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Do external word clocks make a difference?


Mark Payne

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So

 

Next Weds 2nd May in the eve we have respected audio engineer Tree Tordoff from Yamaha comming to test our ears!

 

We will be Myth Busting! Do external word clocks make a difference to perceived audio quality?

 

All digital audio systems are dependent on good quality wordclocks; a better clock gives better sound doesn't it? With careful listening tests and some measurements we will explore this controversial subject and you get to decide. / Bring your ears, This is going to kick off!

 

Our seminars are free. You turn up, we have fun looking at cool audio stuff and then we drink beer. It's very simple!

Register here

 

http://www.sflgroup.co.uk/Groups/190072/SFL/Training/Wednesday_Evening_Seminars/Wednesday_Evening_Registration/Wednesday_Evening_Registration.aspx

 

We start at 7:30PM so arrive at 7:00PM. We normally finish the seminar around 9:30PM for a beer in The Hub.

Please do register as it helps me to keep track on numbers.

 

See you next week!

 

Cheers

 

Mark

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I can't make this, but I'd be interested to hear what your proposed method for the test is - will all listening be blind?

 

(I'm fairly convinced that external clocks make no difference btw)

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I can't make this, but I'd be interested to hear what your proposed method for the test is - will all listening be blind?

 

(I'm fairly convinced that external clocks make no difference btw)

 

We will be doing double blind "A B X" testing.

 

You Hear A

You Hear B

We then show you X (and you don't know)....

We repeat...... A, B, X

 

Now you have to say what X is (is it A or B?).

 

This will mess with your head!

 

Regards

 

Mark

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Yeah, it's a bit far for me to commute as well (though your mention of beer makes it tempting).

 

However, I've had SO many arguments about this, I'd love it if you'd post your findings. Well, unless you find there IS a difference than you can keep as quiet as you like so I don't have to eat humble pie!

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Bit far for me, but let us know the result.

 

Maybe do another test carrying the clock signal down a coat hanger (as long as the coat hanger's characteristic impedance is about 75 ohms, it shouldn't matter!)

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So

 

Next Weds 2nd May in the eve we have respected audio engineer Tree Tordoff from Yamaha comming to test our ears!

 

We will be Myth Busting! Do external word clocks make a difference to perceived audio quality?

 

All digital audio systems are dependent on good quality wordclocks; a better clock gives better sound doesn't it? With careful listening tests and some measurements we will explore this controversial subject and you get to decide. / Bring your ears, This is going to kick off!

 

Thanks, I've been meaning to do that test for years. We will all be enlightened. Say hi to Tree for me.

 

Mac Kerr

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Looking forward to this.

 

Not just because I, and many other engineers hold an opinion on this topic that is essentially based on 80% theory and 20% actual experience and 0% true ABX testing (partly because this is tricky while on a job!), but also because there are 2+ questions here:

 

1. Does it make a difference?

2. is it better?

3. How do we objectively define 'better', as opposed to 'different'?

4. If it does make a difference, and it is 'better', why the heck wouldn't every console manufacturer spend the extra couple of hundred £ on a better clock? It would be the simplest whole-system upgrade ever!

 

I would definitely say that I have been in an A/B testing scenario where I have absolutely heard a difference, but whether it was better or worse really came down to opinion. Those with me were quick to say it was, but I suspect they were looking for one. I didn't really like one better than the other, but it was different.

 

Anyway, very interesting stuff and looking forward to the testing!

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So

 

Next Weds 2nd May in the eve we have respected audio engineer Tree Tordoff from Yamaha comming to test our ears!

 

We will be Myth Busting! Do external word clocks make a difference to perceived audio quality?

 

Cheers

 

Mark

 

Bueller... Bueller... Bueller?

 

Mark, any results that you can share with the class? Inquiring minds want to know.

 

Mac

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Did noone but SFL attend this, or something? red faces all round indeed.

 

Hey guys,

 

 

You missed out on areally good night when Yamaha came to SFL to demonstrate their theories on wordclocks. There were quite a few of us there all eager to form a conclusion onthe issue. If the advocates for word clocks are right and all it takes is theaddition of a Big Ben to an M7CL to make it sound like a XL4 (a little exaggerationin there) then it would be a win win for everyone. We all approached it openminded.

 

 

Tree Tordoff and Andy cooper from Yamaha were therehaving spent the last year doing R&D into this whole area. They had come with a lot of informationand evidence to prove that this idea is more myth than fact.

 

 

They did two denominations to show the grounds forthe argument:

 

The first was to showweather an external word clock generates more jitter than an internal one.

 

 

They produced a 10kHz sine wave, then notchedit out and raised the volume by 70dB to hear the resulting noise caused byjitter. The experiment showed thatwhen there is no input signal, jitter has no audible effect. When thereis input signal, particularly at high frequencies (where the audio wave ischanging shape rapidly), the effect of jitter can be seen and heard. Using an external word clock source increases the amount of jitter because of theeffect of the PLL (phase locked loop) filter inside the mixer. The PLL isneeded to reduce the destructive effect of dirty clock sources, but italso inhibits the effect of a clean clock source.

 

Despite the extra noise that is caused by anexternal clock source, with a real-world type of music source, with a sensiblegain structure, no one can actually hear the difference: the jittereffect is around 90dB lower in level than the original sound. So thejitter noise is effectively masked.

 

The second test was a listening test between anaudio signal running through a two different LS9s; one using its internal wordclock, the other an Apogee Big Ben. They had spent a lot of time setting it up so there was no level changebetween the two set-ups. They wereidentical. The big question, couldwe hear a difference? NO!!! Everyone was listening intently,wanting to hear a difference between the two. It is more of a placebo effect than an actualdifference. Some people felt theycould hear a minute difference on the end of a reverb tail on one of thesongs. Personally I believe ifyour listening hard enough you can convince yourself of anything. If you want it to sound better, itwill. If the placebo of having onemakes you listen more intently whilst mixing, then that in turn will improveyour mix. But its an expensivepiece of equipment to have solely to make you concentrate.

 

 

Finally, a great plusto end the night was the arrival of SFLs new CL5, the first one in the country.We all got the chance to play, Yamaha have upped their game! Very exciting.

 

 

Please feel free todisagree with me on the subject, its just my opinion.

 

 

God Bless,

 

 

Mark Sunderland

 

 

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