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Discussion Starter · #1 ·
Is there any advantage to using a XLR-RCA cable rather than just useing a regular RCA-RCA cable to hook up a sub?


The sub I am looking at has an XLR connection, however my reciever only has a RCA out.
 

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Unless the receiver/pre-pro had an XLR output. Then it would be balanced from end-to-end.


In other words... converting XLR to RCA provides no benefit(s) since RCA is inherently unbalanced.
 

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Quote:
Originally Posted by Harrypt /forum/post/16922606


Not no benefit, it is a detriment. XLR is +4dbv, unbal is -10dbv. If you mix them you will either over or under drive your signal.

A balanced signal only produces +4dB when the entire differential signal is used. Since this is unbalanced (mentioned many times) the resulting signal level is 6dB lower.

You can't over or under drive a signal, BTW.
 

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Quote:
Originally Posted by Ratman /forum/post/16921052


Unless the receiver/pre-pro had an XLR output. Then it would be balanced from end-to-end.

I think you mean to say that there would be no advantage unless the sub had XLR inputs(s).

Quote:
In other words... converting XLR to RCA provides no benefit(s) since RCA is inherently unbalanced.

Agreed. An unbalanced input pretty well limits your options.


The point about +4 versus -10 is relevant, as the more you can attenuate at the load, generally the better. However, many active subs seem to be overly sensitive.
 

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Quote:
Originally Posted by arnyk /forum/post/16925189


I think you mean to say that there would be no advantage unless the sub had XLR inputs(s).

No I didn't.


I think you meant to read the 1st post more carefully.

Quote:
Originally Posted by 2fastman /forum/post/0


The sub I am looking at has an XLR connection, however my reciever only has a RCA out.
 

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Quote:
Originally Posted by Harrypt /forum/post/16922606


Not no benefit, it is a detriment. XLR is +4dbv, unbal is -10dbv. If you mix them you will either over or under drive your signal.

I agree it is of no benefit with regard to balanced/unbalanced, but the part about the levels (+4dBu and -10dBv, btw) is horse puckey, IMO, when dealing with preamp>amp connections.


If you were talking fixed level inputs and outputs I might agree.
 

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Quote:
Originally Posted by 2fastman /forum/post/16920335


Is there any advantage to using a XLR-RCA cable rather than just useing a regular RCA-RCA cable to hook up a sub?


The sub I am looking at has an XLR connection, however my reciever only has a RCA out.

The better part of the benefits of balanced connections accrue on the input side. Therefore, a properly-constructed cable running from an RCA out to an XLR input can provide an audible advantage over an improperly constructed one that would not take advantage of the benefits of an XLR input.
 

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Quote:
Therefore, a properly-constructed cable running from an RCA out to an XLR input can provide an audible advantage over an improperly constructed one that would not take advantage of the benefits of an XLR input.

Feeding a balanced input with an unbalanced output results in an unbalanced interconnect, with no advantages of a balanced interconnect. You cannot make a differential interconnect simply by using an XLR on one end.
 

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Quote:
Originally Posted by 2fastman /forum/post/16920335


Is there any advantage to using a XLR-RCA cable rather than just useing a regular RCA-RCA cable to hook up a sub?


The sub I am looking at has an XLR connection, however my reciever only has a RCA out.

Does your sub have RCA input also?


If it does use it because there are several issues with any RCA to XLR connectionsa and over all there is no benefits of using XLR vs RCA unless you have high powered systems, long runs and lots of EMF stuff all around....XLR balanced cables are better in that environment.
 

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Quote:
Originally Posted by duvetyne /forum/post/16934169


Feeding a balanced input with an unbalanced output results in an unbalanced interconnect, with no advantages of a balanced interconnect. You cannot make a differential interconnect simply by using an XLR on one end.


The *right* way to construct a RCA -> XLR incterconnect is shown at http://www.rane.com/note110.html , diagram 17.


The advantage of this method over a unbalanced hookup is that the load senses the difference between signal and ground at the source, rather than sensing the difference between signal and ground at the load. There is often a slight voltage difference between ground at the source and ground at the load.


I've used this method many times and at times it does give a reduction in hum. In other cases it has no benefits. Since it involves no extra cable, its cost is essentially zero.
 

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Quote:
Originally Posted by 2fastman /forum/post/16920335


Is there any advantage to using a XLR-RCA cable rather than just useing a regular RCA-RCA cable to hook up a sub?


The sub I am looking at has an XLR connection, however my reciever only has a RCA out.

Since the sub uses +4dBu balanced inputs then you may get a better signal to noise ratio from the sub by converting the signal from the preamp (-10dBV single ended) to to +4dBu. This requires an inline amplifier/buffer circuit.


You don't HAVE to do this though if you can put up with more noise (usually not very much but it is case dependent) and can just run the center (signal) pin on the RCA to pin 2 (plus) on the XLR and the shell (ground) of the RCA to pin 3 (minus) on the XLR. Because doing it this way runs the RCA straight to the XLR without a boost, the sub may end up playing too quiet and you'd have to bump up the gain higher than normal with the sub to blend it properly.
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by penngray /forum/post/16934372


Does your sub have RCA input also?


If it does use it because there are several issues with any RCA to XLR connectionsa and over all there is no benefits of using XLR vs RCA unless you have high powered systems, long runs and lots of EMF stuff all around....XLR balanced cables are better in that environment.

Yes my sub has both RCA as well as XLR

My AVR only has an RCA


There will be electrical in the area of the sub as it is a powered sub and I have put the receptical near the sub location, thus eliminating a long powercord.

its is 110Volt so I am not sure if this will disrupt the signal or not seeing as the cable is sheilded
 

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Quote:
Originally Posted by 2fastman /forum/post/16941312


Yes my sub has both RCA as well as XLR

My AVR only has an RCA


There will be electrical in the area of the sub as it is a powered sub and I have put the receptical near the sub location, thus eliminating a long powercord.

its is 110Volt so I am not sure if this will disrupt the signal or not seeing as the cable is sheilded

The more likely problem is known as "ground potential difference". If you work your way around your house with lights and equipment turned on, using a voltmeter you may measure a voltage difference of up to a few volts beween the safety ground pins on different outlets. Being on different circuits can make this problem more likely. With unbalanced inputs, this can be an insurmountable problem.
 

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OK from the professional audio systems installer's data bank. The RCA toXLR adapter cable is limited by the weakest lik in performance: the RCA. There is zero audio improvement of mixing XLR and RCA. The XLR depends on a balanced output with reference to ground and an input that is identical. In a balanced system, the ground serves no purpose except as a hum/ noise shield connection. It is NOT part of the audio path.


In an unbalanced system RCA or 2 conductor 1/4 phone, The shield IS tied to ground as a return path for the audio signal. In a balanced system. if either end of the cable (pre out or amp in is connected to 2 conductor plug of any kind, that effectively unbalances the entire system. There is zero change in audio quality from (improvement or degradation) from doing this as long as the cable is a decent quality and not longer than 30 ft.


The standing industry rule for unbalanced cables is 30 ft maximum. Past that, the single ended cable is more prone to induced noise or interference, even radio reception,. That was the whole purpose for the development of balanced systems in the first place.


Professional systems NEVER use the flat chassis ground solder lug on an XLR either and many systems have pin 1 (audio ground) connected to the chassis ground through a 51 ohm resistor in series with a .1 mfd disc capacitor. This is to complete a shield-to-electrical-ground connection sufficient for shielding but able to isolate the electrical ground. The reason for this is safety.


A person in contact with a microphone or electric guitar can be electrocuted by a ground path to another piece of equipment. The capacitor isolates the audio ground from the electrical ground. It has happened many times.


Professional balanced systems usually do not connect the pin 1 shield on ONE end of the cable (from the balanced output) of an audio device as it is not necessary and grounds from 2 points can cause hum.


On the home audio systems, just tie pins 1 and 3 together as the shield and pin 2 goes to the center pin on the RCA. simple and functional. Not ideal, but it will work.


Most equipment with the option of XLR or RCA connections is designed to provide the same gain in the first stage so audibly there is no difference. The adavantage is that truly balanced XLR interconnects (both inputs and outputs)can handle longer runs and the connectors lock in place.


Audibly there is no advantage.
 

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Why do people like to confuse new people to the hobby?


How about just telling him that if both the sub and the AVR has RCA connections then he should use a RCA to RCA cable.


Its nice to post extremely detailed info for some to learn but the OP simply just needs to know there is no SQ difference and he should use RCA to RCA cables.
 
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