Advice sought - a frequency problem

Well, firstly commiserations.  There's nothing worse than a single aspect killing your enjoyment.

I would try moving the S400 a few centimetres away from the wall to see if that makes a difference.  I used to run a pair of S600s and when they were run in they tended to sound at their best 36cm away from the back wall.  I found that the BMR drivers can sound a little hard if they're not operating in free air.

Failing that as you've only had your S400s for a few months I'd pop them back to the dealer for a quick checkup . . .

One question: (ignoring the Xbox) I've assumed this effect occurs on all sources, is that right?

Are you using Ovator-specific speaker pins on your S400's?  This will make a big difference in sound quality.  Also, poor solder joints will also contribute to harness. 

I'd have your dealer order new Ovator speaker pins and have both ends resoldered.  A cheap and easy thing to do. 

Chris, yep, using Ovator pins, freshly soldered a couple of months ago.  Also using standard Naim pins at the 250 end.

Charlie.  Thanks.  Can't really take them back, as they were from a dealer miles and miles away, due to a big discount offered on their last stock.  Not sure how much further out I can bring them in my room, they're already 35.5cm out from the wall at their nearest edges (just a slight toe in).  But I'll try.  The only other source I use is the occasional spin of vinyl, I'll have a go and confirm whether it's present with that too.

The system does have mullet qualities, with the 172 then the 250 and 400s, but others have reported using the 172 to front much bigger systems, albeit temporarily, without problems. I suppose you could try borrowing a 272 and seeing it that fixes it. You don't really want to throw money at the problem, I'm sure, but I'm not sure what else to suggest. You have the right speaker plugs, the speaker position sounds fine. Is the earth switch on the 172 in the right position - I'm not sure which it should be with a turntable attached, but you could try swapping it round. I've not been much help really - sorry. 

Don't use MinimServer, it sounds thin and the trebles are harsh.

That's a very bold statement, and the total opposite to what I found when I used it. 

It's possible the rough adges of the 172 showing through but paying attention to setup canhelp a bit. You may well have all this covered but in case you haven't.

Anything with a switching mode power supply shouldn't be plugged in near the Naim boxes, preferably on a different ring or spur.

make sure no cables are touching the rack or wall and if possible each other, particularly power cables. My system used to make high piano notes ring unpleasently when the CDX2's power cable rested on the rack.

you don't use a steel framed rack by any chance? or have one near the system?

Martin.L posted:

Don't use MinimServer, it sounds thin and the trebles are harsh.

Media servers don't carry any data so how can they affect sound.  They enable the various devices to discover each other & for them to connect & transfer data,  but UPnP/DLNA media servers as such do not carry data - that is carried over the ethernet cables (or wireless)

When MinimServer is running on the NAS, the Ethernet interface is carrying HTTP packets to stream the music. When MinimServer is running on the PC, the Ethernet interface is carrying SMB/CIFS packets to stream the music.

Besides, I can hear the differences between UPnP media servers running on the same hardware.

I'm so happy that naim audio learned to ignore the messages of doom from computing "scientists" and developed their own UPnP media server software
(UnitiServe/UnitiCore/...), which can certainly affect the sound quality.

Dave - can you describe the room, especially the vertical surfaces behind the speakers and your listening position? I don't think it's a source problem or speakers. 

What you've described sounds more like a specific acoustic problem with a room - a certain frequency range is resonating louder than the rest.

Dave***t posted:

The problem is that there's a fatiguing, hard, forced sounding aspect to the upper mids.  It's a bit difficult to describe, but if there's anything like a prolonged flute note or a held high note in a blues guitar solo, I can't wait for it to end.  The issue is with those sorts of frequencies, rather than those styles of music, the examples are just to illustrate.  Some voices hit it too.  Roughly, it's the opposite of what I understand 'relaxed sounding' to mean - stressed sounding?  Worse on some tracks than others, depending presumably on the mastering.  It's not the higher treble

I battled a very similar situation for over a year. Turns out it wasn't my system - it was me. I did all sorts of sorting to my system, tried room treatment, rack treatments, cables, power strip, whatever. Nothing worked. It was tough for me to recognize it was my ear because I have bad seasonal allergies with a lot of head congestion during heavy pollen periods. Finally visited an otologist and determined I had a blocked Eustachian tube and my ear drum wasn't moving properly.

Could be a longshot in your case except that your description of what you are hearing is eerily close to what I heard. 

Load a $5 8GB thumb drive with WAV or AIFF songs and plug it into the front of your 172, for reference.

If it sounds great, you can rule some things out.

Best,

Nick

Martin.L posted:

When MinimServer is running on the NAS, the Ethernet interface is carrying HTTP packets to stream the music. When MinimServer is running on the PC, the Ethernet interface is carrying SMB/CIFS packets to stream the music.

Besides, I can hear the differences between UPnP media servers running on the same hardware. 

Whats that got to do with different UPnP media server software on a NAS;  a NAS is different to a PC as it is different to a US or Core .......... a copypaste maybe

If you just have a believe that it sounds different,  like the last line,  thats OK to say so.       

Martin.L posted:

Don't use MinimServer, it sounds thin and the trebles are harsh.

Hmm, strange comment to make unqualified. UPnP media servers once the media is transferring simply send packets with the payload of the sample data from source  to destination (media server to streamer) . These packets are chopped up into a sequence and are managed by the TCP transport protocol. This transport control has many characteristics but is for the most part controlled and negotiated by the source and destination network stacks.. and these are controlled by the operating system / hardware of the media server machine, Now I have found that different TCP flow characteristics and the inter-frame timing do produce subtly different audio sound on the current Naim streamers.. no doubt for the same reasons why FLAC and WAV can sound subtly different... i.e. side effects of logic/digital electronics noise.

Therefore Minimserver may sound different from other media servers, but it will be largely down to the coupling  of MInimserver (or more accurately Minimstreamer) with the local operating system, and so may sound different on different platforms such as different types of NASs, RPi, PC etc. This goes the same for Asset and others.

Perhaps a clue is in the optical Xbox connection, if this sounds fine with CD playback. This will effectively electrically isolate your 172 from noise and distortion from the source (Xbox). If Xbox sounds fine then it's more than likely noise and distortion getting injected into your 172 from whatever the input source is.

Go back to basics, strip system and try one component at a time, take off all the chokes, stick to stock cables, and make good your cable dressing (no cable should really be touching each other). Process of elimination. If no joy then you may need to check speaker or listening positions, do you get the problem no matter where the speakers or listening position are? The clap test previously suggested was a good idea.

Hope you get it sorted, sounds very frustrating. It could be that you are just not getting on with one of your components such as speakers or 172.

Thanks for all the helpful comments, much appreciated.

I'm off to Norway for the weekend to do a gig, but will investigate all the suggestions when I get back.

What NickSeattle said. That would rule out - or ascertain - that it's networking that's the issue.

the network was an issue for me for many years ...

Martin.L posted:

Don't use MinimServer, it sounds thin and the trebles are harsh.

As I read this comment I happened to be listening to my more modest system playing from my QNAP NAS running MinimServer.  Intrigued, I listened hard for the thinness and harsh treble you encountered.  But it sounded sweet as a nut, so I went back to enjoying the music.  Thinking about it later, though, I suspect your system was not set up optimally.  I would urge you to post your findings on the MinimServer forum.  The community there is very helpful and the developer, Simon Nash, is very responsive and frequently goes well out of his way to sort out the problems that people encounter.  Indeed, I would rate him one of the really good guys of computer audio, so perhaps you owe it to him to take up the issue before posting this unqualified statement.  Apologies if you have already done so.

Roger

Try removing all the ferrite chokes.

A bit of an update.  Thanks again for the suggestions.

I've now tried a number of the free things:

• Removed any toe in of the speakers - now flat 36cm from wall
• Ensured that no wires are touching one another (maybe slightly improved SQ, but not in a way that helped the problem as far as I could tell)
• Tried removing the ferrite chokes (no discernible effect; replaced)
• Tried connecting via wifi rather than ethernet cable (no effect; replaced)
• Played from a USB stick (tricky to tell, no big difference if any)
• Disconnected the DIN cable from the turntable (couldn't tell a difference)
• Room acoustics DIY - found first reflection points for each speaker & placed cushions/curtain in the way

The above has helped.  It's not cured the issue, but it's improved things.  I think the most significant were removing speaker toe in, and the admittedly very amateurish cushions on the wall.  It's now at the point where a cloth eared layman (i.e. anyone normal) probably wouldn't notice it.  But if you're a bit obsessive about sound (i.e. most of us strange people), it's the kind of thing you can't ignore.

I'm left thinking that it's most likely down to room acoustics, as Adam suggested.  The room is quite small, with a largely bare plasterboard wall behind the speakers.

So, some thinking points I'll have to ponder.  

Does acoustic treatment (limited to something along the lines of a Gik ArtPanel or two) behind the speakers make much difference?  Can one try before buying with that sort of thing?  The room's got a well carpeted concrete floor, mostly plasterboard walls, 3.3m wide (speakers along that wall), about 2.3 high (plastered ceiling), and I sit about 3.4m back from the speakers with space behind me, but the space behind is too narrow to move the settee back very far.  There's no real scope for changing the room layout because of where the windows are, stuff needing to fit in it etc.

I'm probably a bit 'over speakered' for the room, but I'm loathe to change the S-400s - I like what they do well, and I won't be in this flat forever; if I can change other things and get along with them here, I want to keep them indefinitely.  They also have personal significance because of where the money to buy them came from.

I'm considering an upgrade in the summer, as it's my 40th this year.  But the 40th part also means I want to be sure, and keep the equipment for  long time.  I was considering a 272 - I've seen them described as slightly warmer than the 172, and I still wonder if I'm hearing the limitations of the digital side of the 172.  But perhaps a more radical change would be better.  That creates a bit of a problem, because I'm in Birmingham and the nearest dealer with e.g. Chord stuff as well as Naim is probably Audio T in Cheltenham - happy to have a bit of a day out to audition, but can't really get them to pop round and advise in case of difficulty.  It also means that trying one bit at a time at home would be laborious if there were several options.  Maybe a 272 would help a bit, and a local dealer would be able to help a bit more.

Any further thoughts welcome.  I'll keep thinking.

Good to hear that things are getting better. I use two Artnovion Douro diffusers on the wall behind my speakers. They are placed between the speakers at ear height. Highs and midrange are less congested and the soundstage is a little deeper as well. The German distributor was kind enough to let me try a single one before purchase.