50' speaker or 50' interconnect?

Generally, the answer is 50' interconnects, and balanced interconnects if possible.

However, your results indicate that perhaps only experimentation with both speaker cables and interconnects will provide a satisfactory answer.

Low capacitance interconnects can be purchased or fashioned from Mogami 2534 or Gotham Audio GAC/4-1 microphone cable. I also use Oyaide PA-02 for 30' XLR interconnects with excellent results.

...btw, 50' Mogami 2534 mic cables can be purchased from several retailers including Guitar Center. They can be returned within 30 days for a refund.

If you used cheap 50 foot XLR and did not try a LONG break in you are not getting the results possible.
The minimum quality would be the Mogami (not a copy!!) suggested above. The minimum 'audiophile' 50 ft would run you about $1,000. or so (so I WOULD try the Mogami and use it for at LEAST a month or two)
I use a Kimber Hero 7 meter ($700 plus) XLR (half your distance!)
To get a speaker cable that can go 50 ft is going to cost a LOT more for the same quality.. so stick with the XLR IMO.

Ocos speaker cables are supposed to be good for up to 100 meters.
http://www.dynaudio.com/eng/systems/lines/accessories/ocos.php

I'm using about 35 ft of balanced Anti-Cable interconnects from the preamp to the amp with about 4 feet of speaker cable. Sounds great....no noise, big, wide, deep soundstage, etc.

If you are running balanced interconnects, you need to make sure your equipment is also truly balanced to reap the benefits of balanced. An XLR jack does not mean truly balanced, necessarily

What preamp are you using, and if you can readily determine it, what is its output impedance?

The higher the output impedance, the more critical cable capacitance will become. The symptom of cable capacitance that is too high in relation to output impedance would be upper treble rolloff, and its associated subjective effects (sluggish transients, dull sound, reduced ambience, etc.).

I can do some quick calculations for the Mogami once I know the output impedance of the preamp.

Here is a link at which you can purchase a 2534-based 50 foot length of terminated Mogami Gold Studio xlr cable, for $98.95, from B&H Photo Video (an excellent seller). They have a 15 day return policy:

http://www.bhphotovideo.com/c/product/318716-REG/Mogami_GOLD_STUDIO_50_Gold_Studio_XLR_Male.html#features

Blue Jeans xlr cable, based on Belden 1800F, has a bit under half the capacitance of the Mogami, but does not provide the Mogami's quad conductor configuration which improves noise rejection. Some of the higher end cables, such as some Cardas cables, also have considerably less capacitance than the Mogami's, but of course will be very expensive in that length. So I second the suggestion of Mogami unless the output impedance of your preamp is particularly high at high frequencies.

Regards,
-- Al

Hmm, I would have tended to run the speaker wires longer for fear that longer runs of low level signal wires are more subject to noise and interference from external sources. I guess not so much if shielded.

BTW, I have speakers up to about 15-20 yards or so away as the crow flies connected via standard guage commercial in-wall speaker wire to my system and I do not hear any ill effects compared to the pair sitting just a few feet away and connected via higher end 12' Audioquest cv6 wires, so running longer lengths of speaker wire is not something I fear based on experience.

I would have tended to run the speaker wires longer for fear that longer runs of low level signal wires are more subject to noise and interference from external sources. I guess not so much if shielded.

And especially not so much if balanced! And that applies whether or not the components are "fully" (internally) balanced or not, as long as the balanced driver and receiver stages are well designed.

I have speakers up to about 15-20 yards or so away as the crow flies connected via standard guage commercial in-wall speaker wire to my system and I do not hear any ill effects compared to the pair sitting just a few feet away and connected via higher end 12' Audioquest cv6 wires, so running longer lengths of speaker wire is not something I fear based on experience.

In addition to the cables themselves, speaker impedance (the higher the better), the variations of speaker impedance with frequency (the less variation the better, especially at high frequencies), amplifier damping factor, and the criticality of amplifier damping factor to the particular speaker, are all variables that will significantly affect whether or not very long speaker cables will be acceptable.

Best regards,
-- Al

Al, good points.

Cheers!

I'm running about 30 feet of phoenix gold balanced cable between my phono stage and pre-amp. I'm very happy with it and price was about $75 (if memory serves). If I was dealing with your issue I'd give them a call.

Based on cables alone, the 50' balanced interconnect is superior to the 50' speaker cable. In the case of long cable runs attenuation and noise injection are the big concerns.

Of the two problems, noise is the most problematic for interconnects. The fundamental design of the XLR circuit is based on transmitting two identical but inverted polarity signals on a pair of conductors. At the receiving end, any signal that is not on the opposite polarity conductor is considered noise and is rejected which leaves only the signal originally transmitted through the cable. Active circuits at both ends of the signal path (cable) helps alleviate the attenuation issue.

Noise is not a significant issue with speaker cable because of signal strength. It's really hard to inject enough noise on a speaker cable to create noise on the speaker end. However, attenuation can have a very noticeable affect on the quality of sound from the speaker. As the signal is affected by the attenuation (capacitance, inductance, resistance) of the conductor, the sound from the speaker is changed. Your mileage may vary on the degree of the change but speaker cables beyond 8 to 12 feet will increasingly influence the sound coming from your speakers.

Obviously it is more complicated than that but, without knowing any thing else about your system and environment, the cable question is pretty straight forward.