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Hi guys,

I own an SQN 4-s early series mixer. I have been experimenting with the mixer prior to a shoot where I will be using the mixer to send audio to the camera. Basically I am using the mixer with a boom and two Radio mics on channels 1 and 2+3 respectively.

Using the tails I am sending my output into my 702 and monitoring the signal on return to the mixer. Now, I have set up the line up tone at -20d and continue to monitor the signal that is returning from my 702. (In other words, the 702 is replacing the camera for experimentation purposes). However, as I switch from monitoring the return feed from the 702 and the actual input into the SQN mixer the two signals sound quite dramatically different. The return feed from the 702 is thin and lacks the bass in the signal I am getting monitoring the signal in the mixer.

I have checked all high-pass filters, headphone volumes, limiters etc on both devices.

My suspicion is that the outputs on the old SQN are simply not very good. Does anyone else have experience of this? It seems odd the outputs on the tail are not of great quality as this is obviously the main purpose of the mixer.

Any help much appreciated :)

Cheers,

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  • Thanks for the quick responses. Yep i'm using it with a multipin out in this case, I get the same kind of quality on the XLR outs too. A few people have suggested phase too, but I notice the effect on just one channel. Having played around a little more it's perhaps not just as dramatic as I first thought. I've been switching back between the 702 and the SQN and perhaps it is more of a question of taste between these two devices sounds? I'll try and record an input from each and post them up here soon. Thanks again guys. Jul 15, 2013 at 22:07
  • have someone take a look at it. this is strange behaviour. Jul 16, 2013 at 10:53

5 Answers 5

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have you tried monitoring directly from the headphone output of your 702? Bear in mind that most headphone output are unbalanced signals, and depending on the wiring of your return cable, that may be causing some phase issues.

On the other hand, I have the same problem whenever I take a return and run it through a separate headphone amp instead of the returns of my SD mixers. Its a major difference like what you have described and I never really figured out why.

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Curious, this type of mixer is sturdy and doesn't start acting up suddenly (in my experience at least). What do you mean with 'tails' is that the multipin output on your mixer, with the screw on plug? If so, have you tested the XLR outputs? How do they sound? Also can you listen to both outputs without the SD702 in between?

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If the bass is lacking, then it sounds like there's a phase issue, i.e. a false connection or bleeding of channels. Quite unexpected though and not something I'd consider a feature of "a bad quality mixer".

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Maybe a phasing issue between radio mics ?

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As a long-time owner and pro user of an SQN4S there are a number of possible issues. The most likely is a damaged or shorting Hirose 10-way cable. These regularly cause problems unless very well maintained. The Hirose plug shell locking screw works loose, then the shell rotates causing the 10 internal wires to short or fracture. The usual solution is to carry a spare 10-way lead (I used to make my own). Secondly the usual "tails" you speak of can be made up in several configurations, but the most common for use with a pro video camera is Hirose 10W to 2 x male XLR + stereo minijack audio return from the camera. Note the 3-core minijack return is unbalanced and should not be fed back into a balanced input. The tails can also have the same cable damage, spares should always be carried, I have several sets. I read that you mention tone at -20d, I assume you mean -20dB? The SQN and the SD702 are very different machines, the first is 30+ years old, analogue, with probably (there were several variants) BBC-type PPM meters with totally different attack and decay profiles, made in the UK. The SD702 is relatively new, almost all digital, made in the USA, with SMPTE digital meters. Try bypassing the Hirose 10W connectors and feed L+R XLR cables from the SQN to the SD702 inputs, preferably at line level. Set the SQN tone to PPM4, in stereo if available. Adjust the 702 input levels to read -20dBu (the American standard) or -18dBu (the European standard). Check you have good clean audio at the 702 headphones. Check with a mic connected to the SQN that all sounds good. If it does, the problem is almost certainly in the 10w cables. A very likely cause is that the audio return part of your tails has been incorrectly wired and you are getting L+R phase cancellation which would sound very 'thin' and lacking bass. SQN are very helpful with repairs or wiring diagrams. Repair them and try again. Forgive the long answer if I am covering details you already know, but sometimes the answer can help someone else as well.

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