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Topic: RCA, 1/4", Universal/Line sound connections performance matters - Page: 1

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Im evaluating audio interfaces in order to improve the sound outcome. Some Audio Interfaces like NI A DJ 8 manage RCA outputs and inputs, others like echo audiofire pre 8 manage 1/4" outputs, and Universal/line inputs and so on... i ask you people, in your experience, is there a noticed difference in the sound quality using one connection type from another?

Of course the brand and technology that each AI is made matters more... but when you have 2 similar audio interfaces (like mentioned), Does the type of connection matter?

thanks
 
geposted Mon 26 Oct 09 @ 11:39 pm
Tell us about your current set up, like what type of players you are using, CD players, Vinyl, or MIDI/HID. I am guessing you are using a timecode setup? What type of interface box is it that you have, or is that what you inquiring about?

Your post was a bit ambiguous to me, mainly because I like knowing what I'm working with before dispensing a quality response (if I have one!). An educated guess is still nonetheless a guess!!


DJ RuDe


Keep Spinnin'!!
 
No big deal... i just bought The Vestax vci-100 Midi Controller, 4 Mackies HD1531 15IN 3-Way 1800W Powered Loudspeaker and 4 Cerwin-Vega CVA-121 21" Active Subwoofer, everything running with a MacPro @ 2.8 Ghz, 500 HD @ 7200 RPM with Snow leopard. The only thing that miss is the Audio interface.
I'm interested in the Echo Audio Fire 4, 300 USD (FireWire), (Outputs: 4 1/4" & Inpusts: 2 Univesal and 2 1/4"). In the other hand the NI Audio DJ 8, 400 USD (USB) ( 4 RCA Inputs, and 4 RCA Outputs).

Of course in the future i would like to add TC, and other devices.

I want to achieve the best sound quality possible given the spekers and Subs and do not regret, since the Audio Interface is an important player in that.

thks
 
You’ll generally not notice any audio quality difference between RCA & ¼” jack (TRS) connections. RCA connections carry a positive and ground signal only (unbalanced, -10dBv). ¼” jacks usually carry a positive (hot), negative (cold) and ground signal (balanced, +4dBu).

RCA are not considered Pro connections because they’re prone to pick up hum and/or noise if used over long distances (~>20 feet or so) or near power cords, and carry a lower signal. The cold signal in a balanced cabled is inverted at the receiving end of the connection and applied to the hot signal, effectively cancelling any electromagnetic interference picked up along the cable.

You’re usually better off using ¼” jacks if possible.
 
Also, over a longer length of cable the RCA cables can allow some interference. Which is why most pro apps run either 1/4', banana, XLR or Speakon connections.
 
thanks guys...everybody here told me that was the same and was insignificant use one or another type, and i'll see, is not insignificant. So i will go then with the Echo Audiofire 4 o the Echo Audiofire pre 8 since the outputs are jacks ...

For those who are using the NI Audio DJ 8 (Just RCA Connections), be careful, could be loosing sound quality.

I'm not technical... what implies and mean unbalanced (RCA) or balanced (jacks) signal? and -10dbv (RCA) +4 dBv (jacks)?
 
Hi mate.

A balanced system use 3 conductors/wires, one has a positive or unchanged signal, one carries the same signal but 180degrees out of phase (or inverted/opposite) relitave to ground and the other is a common return. The reason for this is that over longer cable lengths any noise or unwanted signal picked up by the cable will be introduced at the same time to the non inverted and inverted signals and so is naturaly canceled out. Leaving the origional, wanted signal noise free.

The balanced system is usualy used with 3 pin XLR or TRS (TIP, RING and SLEAVE) 1/4 inch jack. Some studio equipment also uses TRS Bantam connectors (once used in the telecom industry) these look similar to 1/4 inch jacks but are of a smaller diameter and ar not compatible with standard Jack plugs/sockets.

Balanced line systems are most importent when used with very low level signals ie microphones 2 - 5 mV. Over short runs say 3mtrs or so and using line level 100 mV or higher the advantage over a non ballanced system is less as the wanted signal level is already much higher than any unwanted noise.DJ Mixer inputs and CD player outputs for example are not generaly fitted with ballanced connections as the cable lengths used are very short and at line level. Some of the better mixers are however fitted with XLR ballanced outputs as the cable lengths involved between Mixer and Amp can be quite long.

The -10 and +4 db refers to diferent output standards used in the industry to allow the maching of audio equipment. Typical difference would be a domestic HIFI product outputs arround 100/150 millivolts -10db. and pro audio mixers will output 1-2 volts. It is actualy a logarithmic mesurement of power but the reasons for this and how its calculated can be a bit involved.

Daz
 
Thanks Daz... Very interesting... so if i understand well it depends how far my speakers and amp will be located, in my case is the same since they are PA speakers, in the other hand i have to check the output signal of the Audio Interface right? or the signal level depends in the volume sent to the speakers?...or how does it work exactly?
 
Hi mate.

You will normaly find that DJ mixers are capable of operating over a fairly wide range of input levels and many have pre fader matching, or gain controlls. These allow you to cover for most of the input equipment you will come across. The gain controls are used to set an initial level on the mixer to match the equipment you are useing. The signal from the gain control then gets fed to the faders on the mixer. This allows you to get a good range of level control on the fader. For example: gain too high=high volume with the fader just of its lowest stop / gain too low fader can be moved to the top but not enough volume is output.

Most DJ mixers again provide for a wide range of output levels and provide a master output control to allow matching to the amplifier being used. You dont need to be technical about it just start with a low level setting on the mixers master output. Work your way up. If you are feeding into a HIFI amp very little movement is needed as the HIFI amp will produce its maximum output from a fairly low level signal. Feeding PA amps the master output will be higher in order to match the higher level signal that the PA amp requires to produce full volume.

If your mixer has an output level meter this only gives you information on the output signal level relitive to the mixers designed output range and this is where the db thing comes into play. Output meters are marked in db (decibells) most will have at least a green and a red set of LED's the colour of the leds helps to indicate the point where the mixers output is correct or what is usually shown as 0db. running the output above this point risks distortion so if the red lights start to come on back the volume down. Again most PA amps and Active speakers have some form of level control and many have the same style of level meter as the mixer. This helps allot because you can set the mixer to produce an output of 0db on its level meter then set the amplifier to do the same on its level meter. then you know that what ever the mixers meter tells you is a true indication of what your amplifier is actualy doing. This will help you avoid distortion and speaker /amp damage.

If you are using active PA speakers (ie speakers with a built in amp) then The balanced system is most usefull as you do not have to worry about how far away your speakers are from your mixer. Obviously your mixer needs to provide for balanced outputs so check before buying because not all do.

As far as your interface goes the distance between the interface and amp or interface and mixer will be the decider here. Again be aware that although some interfaces provide 1/4" jack outputs not all are ballanced, some are just single ended using mono jack plugs. This is no problem if you are looking to use an external mixer between your audio interface and amp but if you will be using a combined mixer/controller and connecting the interface directly to your anp/speaker setup, look for an audio interface that provides for balanced outputs. BTW a balanced output is automaticaly converted to a single ended output if you use a mono or TS jack instead of a TRS (looks like a stereo headphone jack)

Daz
 
the echo audio fire 4 manage 1/4" jacks outputs (http://www.echoaudio.com/products/Product_Comparison_Chart.php). In my case i will use the vci-100 as the midi-controller, but who will manage the power signal is my audio interface which will be the "mixer" that your'e talking about right?, but im not pretty sure if this audio interface manage the green and red leds you're referring... the explanation that u gave is understandable if i use the e.i. herciles rmx, but when the midi and the sound card are separated like my case which one take the control of the signal?... if my logic is not wrong the midi in this arrangement is just a interface to manage the functions and features of the DJ SW i'm running, and the Audio Interface (echo) will manage the power signal that is supposed to be managed by the SW provided with the Audio Interface right?

sorry is a little bit confusing to me...
 
No problem my friend.
Using the system you have described I have placed an answer to your outher post on loudspeakers which should help. 0db in your case would be the point at which the level indicator bars on the VDJ skin are just touching the top ocasionaly.

BTW I notice that you are a limited edition user. Check on the fetures list for your software to make sure you can run an external multi output audio card as this may be one of the limitations on your software version.

Daz
 
yeah i just answer and read your advises, i appreciate it.

i will take my chances and buy the pro version when my equipment arrives. I hope that my purchase could help to Dev team to release a mac demo version in order to taste the SW for who can not. I will make a semi-blind buy since i don't have pc and just have tasted the limited version and i couldn't run all the functionality of the SW like the pc users do, i wish no regret even the video issues that the mac users are concern.

isra
 
This is the reason that I harped on about using a midi controller in conjunction with a mixer and not as a replacement.

Phono or jack to jack from a midi controller or sound card straight to the speakers just won't do in my opinion. XLR is the professional option but you can only do this by having a mixer or by finding a sound card that supports this connectivity.
 
I don't think you shuold be blind buying anything mate!

As Charlie sais. By far the best way to do this is to use a controller to operate the software and a multi channel sound card/mixer combination.
If you have not already purchaced the vestax, take some time to look at this combination. Good and now not expensive controllers would include Numarks DMC-2 for example. Mixers are available with built in sound cards but for flexibility look at keeping the mixer and sound card seperate.

Please take your time. You are about to spend an awfull lot of money so make shure you do it right!!!!!!!!!!

Daz
 
mmm... Daz just said, that given my active set up, the best option is the TRS connection (1/4" jacks).

Since i didn't found a supplier in mexico and the only one authorized in the states is not available any more about the studiomaster PW-mixer that u recommend me, i decided to buy the echo audiofire 4 which has 4 1/4" outputs that recommend me acw_dj to improve the sound quality since the quality of the soundcard of the rmx is not good enough (at least you and acw told me) and the vci-100 aint have one.

i don't understand why you say is not professional connect the jacks from my Audio Interface to my PA speakers... is there a technical issue?, what i just read here, theres nothing wrong at all.

anyway... what is the advantage to connect my speakers via XLR?

im just in time to change my purchase for another sound card or PW mixer that u guys recommend me. i want to achive the best quality output.
i just despited the NI Audio dj 8 since it just have RCA outputs given my active set up.
 
since i got the vci-100 and my speakers bought... what else buy? in order to prelisten and feed my speakers? some here recommend me the echo audio fire since it has:

FireWire (IEEE 1394a) interface with 8' cable
Bus powered with 6-pin FireWire interface
External 12VDC power supply provided
2 auto-sensing universal inputs (mic/guitar/line):
Meters, trim knobs & 48V phantom power
2 balanced ¼" analog inputs:
112dB (A-weighted) dynamic range
+4dBu / -10dBV nominal levels
4 balanced ¼" analog outputs:
114dB (A-weighted) dynamic range
+4dBu / -10dBV nominal levels
S/PDIF I/O at 24-bit/96kHz
MIDI I/O
Stereo headphone output with volume knob
Sync via S/PDIF
Supports full duplex 6 channel in, 6 channel out operation at 24 bit, 96 kHz sample rate
Heavy-duty aluminum case
Near zero latency hardware monitoring

is it not enogh to connect my speakers an pre listen? do i need a mixer too? why?
 
Ok

Lets try to simplify this a bit.

XLR is the most sturdy and proffesional connection type. And is balanced line.

1/4" TRS is also balanced line but is not quite as sturdy as XLR. This jack looks the same as the one on your headphones.

1/4" single ended mono jack cables are not balanced, have one less wire and one less connection on the jack.

Don't confuse 1/4" mono cables with TRS balanced. TRS balanced cables have the same noise cancelling properties as XLR cables. Both work just as well in this respect but the jack type are more easily damaged.

As has been said before good quality mixers and some of the better sound cards provide balanced line outputs to connect to your choice of active speakers. But you need to check with the manufacturer and make shure before you buy.

I am sorry if this has been getting confusing but I think this is because we have been trying to discuss all the options avalable to you.

Daz

 
since i got the vci-100 and my speakers bought... what else buy? in order to prelisten and feed my speakers? some here recommend me the echo audio fire since it has:

FireWire (IEEE 1394a) interface with 8' cable
Bus powered with 6-pin FireWire interface
External 12VDC power supply provided
2 auto-sensing universal inputs (mic/guitar/line):
Meters, trim knobs & 48V phantom power
2 balanced ¼" analog inputs:
112dB (A-weighted) dynamic range
+4dBu / -10dBV nominal levels
4 balanced ¼" analog outputs:
114dB (A-weighted) dynamic range
+4dBu / -10dBV nominal levels
S/PDIF I/O at 24-bit/96kHz
MIDI I/O
Stereo headphone output with volume knob
Sync via S/PDIF
Supports full duplex 6 channel in, 6 channel out operation at 24 bit, 96 kHz sample rate
Heavy-duty aluminum case
Near zero latency hardware monitoring

is it not enogh to connect my speakers an pre listen? do i need a mixer too? why?
 
i think we are out phase in the posts. jejeje
 
The VCI 100. is a controller which as i'm shure you know will allow you to control the software functions of VDJ up to and including the mixing functions.
Yes a sound card is still required. What we are discussing is how best to get the signal out of the digital world (your computer) and into your active speaker system.

The best solution using a sound card/interface is with XLR balance line outputs (only found on some of the higher quality cards). The next best solution is TRS jack ( more common on sound cards).

Just because you have bought the Vestax already does not make it useless, but based on what you seam to want to do it may not be the most flexible solution.

A good quality sound card/interface driving a mixer which provides XLR balanced outputs to your speakers is the best solution. But not the only one.

You can still use an external mixer with the Vestax as the controller and just not use the mixer part of the Vestax. Perhaps this would be an option for the future.

Daz
 
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