Sound quality problems

[Haydn]

Hello all,

As promised, here is some feedback on my sound issues following the latest club night this Tuesday. It's in a small downstairs bar.

Firstly, I learnt that the input into the amp is 'unbalanced'. I'm not quite sure why - either because it's a cheap setup, or possibly because the sound goes through a noise-limiter. The speakers are fairly small and cheap-looking, which also suggests a cheap set-up. The input cable presented to DJs is a pair of RCA connectors. I was going to connect these to the XLR output on the back of the CD Mix 2, but realised I'd brought the wrong cable. The XLRs on the CD Mix 2 are male, so I needed female, but of course I had male. Oops. So I connected from the RCA outputs on the deck, just as I had done the previous week.

I did a sound check using track 12 'Silks and Satins' from 'The Complete Atomic Basie'. I compared my CD Mix 2 with my friend's Pioneer single deck and mixer. His sounded better, but mine was acceptable, and as his was only a single deck, I decided to use mine.

I also learnt that there is a problem with the CD Mix 2. If I turn the Master fader right up, it makes a hissing noise (this is with no music playing). Master fader right up and Channel right down - hiss. Channel right up and Master right down - silence. Master and Channel both right up - hiss and added treble noise. By comparison, my friend's Pioneer deck and mixer were virtually silent when turned right up. My Numark made the same noise at home, when using the XLR or RCA outputs, so it's either a general problem with all CD Mix 2s, or perhaps just a problem with this one (I bought it second-hand on eBay). I've also noticed there is a 'Ground' screw connector at the back for grounding turntables etc. Could connecting this to something help? I don't think so myself. I remember grounding helps get rid of humming noise but not hiss.

The previous times I'd DJ'd with the CD Mix 2, I'd had sound problems, and I'm sure having noise from having the Master level up high was a big cause. If I turn the Channel volume up and keep the Master down, the hiss is much less that the other way round, so that's what I do now.

I also noticed how much easier it is to get modern track to sound good. For example, 'Wade in the Water' always sounds great, but it's a lot harder to get Duke Ellington tracks from 1940 to sound good. I find this at home, and in this club. On Tuesday, the modern music also went down better with the crowd than the old stuff, but I think this was more due to musical preferences than sound quality.

• Conclusions

1. The sound system in the bar seems to be a low-quality set-up.
2. My CD-Mix 2 has a noise problem.
3. I think my previous problems were caused by both my CD-Mix 2 AND the bar's sound system.
4. Modern tracks are less affected by sound problems.

I'm probably going to carry on using the CD Mix 2 in this club for the moment, keeping the Master volume down. I'll get the right cable to use the XLR output from the deck because it might give me more volume and therefore flexibility. I'll have a preference for modern tracks when I use this equipment (but I'll take dancers' tastes into account).

There's a separate issue about DJing in this club, which I'll start another thread on.

[Bob the Builder]

I’m sorry Haydn, to hear some of the problems are not solved.

Regarding the “hiss” out of your system. It is very common. In many mixers you can expect to hear a hiss if you push the volume up over 8. Good mixers are obviously better, but having the money to spend on good mixers does not often come into the Swing market.

Just in regard to cables. Because of your setup (unbalanced), the benefit in going to XLR, will be very, very small in comparison to RCA. Just don’t spend to much money.

Brian

[Haydn]

** Update **

I've discovered that one of the two RCA outputs from the Numark CD Mix 2 isn't working. The XLR outputs both work, so I'm going use them from now on. Incidentally, it wasn't obvious that one of the outputs wasn't working, because most records are either mono or have little stereo separation. In fact, it was only when I played a modern stereo pop record that I realised one of the stereo channels was missing.

I think the fact that I was playing from only one stereo channel might have affected the sound quality though.

[Haydn]

Just updating this for reference and possible value to others.

Last night at the bar, I found that the problem is not quite what I thought. One of the two output channels disappears, but comes back if I push in the back of the case next to the XLR outputs. This has the same effect whether the ouput comes from the XLR or RCA sockets. At home earlier, I must just have been lucky that both channels worked when I connected the XLR outputs. That made me think it was the RCA outputs that were faulty. But it actually seems to be a bad connection inside.

I managed to tweak it so that both channels worked last night. The good news is the sound quality was far better - most of the hiss and distortion seemed to disappear. But the volume was also much lower than it had been on previous weeks - I don't know why this was.

My plan is to complain to the eBay seller who sold me the CD Mix 2 (as it seems that he sold it with this problem). I'll also see if I can fix the problem. But in all likelihood, I'll probably end up buying a new unit