Welcome to No Limit Sound Productions

Company Founded
2005
Overview

Our services include Sound Engineering, Audio Post-Production, System Upgrades and Equipment Consulting.
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Our mission is to provide excellent quality and service to our customers. We do customized service.

Friday, May 26, 2017

Q. Why don't my synth basses sound good on a hi-fi?

I'm mixing a project which has a number of synth parts that sound great in my studio, but I've just been listening to some rough mixes on my home hi-fi system and things are not good. Firstly, the sounds go very low and are quite bass-heavy, and they distort my normal hi-fi speakers despite coming over great on my studio monitors. Also, some of the instruments just do not sound like they do in the studio. I'd go so far to say that lumps of the sound just aren't there on the hi-fi.
How should I deal with these sounds? My studio speakers (HHB Circle 5s) probably go down to 45Hz, but my hi-fi only goes down to 65Hz and I can't assume a listener will have studio-class monitors or a subwoofer, so I need to tailor the mix so it translates on a range of systems. But I don't want to lose my sounds!

My room has no fewer than six bass traps, and splayed walls and ceilings, so I can't see that it's a room issue. Besides, normal mixes of acoustic/rock music translate fine. In case it's helpful, my music is mostly electronica.

SOS Forum Post

SOS contributor Mike Senior replies: Given that acoustic and rock music already translates pretty well, I think the problem is likely to be to do with the way your monitors are dealing with sub-bass frequencies. Acoustic and electric bass instruments are unlikely to give the kind of powerful fundamental frequency to each note that a synth can, so the capabilities of your monitoring in this area may not have been pushed particularly hard until now.
Stuffing ported monitors (HHB Circle 5s in this case) with socks or fabric will attenuate low frequencies emitting from the cabinets. This will make their output bass-light, but you'll be able to judge the low-mid frequencies better as a result.  
Stuffing ported monitors (HHB Circle 5s in this case) with socks or fabric will attenuate low frequencies emitting from the cabinets. This will make their output bass-light, but you'll be able to judge the low-mid frequencies better as a result.

For a start, I wouldn't assume that you have no room problems in your control room, despite your acoustic treatment. Your room design and bass trapping will be helping matters, but it's phenomenally difficult to control the frequency range below 50Hz, so you are still likely to have some sub-bass unevenness around the room. For this reason, I'd at least stroll around the room a little when comparing your sub-bass levels against suitable reference material, as this may help give you a more average view of the levels.

Room modes are only one thing that could be causing you problems. Unless you have your speakers on solid stands, sub-bass may be wobbling the stand about and affecting the low-end response. The heavier and more well-rooted your speaker stands are (and the better the speakers are stuck to them) the better your bass accuracy will be. Using speaker-stand spikes to get through carpet, filling hollow speaker stands with sand, and putting non-slip matting under your speakers are all tactics that can help. Also, if you have a boarded (as opposed to concrete) floor, then it could easily be resonating at low frequencies, as could any large furniture surfaces, affecting the perceived sound.

The ported design of your monitors may also be a partial culprit here too. Although porting is often used by manufacturers to increase the bass output of smaller speakers, the side-effects of the port resonance can make mixing bass instruments a real nightmare. For a start, the port's main resonant frequency is probably around 35-40Hz, and anything at this frequency will ring on quite dramatically. The resultant length changes make it very difficult to judge balance. Another side-effect of the port is a very steep roll-off below the port's resonant frequency, and I think this might be encouraging you to use too much sub-bass. I'd guess that the distortion you're getting through your hi-fi is a result of its consumer-grade amplifier struggling to cope with lots of inaudible sub-bass.

The ports on the Circle 5s are also rather slot-shaped, which is likely to produce a fair amount of turbulence (and therefore noise) which will tamper with your perception of sub-bass volumes. Then there are low-frequency compression and distortion effects from the port as well, which could lead you to think that your synth sounds have more low mid-range than they actually do. Given that bass sounds are primarily audible from their low mid-range on smaller speakers, that's probably part of what's making the comparison of your studio and hi-fi monitors confusing. There's also the fact that your hi-fi speakers are almost certainly ported as well, but at a different resonant frequency, which doubles up the problems...

The real question is, how can you work around all this? Well, I've already alluded to walking around the room and referencing against commercial material for coping with room modes, but there are other things you can try too. For a start, try running the sine wave sweep file from SOS January 2008 (www.soundonsound.com/sos/jan08/audio/sinesweep.mp3) through your Circle 5s at a realistic volume, because it can reveal a surprising number of things.

First of all, if you look at the speaker-cone excursions, you'll almost certainly find that they start quite wide, then seem to get narrower as the tone frequencies rise, before widening out again. The excursions narrow the most at the resonant frequency of the port, and this frequency will be where the port-related problems are likely to be most problematic when mixing. If you can begin to get a feeling for how the port resonance sounds, you can go some way towards mentally compensating for it when you're mixing.

The sine tones will also give you an idea as to whether you still have room-mode problems; any level peaks/troughs will be pretty clearly audible. Plus, sine waves are so pure that floor or furniture resonances and port noise will show up much more starkly than when listening to complex music.

Another tactic I'd try is occasionally blocking your monitors' ports with a pair of old socks, or a J-cloth, as is being used in the example above left! This'll probably give you a rather bass-light sound (the speaker's frequency response was designed with the port's bass boost in mind, after all), but I have found that with a lot of ported monitors it also makes the balance of bass and mid-range frequencies much easier to judge reliably.


Published March 2008

Tuesday, May 23, 2017

Q. Do you have any soldering advice?

I have a vast amount of mic cable and a load of three-pin Neutrik NC3FX female connectors ready for soldering (there is no need for male connectors as the other ends are going to my patchbay). I've done a limited amount of soldering in the past and just wondered if there were any handy tips? I've got all the tools, including a 'desolderer' and a multi-clamp to hold things in place.
SOS Forum Post
It always helps to tin any wires before soldering joints. Use a little solder on the twisted strands to lightly coat the wire. 
It always helps to tin any wires before soldering joints. Use a little solder on the twisted strands to lightly coat the wire.

 Make sure that your connector is securely fastened in a vice or clamp to stop any movement while you solder. 
Make sure that your connector is securely fastened in a vice or clamp to stop any movement while you solder.

 Leave any mistakes to cool before using a desolderer to clean the joint of any old solder, and then start again. 
Leave any mistakes to cool before using a desolderer to clean the joint of any old solder, and then start again.  

Technical Editor Hugh Robjohns replies: Wiring XLRs is one of the easier DIY challenges to tackle once you have a little experience under your belt. The solder contacts are large and fairly tolerant of over-heating, while cable trimming and dressing aren't too critical either. It's a good way for novices to get started and build their confidence in soldering and cable preparation.

The first step is to thread the cable through the strain-relief collar. It's immensely frustrating to have to unsolder a perfect connection just to put the collar back on, so don't forget! If you're planning to use slide-on cable identification markers, then put these on before the collar.

With the cable threaded through the collar, strip off the outer sheath and prepare the individual wires. It's best to use a proper wire stripper for this, and it's a good investment to buy the best self-adjusting type you can find. Using the wrong tool could damage the insulation and/or nick the wires. The former risks short circuits, the latter risks breakages and open circuits.

With the wires trimmed to an appropriate length and stripped, it helps to 'tin' them. Twist the strands tightly together, heat each wire, and feed in a little solder so that it flows and coats the metal. Don't get it too hot, though, as the insulation is likely to melt or shrink.

It's good practice to then introduce some insulation sleeving over the screen wire, to prevent short circuits inside the connector body. You can buy bags of pre-cut rubber sleeves that make the job neat and tidy, and they also allow for easy re-working if you need to repair the connection at a later stage. Heat-shrink sleeving can be used, but makes the job of repairs slightly more difficult. Also, at this stage, decide which of the two core wires will be denoted as 'hot' and which as 'cold' — make a decision and stick to it!

Next, fix the connector into a small vice or multi-clamp in such a way that allows you to access the three pins, and then tin each of them. If you don't have a vice or clamp, then you could use a cable tester, or a similar device (the heavier the better to stop things moving around too much while you are working), as long as the connectors are fitted somewhere convenient. Also, I find it helps to point the female end of the connector slightly uphill, otherwise the solder disappears inside the terminal!

Identify the pin numbers (these are usually embossed beside each pin on both the inside and outside of the connector) and remember that the male and female connectors are mirror images of each other. For that reason, it makes sense to wire all the connectors of one sex first, and then all those of the opposite sex. If you alternate between wiring male and female connectors, it is inevitable that you will end up wiring at least one backwards!

Once you have correctly identified each pin, offer the 'cold' wire from the cable to pin 3 (it's the the one in the middle). Hold it steadily in place while you heat both the wire and the terminal, and then feed in some solder. As soon as the solder melts, remove the heat and hold everything still until it cools and the solder sets — it should be just a few seconds.

The key is to be be as quick, clean and precise as possible. Don't keep jabbing at the solder joint. If it isn't right, do the next joint and come back to any problem later once it has cooled. Use the solder-sucker (desolderer) to clean the joint of any old solder and start again.

Repeat the process for the 'hot' wire on pin 2, and then the screen wire on pin 1. I don't recommend linking pin 1 to the connector shell as it usually causes more trouble than it's worth, but there is a central tag for that purpose if you should require it.

If you're happy with the solder joints, fit the plastic insulation and cable clamp sleeve. Slide the whole thing into the metal shell (being careful to align the rib and notch), ease the release button into place and screw the end-gland up tight. Always test the cable to make sure that it's wired correctly (with particular attention to pin 1/pin 3 reversals). In the case of patchbay wiring, it pays dividends to label the cable ends in some meaningful manner, making it easier to replug things later.


Published June 2008

Saturday, May 20, 2017

Q. Can I spray-lube my crackly pots?

I've got a problem with one of the gain knobs and both of the bass knobs on my Rane TTM56 DJ mixer. They've been used quite a bit over the last couple of years and have recently started crackling whenever I adjust them in any way. Usually, if I'm getting bleed or crackle from a fader I'll use some sort of spray lubricant, like WD40, but I'm not sure if this will work with EQ knobs. I've often heard people mention contact cleaner for use with connectors, so I assume this kind of thing could work for my pots? Has anyone had similar problems, and if so could you offer any advice?

SOS Forum Post
Caig's Deoxit D5 is a contact enhancer that's an excellent choice for cleaning connectors, as it improves conductivity and — unlike many other lubricants — doesn't leave a sticky film. Deoxit can also be used on crackly pots, and while it won't actually restore them to full health it could buy you some time while you look for a replacement pot. 
Caig's Deoxit D5 is a contact enhancer that's an excellent choice for cleaning connectors, as it improves conductivity and — unlike many other lubricants — doesn't leave a sticky film. Deoxit can also be used on crackly pots, and while it won't actually restore them to full health it could buy you some time while you look for a replacement pot.  

Editor In Chief Paul White replies: We get a number of enquiries as to the best way to clean faulty socket contacts or crackly pots, and there are many commercial contact cleaners available. However, you should be aware that most ordinary contact cleaners have a greasy base and tend to leave an oily film on the surface being treated. So, although you may notice an improvement in the short term, you often find that dust builds up on the sticky surface and may eventually make the problem even worse than before. Most connector contacts can be cleaned to some extent by repeatedly inserting and removing the connector (Studiospares market an abrasive dummy jack plug that does the job more effectively), although the normalising contacts found in patchbay and insert point TRS jacks aren't in direct contact with the plug, so they don't tend to respond to this treatment. My preferred treatment for awkward connectors is to use Caig's Deoxit D5 spray, a contact enhancer that reacts with the metal surfaces of the connectors to improve conductivity, but without leaving a sticky film. You can also use it, sprayed onto a cloth, to wipe jack plugs clean as part of your routine maintenance. Avoid getting it near the capsules or internal electronics of capacitor mics, though, as it can compromise the operation of the extremely high impedance circuitry used there. Almost every large music store in the US stocks Deoxit, but in the UK you may have to order it from a studio supply company or track it down on the Internet.

Compressed air can sometimes remove dust that may be causing a pot to be crackly. However, the problem may not be dust: most pots have a carbon-based resistive track, and the action of the metal wiper contact eventually wears away some of the carbon, which can also generate crackling. If you use a cleaner/lubricant spray on a badly worn pot this carbon can mix with it, to create a greasy carbon-dust sludge. In the long term, replacing the pot is your best option, but a spray of Deoxit D5, or even off-the-shelf contact cleaner, may buy you some time. You need to be able to get to the back of the pot and spray into it where the three contact lugs exit the casing, so the flexible tube that comes with these sprays is useful here. Don't try to spray the top of the pot, hoping some will run down the shaft and into the mechanism, because that part of any pot is pretty well sealed.

Finally, a lot of dust-related problems can be avoided by covering mixing consoles and patchbays with cloths when not in use.


Published July 2008