Totally confused now

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manicm

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Grimaldi:manicm:

Well fine, but if everyone is so sure about lossless formats why do Wadia, in their manual, prefer one to rip music in WAV instead of Apple Lossless format for their 170i Transport? Their reasons are purely for audio quality.

Unless ALAC is an inferior compression technology to FLAC?? In which case a lot theories will need revisiting. I'm still not totall convinced.

The only reason I can think of is that the Wadia dock has to get access to the iPod digital data stream and that this stream has to be converted from ALAC to PCM in the iPod and this somehow overloads the iPod. True the iPod can play ALAC lossless files but would normally output the analogue audio only ... perhaps outputting a digital signal is a bit too much for it.

You are wrong here - the Wadia 170i extracts the pure digital stream from the iPod, bypassing its internal DAC completely if one uses the default digital output. So there is NO conversion happening. Go to Wadia's website to confirm this.
 
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Anonymous

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ianandyr:
gregory:I always thought it was, the quick brown fox jump's over the lazy dog.

ROFL

LMAO!
 
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Anonymous

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gregory:I always thought it was, the quick brown fox jump's over the lazy dog.

Well that seemed to kill off a very enjoyable topic!

Going back to Mike's original question and for anyone else who has yet to rip their CD's and fully embrace this new age, could I possibly ask a couple of probably rather stupid questions?

1. If the sound from media streamers is so affected by the quality of the DAC

a) why do the streamer manufacturers not put better DAC's in them or are there any that do? It seems everyone says the Sonos is one of the best but you need to combine it with a good DAC?
b) might one just as well buy the cheapest streamer available with a descent interface?
c) depending on the answer to b) would it not be better to buy something like a Netgear EVA8000 which is usually cheaper than a Squeezebox and does video (+FLAC) too?
d) Russ Andrews and a number of people on the Naim forum claim that changing the power supply on a streamer (actually the Squeezebox) improves the sound. If the streamers job is just to output 0's and 1's how can this be? What am I missing here?
e) If the Naim HDX (or whatever it's called) is a mini-ITX PC then why has no one else just done this? This post refers to computeraudofile.com that that says the best media server is a Dell PC running XP.

2. How can one judge the quality of a DAC? Is there a particular chipset that one should be looking for? What are the criteria to judge them by?

3. Ashley, you said in one of your postings that FLAC has disadvantages. I understand all the arguments about compression, and they do seem persuasive, but as you have so much experience I would much appreciate your giving your reasons. I would so hate to rip all of my CD's only to find that I had chosen the wrong format.

I have read a number of postings on these forums but I would appreciate any other advice that I might have missed. For example, most people say to use EAC for ripping but I have not seen any recommendations on updating/managing TAG's. If I've understood it correctly, EAC doesn't put any TAG info in FLAC files but they are capable of storing it. Is this correct? Can anyone recommend a good program for managing the TAG info. I see that Linn recommends Ripfactory rather than EAC for this exact reason. Anyone had any experience with this?

Also I've seen various things about the difference between USB and digital outputs and lots of articules on "High Definition" downloads. All these articules seem to always feature the numbers 24/44/192 mixed in with long words, none of which made any sense to me at all. Can anyone explain such things in VERY SIMPLE terms or refer me to some other simple postings? Or at the very least tell me if such things are of any importance!!!!

I do hope my re-opening this topic hasn't offended (or bored!) anyone. But I always thought that the iPod age was merely for the younger generation until I discovered that I could actually download Radio 4 podcasts and listen to them when I want, rather than switching on just as they end. And the sound quality is also so much better than my rubbish DAB signal. Now digitising my CD's doesn't seem such a strange thing to do after all. Maybe one day I might even buy downloadable music... although that would be very strange... and probably not a good idea given how bad I am at doing computer backups!!!!!!!!

Thank you for your patience in reading this and if anyone feels like responding you'd make a very confused old man very happy!
 

mikeinbrum

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I've been doing some head scratching over the last week or so and following the forum topics with interest. I've seen some discussion on the Musical Fidelity A1 which apparently is an integrated amplifier with an onboard DAC and digital input... I'm planning on trying this out with my NAS / SONOS setup to see how it compares with my ARCAM system.

Alternatively I will invest in a seperate DAC. I'm a bit nervous about this as I haven't found anywhere within easy reach where I can try out the difference a DAC will make so I may have to order one over the internet and keep my fingers crossed.... a course of action I'm not too keen on.

If it compares favourably then I'm considering trading the FMJ cdp / amp for this single box. I was considering the AVI ADM9.1 but I have to say (for reasons that are probably totally irrational) I have been put off somewhat by some of the posting from AVI themselves on this topic. For a company that does not have good levels of saturation in the dealer networks, to not submit your products for review to one of the largest circulation hifi magazines seems odd.
 
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Anonymous

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I must say that I'm surprised at the anti Apple stuff that appears on some of the UK Forums, their success alone should be enough to persuade people that most love it because it works beautifully. If you don't like it, it could be you.

EDITED BY MODS - House rules violation

Microsoft dominates the Market, even though Apple will probably surpass their turnover within a year or two because they sell the hardware as well. We designed the original ADM9s with a USB connection so that they'd work with Windows, but it was clear even before we were shipping that this was a mistake. Nearly all the people who contacted us wanting to buy them had recently switched to Apple or were using Sonos etc. Therefore we quickly switched to Optical digital.

People love Apple because it's good looking in a home and the quality is superb both inside and out. It is better designed and built than some high end hi fi too, and that is not just our opinion as a manufacturer with an ex military avionics designer at its head, but also of most who've ever had cause to work on them.

If you have a Desktop or Tower PC, I recommend that you try an M-Audio 24/96 and don't judge it by it's price, because as I've previously explained the cost of the bits to make them is tiny, especially to a massive concern and Market leader like this company. If you have a Laptop, try an M-Audio Transit or, if you want real hi end, an Edirol UA25, which is astonishingly good. For a streaming device, why not buy a Beresford and try that, most people love it and it's a good price because it is sold direct and avoids dealer margins.

Claire

I'd love to see a review in WHF that compares the relative merits of PS3s, Apple's streaming products, particularly the ATV and Sonos etc with the expensive Hi End Servers, so that everyone can understand exactly how they benefit from each choice. Where I think the assessment of all this gear fails so badly is splitting things up into price categories, when companies like Apple will have massive advantages in purchasing power and manufacturing cost savings over a company located in the UK, using old fashioned hand assembly techniques, old fashioned through hole components and buying in hundreds or less rather than millions.

MikeinBrum

I'm sorry that you have ruled us out, I think you'd have been very surprised if you'd heard ADM9.1s. I'm certain that they are far better than you expect and I believe this is because the magazines that you are so keen to have review them, don't have sufficient understanding to realise the enormous benefits to performance the technology we've used can provide. There is a big difference in sound, so they are more likely to think it is us that is wrong than what they are used to. Likewise with dealers, as I've already explained, they don't want more for less, they'd prefer to sell higher margin products that are upgradeable and keep computers out altogether IMO.

AVI got a series of rave reviews back in the nineties and demand rocketed. It caused us massive production headaches and even bigger financial ones. This time we've teamed up with www.ls-design.co.uk so that we can use components that they already buy and so that we have access to modern Robot building techniques that give greater reliability and save a considerable amount on building costs. LS also have a massive productive capability. Our biggest problem is drive unit and piano black and white cabinet supply that comes a long way by boat. We've run out of both and won't have more white till March.

What all this means is we can sell more than enough direct and through our few loyal dealers and agents and that we don't need to approach dealers to help us yet. I don't think they'd support us anyway because we've had literally hundreds of complaints from people who do understand what we're selling and have been infuriated by misinformation, dismissal and prejudice shown by shops ignorant of the fact that most of the music we've all been buying for the last twenty years or more, has probably been made on a Computer. Mostly likely an apple Computer that Audiophiles so love to hate. Have a look at Logic Studio 8, which is regarded by Sound On Sound (probably the world's most influential Pro Audio Mag) as the best.

EDITED BY MODS - HOUSE RULE VIOLATION. PLEASE DON'T PUSH IT, ASHLEY!
 
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Anonymous

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Mike, good luck with the A1, I hope it goes well. I'm afraid I can't offer much advice but I did audition the original A1 and it had a lovely sound. However it ran extremely hot. Hence the strange shape as it needs to loose it's heat through the top. If the current model is the same design you wouldn't want to put anything near it and you certainly wouldn't want to touch it. It also doesn't have much power so you need to check whether it can drive your speakers.

If anyone responds to my questions it may take some of mystery out of buying a DAC. I purchased a Fubar III DAC/headphone amp direct from Canada (when the pound wasn't so low!) and I like the sound. But I only use it with my computer to listen to Internet radio. It certainly was a big improvement over my Creative Labs soundcard and with a USB port it was very easy to get working, with no need for drivers etc. I've never tried it with my main stereo though and I've no idea how it compares with other DAC's.

You could always buy something like the Cambridge DACmagic and if you don't find it gives the improvement you want with the Sonos all is not lost. You can always use it to connect a computer to a stereo and at £199 it is not such a risk as changing your amp. I also suspect that you could easily sell it if you decided it was not for you. Maybe Richer Sounds would even let you try it at home?
 

Clare Newsome

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Ashley James:I think you'd have been very surprised if you'd heard ADM9.1s. I'm certain that they are far better than you expect and I believe this is because the magazines that you are so keen to have review them, don't have sufficient understanding to realise the enormous benefits to performance the technology we've used can provide.

Yet again, baseless insults, Ashley. You don't know our test team, so please don't insult them.

And as to your point about us reviewing things by price....I'm not going to apologise for that. We review on true value - performance per pound - as (especially at the moment) readers deserve to find the best for their budget - as well as knowing the increase in performance they could buy by jumping to the next-level up of class leaders.
 

Alec

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mikeinbrum:I've been wanting to try out a pair of ADM9.1s but living where I do in Northampton

There is a list of stockists on teh AVI site and one is indeed right in the centre of Northampton (or at least this was true when last i checcked a couple weeks ago). EDIT - go to the home page and click "contact and online store" down the left hand side).

Mr AVI may have been too concerned with arguing the toss and speaking down to people to let you know that. Quite a sales technique. I want to audition them too, gawd luvus!

Cant reply at length now but i have some more thoughts for later if the thread isnt locked by then.
 
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Anonymous

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Ashley,

Your extreme arrogance is unlikely to win many converts. So you like Apple and others don't. Why do you make such an issue of it? Do you actually believe that everyone must be wrong if they don't agree with you? Just because they choose not to use Apple!!! I had an open mind on your comments and asked you for a simple clarification. Instead you choose to rant! If you are doing so well why do you feel the need to act like this?

I repeat my question in the hope that you can bring some level of understanding to people like me who are trying very patiently to understand whether or not you have valid points to make.

"3. Ashley, you said in one of your postings that FLAC has disadvantages. I understand all the arguments about compression, and they do seem persuasive, but as you have so much experience I would much appreciate your giving your reasons. I would so hate to rip all of my CD's only to find that I had chosen the wrong format."
 

chebby

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I do hope that the thread is not locked due to AVI blitzing it with insults and bludgeoning, sub-'Amway' style sales pitches.

I realise the hifi industry is always going to have different approaches to new trends in media (entrench, embrace, experiment, evangelise, reject, compromise etc etc.) and this reflects the attitudes of different company's customer bases to some extent.

I cannot accept that AVI are ever going to sweep the world clean of the 'evil' traditionalists nor will they convert all the misguided souls who use PCs! (I use both PCs & iMac and iTunes so I suppose I am only half misguided.)

I find the alternate tub-thumping/evangelising/bullying and the.. "you cannot possibly know anything you ignorant saps" approach to potential customers & past reviewers (highly positive past reviewers at that) somewhat perplexing. Do AVI want to attract people to their product or not?
 

Alec

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chebby:Do AVI want to attract people to their product or not?

Aparently not. The attitude seems to be 'we're doing ok without them'.

But then we get the big pitch...Curious...
 

mikeinbrum

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al7478:mikeinbrum:I've been wanting to try out a pair of ADM9.1s but living where I do in Northampton

There is a list of stockists on teh AVI site and one is indeed right in the centre of Northampton (or at least this was true when last i checcked a couple weeks ago). EDIT - go to the home page and click "contact and online store" down the left hand side).

Mr AVI may have been too concerned with arguing the toss and speaking down to people to let you know that. Quite a sales technique. I want to audition them too, gawd luvus!

Cant reply at length now but i have some more thoughts for later if the thread isnt locked by then.

I think i checked this out a few weeks ago too. Gave the number a call and got through to some old dear who got quite cross when i asked her if she was the owner of a hi-fi shop! Must be an out of date listing sadly.
 

Alec

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mikeinbrum:
al7478:mikeinbrum:I've been wanting to try out a pair of ADM9.1s but living where I do in Northampton

There is a list of stockists on teh AVI site and one is indeed right in the centre of Northampton (or at least this was true when last i checcked a couple weeks ago). EDIT - go to the home page and click "contact and online store" down the left hand side).

Mr AVI may have been too concerned with arguing the toss and speaking down to people to let you know that. Quite a sales technique. I want to audition them too, gawd luvus!

Cant reply at length now but i have some more thoughts for later if the thread isnt locked by then.

I think i checked this out a few weeks ago too. Gave the number a call and got through to some old dear who got quite cross when i asked her if she was the owner of a hi-fi shop! Must be an out of date listing sadly.

Sorry about that. I was surprised there was one there as i went to uni in northampton a few years ago, and there was a favourite pub of mine a few doors away.

Spose i might owe you a wee apology too Ashley. Just a very wee one tho.
 

Tony_R

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DLD:<snip>....d) Russ Andrews and a number of people on the Naim forum claim that changing the power supply on a streamer (actually the Squeezebox) improves the sound. If the streamers job is just to output 0's and 1's how can this be? What am I missing here?....<snip>

DLD, the reason for changing (upgrading) the power supply is because the more stable and noise free the power supply is, the better the quality of the resulting signal from the device it is supplying power to.

It is well known that power supply noise and bad regulation in a CD player (or any digital device / DAC) can result in inferior sound quality.

This is due to inaccuracies introduced in the digital to analogue conversion process, introduced by power supply noise.

Regulation = the ability of the power supply to maintain a constant steady output under all load conditions.

Noise = any noise superimposed on the DC voltage from the power supply - this could be noise from the power supply itself - and more commonly noise from the oscillator(s) within the DAC getting back into the power supply.

Oscillator = a device that provides a constant rythmic pulse or series of pulses for the various (digital) circuits within a CD player.

Pardon me if I have oversimplified this for you -

Tony.
 
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Anonymous

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Tony_R:
DLD:<snip>....d) Russ Andrews and a number of people on the Naim forum claim that changing the power supply on a streamer (actually the Squeezebox) improves the sound. If the streamers job is just to output 0's and 1's how can this be? What am I missing here?....<snip>

DLD, the reason for changing (upgrading) the power supply is because the more stable and noise free the power supply is, the better the quality of the resulting signal from the device it is supplying power to.

It is well known that power supply noise and bad regulation in a CD player (or any digital device / DAC) can result in inferior sound quality.

This is due to inaccuracies introduced in the digital to analogue conversion process, introduced by power supply noise.

Regulation = the ability of the power supply to maintain a constant steady output under all load conditions.

Noise = any noise superimposed on the DC voltage from the power supply - this could be noise from the power supply itself - and more commonly noise from the oscillator(s) within the DAC getting back into the power supply.

Oscillator = a device that provides a constant rythmic pulse or series of pulses for the various (digital) circuits within a CD player.

Pardon me if I have oversimplified this for you -

Tony.

Tony,

Thank you for your reply. I can see from your explanation how noise can affect the digital to analogue conversion. But if that conversion is happening as in the examples I have read about in the amp i.e. the Supernait, what I don't understand is how changing the power supply for the streamer affects the sound. Surely, if the streamer is outputing a digital signal the Supernait is either getting it or it isn't. I can see that changing the power supply on the Supernait can affect the the quality of the sound but I don't get how changing the power supply on the streamer affects it?

Are you saying that in fact the noise from the power supply on the streamer is forwarded to the Supernait as part of the signal? I'm afraid I don't understand how these things work so I assumed that it was like the signal I get to my SKY box and DAB. When it looses the signal I get complete rubbish (and often a terrible noise!), whereas with my FM signal I get noise added to the sound. Is that an applicable analogy or is it completely erroneous?

And please don't apologise... simplified is good!!!!!
 

Tony_R

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DLD:Tony_R:
DLD:<snip>....d) Russ Andrews and a number of people on the Naim forum claim that changing the power supply on a streamer (actually the Squeezebox) improves the sound. If the streamers job is just to output 0's and 1's how can this be? What am I missing here?....<snip>

DLD, the reason for changing (upgrading) the power supply is because the more stable and noise free the power supply is, the better the quality of the resulting signal from the device it is supplying power to.

It is well known that power supply noise and bad regulation in a CD player (or any digital device / DAC) can result in inferior sound quality.

This is due to inaccuracies introduced in the digital to analogue conversion process, introduced by power supply noise.

Regulation = the ability of the power supply to maintain a constant steady output under all load conditions.

Noise = any noise superimposed on the DC voltage from the power supply - this could be noise from the power supply itself - and more commonly noise from the oscillator(s) within the DAC getting back into the power supply.

Oscillator = a device that provides a constant rythmic pulse or series of pulses for the various (digital) circuits within a CD player.

Pardon me if I have oversimplified this for you -

Tony.

Tony,

Thank you for your reply. I can see from your explanation how noise can affect the digital to analogue conversion. But if that conversion is happening as in the examples I have read about in the amp i.e. the Supernait, what I don't understand is how changing the power supply for the streamer affects the sound. Surely, if the streamer is outputing a digital signal the Supernait is either getting it or it isn't. I can see that changing the power supply on the Supernait can affect the the quality of the sound but I don't get how changing the power supply on the streamer affects it?

Are you saying that in fact the noise from the power supply on the streamer is forwarded to the Supernait as part of the signal? I'm afraid I don't understand how these things work so I assumed that it was like the signal I get to my SKY box and DAB. When it looses the signal I get complete rubbish (and often a terrible noise!), whereas with my FM signal I get noise added to the sound. Is that an applicable analogy or is it completely erroneous?

And please don't apologise... simplified is good!!!!!

DLD, I'm not familiar with the workings of the Supernait device, but I suspect the streamer you refer to is also a digital device parsing some kind of digital signal from the Supernait. This digital signal needs to be jitter free. Jitter is analogous to wow and flutter on turntables / tape decks, but in the digital domain. A digital signal is a square wave having a regular pulse (here's the oscillator again) - and any variation in this square is referred to as jitter - resulting in errors in the digital signal. That's probably a drastic oversimplification but I hope you get the point!

In essence your analogy of your Sky box / DAB vs FM is correct. Sky and DAB are both digital signals, dependant on regular clock (oscillator again!) pulses, to keep the signal locked. Any (drastic) variation or loss of that signal results in all manner of odd noises as you have experienced. However, FM is pure analogue, so a weak signal results in a gradual fading (and noise being added to the sound as you say) and eventually loss of audio, resulting either in hiss or (if you have muting switched on) no sound at all.

Tony.
 
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Anonymous

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ifitsoundsgoodlistentoit:Ashley James:ifitsoundsgoodlistentoit:Ashley James:The point is that all digital sources are the same, so a CD will sound the same from any Computer as it does from a CD player provided the DACs used are of the same quality.

Ash

im sorry but that is just wrong. digital sources are not the same. they are the sum of the parts used to build them! a £10 CD/DVD drive in my PC isnt going to read a cd the same way a £2000 dedicated CDP will. my £1000 DV135 will also read/extract data differently. do some back to back tests listening to files ripped losslessly via various cd/dvd drives onto the same PC and you will hear the difference

No I'm sorry but you're wrong. For a start you can buy a better CD/DVD Rom for your computer and if you use error correction there will be no difference.

The thing you must remember is that it's likely that all the music you buy will have at least in part, been made on a computer.

You also need to be aware of the fact that for the last 10 years CD mechs have been dropping in price and quality to meet market requirements. They don't last long and they are much more troublesome than HDs are now. I'm a manufacturer who decided not to make any more and this is one of the reasons. The other was a fall in demand.

Please understand that I'm simply explaining what is happening and why I think it's happening. Don't attack the messenger, just read the message and think about it.

All digital sources are the same and if you did properly conducted tests with all the levels properly matched and invisible switching you'd find you were wrong and that you couldn't hear the differences you believe you can. I'm sorry to be so blunt, but you're just one of a tiny minority out on a limb. The world is switching to Media Computer type devices and hi fi is a casualty at the moment.

Ash

but ashley why would i need to buy a better drive if they are all the same?

error correction? where do the errors come from? surely not from the digital device reading the digital media?

yes some of the music i own has been produced partially on a computer - what was your point?

not all cd mechs have dropped in price and quality - some manufacturers are still trying to perfect them - to reflect the demand in the market

dont know anyone who has had a mech fail on them btw

you dont know me so please dont tell me i am part of a minority

if hi-fi is a casualty the sales figures arent reflecting it. the only hi-fi casualty i can think of is Naims HDX (in terms of sales figures)which incidentaly is a Media Computer type device - go figure?

im not sure why i thought Ashley would have the decency to respond to my perfectly reasonable questions... seems rational debate is not something he cares to deal in
 

Alec

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ifitsoundsgoodlistentoit:ifitsoundsgoodlistentoit:Ashley James:ifitsoundsgoodlistentoit:Ashley James:The point is that all digital sources are the same, so a CD will sound the same from any Computer as it does from a CD player provided the DACs used are of the same quality.

Ash

im sorry but that is just wrong. digital sources are not the same. they are the sum of the parts used to build them! a £10 CD/DVD drive in my PC isnt going to read a cd the same way a £2000 dedicated CDP will. my £1000 DV135 will also read/extract data differently. do some back to back tests listening to files ripped losslessly via various cd/dvd drives onto the same PC and you will hear the difference

No I'm sorry but you're wrong. For a start you can buy a better CD/DVD Rom for your computer and if you use error correction there will be no difference.

The thing you must remember is that it's likely that all the music you buy will have at least in part, been made on a computer.

You also need to be aware of the fact that for the last 10 years CD mechs have been dropping in price and quality to meet market requirements. They don't last long and they are much more troublesome than HDs are now. I'm a manufacturer who decided not to make any more and this is one of the reasons. The other was a fall in demand.

Please understand that I'm simply explaining what is happening and why I think it's happening. Don't attack the messenger, just read the message and think about it.

All digital sources are the same and if you did properly conducted tests with all the levels properly matched and invisible switching you'd find you were wrong and that you couldn't hear the differences you believe you can. I'm sorry to be so blunt, but you're just one of a tiny minority out on a limb. The world is switching to Media Computer type devices and hi fi is a casualty at the moment.

Ash

but ashley why would i need to buy a better drive if they are all the same?

error correction? where do the errors come from? surely not from the digital device reading the digital media?

yes some of the music i own has been produced partially on a computer - what was your point?

not all cd mechs have dropped in price and quality - some manufacturers are still trying to perfect them - to reflect the demand in the market

dont know anyone who has had a mech fail on them btw

you dont know me so please dont tell me i am part of a minority

if hi-fi is a casualty the sales figures arent reflecting it. the only hi-fi casualty i can think of is Naims HDX (in terms of sales figures)which incidentaly is a Media Computer type device - go figure?

im not sure why i thought Ashley would have the decency to respond to my perfectly reasonable questions... seems rational debate is not something he cares to deal in

Doesnt ashley also say that the only thing taht makes a difference is the DAC? in that case, are there dacs in CD drives? I donty think there are (i could be very wrong), so it would make no difference if you got a better drive.

There seems to be some confusion tho as to when people are talking about playing CDs from a PC and when theyre tallking about files derived from those CDs. CDs on my PC do indeed sound obvious;y inferior to files ripped from them. I must mention that in "that other thread" where it is perhaps more relevant.
 
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Anonymous

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Tony_R:
DLD, I'm not familiar with the workings of the Supernait device, but I suspect the streamer you refer to is also a digital device parsing some kind of digital signal from the Supernait. This digital signal needs to be jitter free. Jitter is analogous to wow and flutter on turntables / tape decks, but in the digital domain. A digital signal is a square wave having a regular pulse (here's the oscillator again) - and any variation in this square is referred to as jitter - resulting in errors in the digital signal. That's probably a drastic oversimplification but I hope you get the point!

In essence your analogy of your Sky box / DAB vs FM is correct. Sky and DAB are both digital signals, dependant on regular clock (oscillator again!) pulses, to keep the signal locked. Any (drastic) variation or loss of that signal results in all manner of odd noises as you have experienced. However, FM is pure analogue, so a weak signal results in a gradual fading (and noise being added to the sound as you say) and eventually loss of audio, resulting either in hiss or (if you have muting switched on) no sound at all.

Tony.

Tony,

Thank you for the explanation. I think I understand it but I never did pay attention in physics!

What I'm still not understanding is how it relates to the binary data that is being transferred. I look at these things from a computer perspective and I assume that all the data stored on a CD is just binary data. And I assume that a ripped CD is just binary data with a level of compression. I see that the job of the DAC is to turn this data into an analogue signal and that this process can happen in the streaming device, a CD player, a separate DAC, or an amp. From your explanation of jitter I can see that at any point the signal can become distorted. But what does this mean in terms of the binary data? Does it mean that the data being received is incorrect, is there more information being transferred, or am I just being way too simplistic? When the data from SKY or DAB is broadcast does the receiver know if it's missing any data (is there some sort of checksum?) or do the weird noises mean it thinks that it's real data?

BTW, the streaming device I'm referring to is a Squeezebox 3 so essentially the same as your Roku.

On a related topic to this, I've never understood what people mean when they talk about digital amplifiers. Isn't the job of an amplifier to take an analogue signal and amplify it? How can an amplifier be digital? Sorry if this question is rather basic but I really don't mind looking stupid!

Ashley,

If you are still reading this I would just like to point out that the wonderful thing about the forums is when people like Tony explain things in simple terms to people like me who should have paid attention in physics classes but never thought anything they were being taught would ever be of any use. If you could follow Tony's example and educate us with a level humility then everyone would gain. You would gain much more respect than you are currently getting too!!!!!!!!!!!

To everyone else I do apologize if this is way too basic!
 
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Anonymous

Guest
I've just seen you comments so will add that jitter is only an issue when you either A to D or D to A and that modern DACs are largely immune to it. In addition to this, Manufacturers Application notes explain various ways of reducing it or removing it. Because ADM9.1s are used in Studios we use a sample rate convertor like Benchmark do to remove it altogether.

Devices like Airport Express, Roku, SB, ATV, PS3 or whatever all receive bit perfect information in the same way and will either work or not. They cannot function less well because the cable isn't right. All you'd get is drop outs or no sound.

CD's are stored differently on a computer to a CD player. A CD player has redundant data, it makes one pass, does the maths and if it doesn't get enough data, it first guesses and if that doesn't work, it mutes until it's collected its thought. It does this quickly so you don't notice.

A computer is different, HDs keep reading until they have all the Data. They load information onto the ram and do a checksum. Once they have all the noughts and ones in the program, they play it perfectly every time. They read CDs as CD players do, but once they have a read, it never alters any more than any other of the many programs you run.

Class D Amps are digital because they switch on and off thousands of times a second to produce the music. They are more efficient but have more distortion and a higher output impedance than Analogue Amplifiers. They are what you find in Telephones, PMPs and car audio where current consumption is an issue. There are some for hi fi and they are better than some analogue amplifiers, but not as good as the best.

I hope this helps and I'm forgiven.

Ash
 
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Anonymous

Guest
Ash,

You are forgiven. Concise, informative and very well written. What more could I ask for?

Now I have a suggestion for you. Why don't you hold an open day and invite members of the forum to attend a blind test of your equipment versus other equipment, of which you approve, brought along by a member of the forum or WHF? Someone on the forum could then write up an agreed summary for those unable to attend and WHF could publish it. You get fair hearing, the forum members gain greatly and WHF gets an interesting piece to publish! What do you think?

Clare, would it be of interest?

DLD
 
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Anonymous

Guest
I've thought of that and as you know everyone except Drummerman is welcome for a free lunch provided they make sure we're there to see them.

Ash
 

Messiah

Well-known member
Ashley James:I've thought of that and as you know everyone except Drummerman is welcome for a free lunch provided they make sure we're there to see them.

Ash

Seems to good to refuse! Can we get it arranged?? Where are you based??
 

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