Well I finally have my DAC in and running thanks to some dodgy TOSLINK cables.

It's amazing the difference back to back (with the simple unplugging of the TL cable) between digital and analog. (i.e Using alpine head unit DAC and external PPI DAC).

The PPI DAC difference is really only on the mid-high to highs. There's a definate +dB in output (but only slightly) but really the difference is in the clarity, and presence of the highs. It just really clears it up.

I went on to demo "My Disc" and the live studio recording of 'Dock of the bay' (instrumental) there is audible talking picked up from what I assume is the mic'd up acoustic guitar or another instrument. Previously (other source units and no DAC etc) most of what was being said is not able to be heard, but now it can be heard clear as day. There is also what sounds like a cable being plugged in (static) from the left channel a couple of seconds in. I played it back and back again to confirm it was in the recording, and then pulled the digital cable so as to use the internal head unit DAC. You then can't hear the alleged cable being plugged in!

So there you have it. I've just done my own little experimenting and proved a couple of things to myself. Not preaching for everyone to go out and buy external DAC's, but hey I've tried it and know that I would now not look back.

I'm actually EXTREMELY happy with the sound and accuracy I have now, with no equalisation at all. I will be adding "some" eq later... but I'm quite happy for now.

Do a level check with a CRO. Then do a back to back blind test.

Often a 2-3dB level increase gives a false sense of "SQ"

Phil

Yeah, you've gotta love the sensitivity of those horns too, they really reveal details like this that you may not hear through 'normal' speakers.

I don't think its that much of an increase in output actually. There is a marginal difference (not sure why really) between dB output of digital vs analog.

I know what you mean however with an increase.

But detail is detail, its still there if I turn it right down when running digital.

I'm probably making the horns do what they are capable of now... as Damon mentioned. Very Happy

good to hear you sorted it out! :thumb:

i look forward to an audition.

Hanging for a meet now

Use co-axial digital rather than optical if you can (for obvious reasons).

Phil

Only pure 75ohm coaxial cable and interconnect. The magic is in there.

Explain "pure".

Do you mean RB59BU at $1 a meter or $1000 per metre cables that are stamped with a direction indicator??

Cables designed to carry an AC electrical voltage, labelled with a direction, can you beleive it?

Yet I'll bet, every schmuck who spends $1000+ on an RCA cable will argue till he's blue in the face that it sounds better.

OF COURSE, if you can convince yourself to spend a $1000+ on a cable it will sound better to you, you've already convinced yourself before even listening.

Bring on the double-blind test.

Phil

/ B O R I N G

umm, sorry, but i'm not even aware of any 'obvious' reason. :?

over 3~5m, i don't think even you would hear the difference between fibre optic and electrical digital cables. unless you're referring to the $1000 directional ones.

anyway, i'm curious as to what the 'obvious' reasons are. [maybe you were being sarcastic :| ]

I am not talking about how much dollars a cable must be use, I am refering only the digital transfer stage using a pure 75ohm plug and cable. It can cost as little a $150 a meter with plug. Is that cheap enough for you, or is it still to expensive MR DD PHIL???

I will take you on Mr DD Phil, I really want to see how much you know in Audio. Double blind test anytime, most welcome.

Anyway my car is ever ready for this test. Stop talking! Listen!!!

Do you know how many ohm is there in a conventional RCA plug?
Do you understand the different of how a digital transfer between coaxial and toslink?
What kind of bandwith went transfering digital signal in coaxial?

Will see how good your car can sound. Or home too? Will like to meet you face to face in QLD auto saloon CAASQ comp or any other QLD comp if you can come up with one.
Really excited with your DD: the most successful woofers. EVER . Possible?



Have you hear one, if not keep quite. Until you hear one, then comment.



Never have I agree that a cable will make it sound better!!!

Well you asked for it.

1. If you want to send data over 1000km, optical is the way to go. No arguement. Telecommunications, data ,all with check digits etc.

2. RCA cables with direction indicators are stupid because an audio signal is AC not DC. Think about it.

3. Over short cable runs, co-axial is superior to optical because there is less processing and down-conversion.

A data stream from a CD/DVD in the digital domain is electrical. To go optical (ie Toslink) requires a conversion to a light pulse. This in turn requires down-conversion at the other end back to electrical signals.

More processing = more noise / distortion

Phil



I always try to avoid to getting personal but since you started it:

1. I studied Micro Electronic Engineering, and Industrial Design for 5 years.

2. I owned a high end (one of the most successful ever) audio shops for 12 years.

3. When IASCA SQ was set up in Australia I TRAINED the judges.

I'm sorry, but from a scientific point of view, someone selling you a $150/m cable is ripping you off.

I welcome any double blind cable test in a moving vehicle.

Phil

Oh well its sure personal from your post. We will me in QLD comp.

It'll never work Phil. I've tried it. You can have them sitting there dumfounded wondering why all of a sudden that incredible difference their ridculously expensive cables supposedly cause, is gone, but theres ALWAYS an excuse, which is ALWAYS irrational, and they always go back to thinking what they want to think even when they've been shown its wrong, because thats what they WANT to think...

Audio is like religion to some people : You beleive what you want that makes you feel how you want to feel, and damn the facts.

R you guys kiding ? Get your sound stage right first then worry about the cable !

Agree - coax should be measureably (accoustically I dunno) better than optical due to jitter induced by A-D->light->light->D->A vs A->D->D->A

The spdif standards dictate that the output is 1vp-p square wave with a maximum bandwidth of 3MHz (for each sample 2 32 bit words are transmitted so for CD (44.1KHz) the bandwidth is 44100*64 = 2822.4Kb/s) - now at the receiver only 200mV is needed to be considered a logic high or 1, that's a tolerable 80% voltage loss! I reckon any half arsed cable (75Ohm) can do that, and you'd soon know when it didn't as you'd get pops and squeeks etc!

maybe you can argue directional cable in the digital domain - it's digital (ie 0 or 5V) not AC lol :tony: (i'm not condoning it btw )

Somebody make a couple of truly directional cables (ie diodes in series with signals) that should soon convert these "directional cable converts" - mmmm half wave rectified music...

The process we are discussing is digital(electrical) >light -light >electrical(digital) >analouge...as the medium is digital. Although technically co-ax should be better, in reality, when using a high quality DAC, the difference is inaudible. WHat makes a good DAC is ability to handle jitter, and although the optic stage *may* introduce more then using co-ax in theory, that doesnt mean you can hear it or the amount of jitter is significant. If you are running a pro studio then you wouldnt use optic and no one does but in a car optic is immune to noise and any system using an outboard DAC, is usually of high enough quality, that any advantage co-ax may have technically, would end up being a perceived advantage not actual.
peace
Cyberpunky

That is the best and most accurate answer !

Theorectically Co-ax is better. That's what I said.

Can you here it??

Let alone hear it in a moving vehicle??

OF COURSE NOT.

I was poking fun at the whole thing, $1000 "directional" (ie analogue) RCA cables and all.

Phil

Thanks Angelo

Phil...my post wasnt directed at anyone...just wanted to clarify the reality of the situation before it went too far off on a tangent
peace
Cyberpunky

Theoretically the two are equal. Well not really optical is actually superior. It has the advantage of not introducing the possiblility of a ground loop and being able to run much longer distances.

The people who make up the crap about optical connections do not have a clue. Usually the same people who think CDs are a digital device.

Jitter is not caused by the phodiode.
Correcting jitter with the DAC will solve the jitter problems wether a coaxial or optical arangement is used, its a non issue.

It's the process of going from electrical to light and back again that makes optical inferior.

More processing = signal decay, regardless of how good the the gear is.

As we've said already, you'd never hear the difference in a moving car. This discussion is purely academic.

Phil

There is nothing inferior about going to and from light.
Maybe the lack of knowledge is yours in respect to lasers and photodiiodes.

Signal decay what is that???????
This is a digital domain- you either get the signal or you don't, there is no such thing as decay or jitter problems (they are something VERY few people understand).
If anything the optical is superior, it provides no ground loops, it doesn't have to worry about the impedance mismatch that is present with the coaxial cable arrangement (there is quite an impedance difference).

The less processing the better. The fewer components in the signal chain the better.

I'll say it again, this discussion is purely academic, you simply can't hear it in a moving car.

Phil

i thought the optical Vs coaxial debate was more over a syncing problem between optic transmitters and receivers.

and then you've got the coax vs balanced (AES/EBU) argument....

there's competition between coax and EBU, EBU is superior by design

yes