has ESR as a variable, meaning you cannot solve either! This makes me suspect the capacitors may well have quite a high ESR even when new and I will presume 1 Ohm. Inserting new film capacitors will raise tweeter output by 3dB or so. But the original ESR is likely to have been compensated for in the design, so you will have to re-insert it by adding 2 Ohms in series with the T52 tweeter. This is a very approximate figure, because I have made some gross assumptions, but it gives some idea of what the issues are, and their magnitude. The way I would tackle this is to get six 1 Ohm, carbon film resistors of 0.5 or 1 Watt, and connect them in series with the tweeter until I got the result I wanted. Start with one resistor of 1 Ohm. If it makes the sound too dull, then connect the other resistors progressively in parallel. If it is insufficient, then connect the other resistors progressively in series. You could also consider removing the crossover altogether, placing it outside the box. I would leave the original in place and re-build a new external crossover, with the inductors further apart (but still at right angles) and on separate bass and treble boards. The assembly can go into a solid plastic or aluminium case that sits on the floor. Do not solder leads onto the drive units as you may well unsolder connecting wires to the tags. I think you can lead cables out through the ports. Leaving the old crossovers in place allows the speakers to be returned to original condition if desired, but if you think this unlikely you could use the original inductors. If you get new inductors make sure they have ferrite cores like the originals, so their d.c. resistance stays roughly the same. Do not use air cores, for this reason. There is quite a lot of fun you can have here, experimenting with external crossovers that can be hacked about. New crossovers with better components will make a big improvement and you can tweak values until you get the sound balance you want. NK
ACTIVE CROSSOVERS I very much enjoyed reading Peter Comeau’s musings a while back concerning various loudspeaker design concepts, and I thought I would share some of my experiences on the path I have chosen to follow – which has been fun and rewarding in equal measure. Having tried various types of loudspeakers over the years, from run-of-the-mill bass reflex designs, to full range horn loaded (e.g. Lowther Acousta), hybrid ribbon designs (Heil/AMT, Decca, Heybrook Sextets) and latterly Klipsch horns, I decided that the latter held the most potential in terms of bringing performers to life. Reading about bespoke horn projects from the likes of Definitive Audio also reinforced my feeling that horns must represent a sort of ‘ultimate’ reproducer. Given my small room constraints I quickly understood that the key to achieving decent results lay in getting the bass right, and in this respect the little Klipsch Heresy proved a most inspiring starting point. Its sealed enclosure produced tight bass and worked well against the rear wall, so from there it was a case of experimenting... 2 ways, 3 ways, different types of horns (constant directivity, Le Cleach’ ...) made out of solid wood, plaster, reconstituted stone... the options seem endless and trying the horns and driver combinations has been (and continues to be) a lot of fun. Best of all perfectly decent component parts can be had for reasonable money, especially in view of the scary prices which seem to have become the norm, and not just in ‘hi-end’ audio. Onto crossovers. Of course, lots of tools are now available online to help one work out the correct values, but if, like me, you are not particularly technically minded, the whole thing can be quite daunting. Nevertheless there is a solution, and with it another major breakthrough as far as I am concerned: go active! Now, why more isn’t written about active crossovers in hi-fi magazines is a little perplexing. Your good selves once published a rave review of the BSS FDS-388, a landmark digital product in its day but not cheap and a little complex to the non-technically minded, but if I am not mistaken I believe that was the only time. There are, of course, myriad designs available from the golden age of analogue, products from the likes of Pioneer, Sony, Accuphase, Sansui, Audio Research, and even Kondo and the more exotic artisans from Japan. It seems to me that for the best part of 30 years, active crossovers were at the heart of state-of-the-art systems, so it seems a bit of a mystery as to why they seem to have disappeared off the map. Surely it can’t be just the cost of additional amps when some cable manufacturers have the cheek to ask five figure sums for single runs of their top loudspeaker cables? From experience going active renders such tweaking less critical, and that route offers a number of other ways to adjust a system’s sound to one’s personal taste. And that’s without talking about the ‘life-size’ imaging, effortless dynamics, detail... I could go on. Of course there are some downsides. Aside from the aforementioned complexity (more amps required, cables, etc) – imaging is tricky to optimize, phasing issues might trigger bouts of paranoia, but at the end of the day it’s a case of trusting your ears and good old ‘trial and error’. A little bit of patience is all that’s needed really. Anyway the whole ‘going active’ experience has really re-kindled my enthusiasm for audio, and I can’t recommend it too highly. I would be interested in hearing your thoughts on the subject, and perhaps suggest that it could form the subject of an interesting series of DIY articles? Keep up the good work, Gabriel Topalian
A Rane active crossover: plenty of controls for altering crossover frequencies, rate and gain. This is a great way to tailor your own loudspeaker says Gabriel Topalian.
Hi Gabriel - and thanks for your views on the now-rare subject of active crossovers It’s great that you are experimenting and getting good results, with the sense of satisfaction that brings. An active crossover is for the experimenter though and they are, it seems, a dying breed. Also, the topology of an active loudspeaker fed by an active crossover, rather than a passive crossover, is a little daunting. And the bass unit needs to be tailored to the cabinet too, since active crossover cannot compensate for gross mismatches and the time domain problems mismatching may bring (overhang). So although active crossovers are nice to play with, they cannot cope with all issues. However, if you choose high quality drive units and follow their manufacturers recommendations about cabinet size etc then this is a great way to build a loudspeaker. Unfortunately, so few people nowadays would go down this path that the market for active crossovers will be miniscule. And this is why no one bothers to build or sell them any more I suspect. NK PORT DAMPING Having been a regular reader of your magazine for more years than I care to admit, I hope you won't mind me writing with one small query? In your November 2012 review of the Usher Dancer Mini-Two speakers you mentioned the use of acoustic foam to damp down port output and went on to say that a 50% fill of foam made a useful improvement in your test room. I'm interested in understanding a little more about what you did here. I very much enjoy my Dancer Mini-Twos, particularly the full-scale reproduction that they afford, but there are times when, in my 5m x 5m room, a little less would be a bit more! Could you spare a moment to explain what is meant by the term acoustic foam and, also, what the 50% fill means in practice: does this relate to the area of port that is filled (or, conversely, left open) by the foam, or the depth of foam that is inserted into the port? Looking forward to your reply. Kind regards James Batchelor
Loudspeaker foam port bungs. At top is a one piece bung with a flat that allows some air flow. Below is a roll of foam that allows air flow through the centre and wlil fit a slot port. These bungs damp down heavy bass, and tighten it up.
Hi James. Yes, you have a problem there. A 5m (15ft) square room has a big resonant mode at 36Hz and the Mini-Two will excite this strongly because it delivers enormous LF energy. We half filled the port with acoustic foam. It was a 3cm thick slab of foam about 10in long, rolled up into a tube and put into the port. This narrows the port and provides some acoustic resistance. If that is insufficient then the port can be filled completely. You will hear the difference. You can get acoustic foam from Studio Spares (Google it, they are in North London). Your room will boom because it is square. Try and put in the largest volume of acoustic foam possible.Studio Spares sell foam bass traps but you need a lot of them in big volume to absorb bass energy. I hope this helps. NK
MINI TWO TOO I am a USA owner of the Usher Mini-Two loudspeakers, and note that the December issue of The Absolute Sound gives a similarly rave review...and also suggests the need to tighten the low bass. Query, then: exactly what did you do to plug the ports: material, dimensions, etc? M B Rosenberg
We half filled the port with acoustic foam. It was a 3cm slab of foam rolled up into a tube and put into the port. This narrows the port and provides some acoustic resistance. NK
As you suggested, I half filled the ports with rolled up acoustic foam and immediately heard the difference: tighter bass with no noticeable loss of low end response in my 24ft square listening room. Sure did help; thanks from across the pond! M B Rosenberg
Usher Dancer Mini Two produces strong bass and "a little less would be a bit more!" says James Batchelor.
You’re more than welcome. It’s a gloriously simple way to fine tune any reflex loudspeaker. The only other (more expensive) trick is to fill the room with big, deep settees. Most cushions are foam filled and absorb bass energy, damping down room boom.You get a lovely comfortable lounge that sounds great too! And likely a happy wife. NK
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