Recommendation for an audiophile speaker cord that is not "bright"?

A friend has loaned me the Nordost Valhalla I and II as well as Nordost Frey 2 cables. They are wonderful speaker cables but do emphasize the "brightness" of my system including my Wilson audio Sahsa 2 speakers.

Any suggestions? Would used Transparent cables provide a richer bottom end? What about Audience Reference?

Any recommendations would be greatly appreciated. - Thank you - Gerry
Hmm.  I believe Nordost has the rep of tending to be forward or bright.  Silver plated conductors, of that which Nordost leans heavily, can be "bright".  I'd suggest cables that do not have silver content, such as Wireworld Eclipse 8.  They are a 9 gauge cable, however, but with speakers like the Sashas you probably have a pretty stout amp.

Staying in the solid copper conductor design, Audioquest also makes some great options, but frankly they get pretty expensive.   
Give Wilson a call and see what they recommend. They do a lot of shows every year, not sure who they partner with. Off the top of my head I would try Acoustic Zen Hologram, Kubala  Sosna and Kimber cable.
If you like the cables in general but find the brightness an issue, you might try different plugs.  The top of line IEGO 8095 is rhodium over silver and this plug has had a smoothing effect in my system.  My speakers use Eton metal dome mids/tweeters and can have more bite than I like.  My power cords are DIY solid core copper with silver plate.  I usually use Oyaide 004 plugs but have added the IEGO's to a couple cords and the detail is still there and the highs are at least as open and transparent but somehow smoother without the bite.  Something to consider.
Anticables, really tough to beat
then if ya want to spend a bit more money an Audioquest with DBS, stock to copper

have fun, enjoy the music and the search 
Look into WyWires. All copper... no silver or silver plated. I used to be a big fan of silver cables but as my humble system has become more refined I’ve gone back to copper. WyWires have great balance and don’t draw attention to anything; they just get out of the way. Only listened to the Sasha’s with a Gryphon Diablo 300 in a store, but it was very revealing and I would have preferred a little more warmth. Not sure what model but they were running but they were using Transparent Cables. Sound was too hot for me but was very dynamic but not fatiguing but still too hot for my taste. Source was an Aurender N100 I believe. Not knowing the rest of your system or your room it’s hard to know if it’s the Nordost or not but my experience with other Wilson speakers is they are very revealing and I feel they require more system matching than other speakers. I use a mix of Nordost as well but not the upper level stuff but I do find they blend well with WyWires. You’re just going to have to experiment and find what’s right for you. What is the rest of your cable loom and what speaker cables do you personally own? You mentioned the Nordost are a friends. Upper level Cardas might be another line to look into. 
Kimber 8TC should do the job for you.

Anticables were mentioned. I tried them and found them bright; and others have, too, so I'd proceed with caution.
Consult with The Cable Co and have them send you options to audition firsthand (if you are in the U.S.).
The Acoustic Zen mentioned before are an excellent choice for your issue and I have used them with my Wilson's for 8 years with great effect. You might also consider an older pair of the PS Audio Xstreem Statement cables for even more taming of the shrillness. Enjoy the music.
Thank you, everyone, for your responses. I do live in the U.S., and the following recommendations were made to me by Wilson Audio and the Cable Company:
1. Wilson recommends Transparent speaker cables;
2. Peter at the Cable Company (a great fellow!) recommended either Cardas Clear or Clear Beyond or Audience Research.
If you don't mind being anti-audiophile, I've tried the very reasonable speaker cables sold by Blue Jeans Cable and found them pretty uncolored. Technically (in terms of resistance, inductance, and capacitance), the Belden wire they use for them is among the very best.
Since the others are much more expensive, I am going to try the Acoustic Zen first. Thanks!

Audience AU24SX. Don't do anything wrong; clear, natural and balanced. Can't go wrong, and reasonably priced.
I would seriously consider Tomic601’s recommendation.
I owned a set of Transparent cables, and found them rather dull-sound wise, and they cost a small fortune. One that was not recouped when selling them.
Yeah, the Wireworld Eclipse 8 would be a solution, but they are around $1500, not sure what the OP's budget was.

I assumed if the OP has tried and considered Nordost Frey 2 that Wireworld Eclipse 8 wasn't over his budget.
Wireworld is usually the opposite of bright, but with good imaging as a trade off. May be ideal for you.
The Cerious Technologies Graphene Extreme cables are very good sounding and don't here toward brightness.  Their Matrix cables are much better, but cost almost 3 times as much.  I have the CTGE cables which tended to tone my VMPS RM40 speakers with 40" of ribbons per speaker down and give them more of an organic sound with better balance.  They go for $640 for an 8 ft. pair, but you could find them used for around $350-400 a pair.

Post removed 
I will second the suggestion for Cardas.  If you can find a used pair of Cardas Golden Reference, they are excellent and not bright.   Expensive at the time, but can get a better deal, now. are demoing some $2000-4000 per meter pieces of wire and you want other peoples advice what is better? OK, I will be like the rest. Why are you bottom feeding with the cheap stuff? Spend more (like I did) and it will sound much better.

Being more serious............It is all about synergy. At the prices you are contemplating there is a better than 50% chance you could find something better for your system at much lest than half the cost (maybe even 1/10th). What cables have you tried so far that sounded OK on your system? How much did they cost? And what are you hoping to improve by upgrading?
I would also agree with those that recommended the Cardas Clear Reflection. I auditioned them against some speaker cables that I thought for sure would blow them away, but they ended up bettering them.  Not overly warm, and not bright at all, for my system they were just right.
Seriously? (Eye roll) send me your cables and $1000 and ill soak them in my patented anti-bright cable conditioner for one full cycle of the moon and send them back...
Analysis plus crystal ovals might work well for you.  I liked them so much in my somewhat bright/forward system that I ended up purchasing a full loom of their interconnects as well.

they are fairly reasonable price-wise when purchased new, but you can find really good deals in the used market.
I have what used to referred to as some of Wilson's least forgiving speakers (W/P 5.1).  I splurged when I found a deal on some used MIT Matrix HD 60 bi-wire cables (for around $1500 IIRC). And they are a match made in heaven with the Wilsons. Some folks object to the retail MIT pricing, but they really are like a component upgrade that makes everything come together beautifully. Wilson and Magico used to use MIT (may still) in  their audio show demos. 
Morrow Cable, not bright but very accurate and not very pricey. They are made of woven Litz wire OFC copper. The improvement I heard over silver plated OFC copper was like night and day! They run 50% off specials for Agon members and trade ins. You may be able to talk Scott into extending that to you. They will make and burn in your cables in about two-four weeks. Nothing is stocked, everything is custom terminated to your specs from a wide variety of termination selections.
Not helpful perhaps but Wilsons can sound bright if your ears are sensitive to those frequencies (mine are and I can’t tolerate Wilsons). I do not think speaker cable can overcome this. 
Triode Audio labs they are consistant at many shows .I personally have owned top name cables at several times there cost 
and here are as good and better in most cases .
and I own there American series digital and high power cords $5-700 they are a true bargain using only top Copper connectors not cheap gold over brass like most. To enhance and protect your 
connectors stabilant -22 is great including vacuum tube pins 
first clean all connectors with pure isopropyl alcohol .
for AC connectors Furutech nano fluid,it  is excellent but takes 2-3 weeks to dry but for sure enhances detail . Just a tip .
Elsdon Wonfor audio LS25.  These are a proprietary alloy  they are utterly transparent with no phase distortions. If you have a well balanced high end system that you like,  these will give you what you have in spades. Pinpoint stereo imaging , WIDE soundstage true speaker response.

The designer was responsible for tellerium Q cable designs but parted company and took forward some of their design principles.  
As the OP, just saying that I loved the sound of my system before I tried the Nordost Frey 2, Valhalla 1 or Valhalla 2 speaker cables.

I have Nordost Valhalla power cords, Nordost QBase and a dedicated main and ground, and a Nordost QPoint under my preamplifier. These were tremendous, incremental upgrades that really "lowered the noise floor." 

So, I love my Wilson speakers and the rest of my system.
I realize I will probably get a lot of heat for saying this but it’s Christmas time so what the hell. The primary reasons cables sound bright can be placed right at the doorsteps of (1) they aren’t broken in yet, (2) they’re in the wrong direction and (3) it’s something else in the system that’s producing bright sound.
I would suggest Kimber Kable Ascent Series 8TC or 12TC cables . I believe the 12TC would work best with your Wilsons. 
(  I understand that their Summit Series Monocle XL is also excellent ) .  
geoffkait- My system is great - it now consists of an Esoteric K1X (bought it in Japan this fall), Shunyata OCXO OP19 master clock, McIntosh preamp, ARC GS150, etc. It sounds great with my run-of-the-mill copper speaker cables. And the Nordost cables I tried were broken in and in the right orientation. I know a bit about the last detail from my experience in the OR. 
Mine is a second vote for Analysis Plus.  I found no need to go to the expensive end of their line either, their Oval 9's are not colored or bright, just transparent.  Like they are not there!
My system is great!

>>>>>That’s what everyone says. Think how much better your system would be with some high end speaker cables. Ironically Nordost actually doesn’t believe in directionality. They think cables break in correctly no matter which way you orient them. Can you believe it? I guess Nordost never got the memo. 😛

Note to self: They were right! It is like shooting fish in a barrel. 🐠🐟🐠
I bought 2 pairs of Nordost interconnects.  I wanted to put them between the preamp and amp. The first were Nordost Red Dawn and the second we’re the Nordost Leif series.  Both cables were used but burned in for 72 hours on a Kharma cable cooker. I ran them in for another 2 weeks and they were way too bright for my taste. 

I kept the cables but used one in each system for my tuners where a little extra energy was ok. At the suggestion of a member of the Cable Asylum, I contacted Chris at VH Audio and told him my equipment and what I was looking for sound wise. He constructed me a gorgeous pair of 1.5 meter cables for $399.00 and burnt them in on his cable cooker.  As soon as I put them in my system, I knew they were what I was after.  I like them so much I will be ordering a couple of more pairs after he gets back from CES in January.  

I cant say enough good things about Chris.  He listened to me and used his vast knowledge of cables and connectors to give me exactly what I was looking for.  I ordered them on a Thursday and on the Friday, he had built them and was burning them in.  The shipped out the following Monday( free shipping) and I received them on Thursday. Exactly a week from start to finish for a custom order.  That is simply amazing. To the OP you should check with Chris at VH Audio, he will not sell you something just to make a sale. He will steer you right and most likely save you money as well. 
Okay, let me get this straight.  So there's no consensus in a cable thread?! 

213runnin I think most everyone is saying spend some more money and get some  more cables. 
And that does not a consensus make.  I feel like you're going to insist that it does, so...

Wildly different price points, wildly different design types and brands and... my post was merely a light hearted observation.
This is a seriously disappointing thread. Lots of great and likely somewhat useless wiring suggestions. If you find your speakers "bright", wire is not where you start making changes .... ask why do your speakers sound bright?

- Are you running tube gear or solid-state? If tube gear, the damping factor may be low in the base, especially around 100Hz where these speakers dip to 2 ohms. That could be rolling off the bass making you think the highs are bright.

- More likely is you have an inadequately treated your room for these speakers. Room response makes a speaker bright, not the speaker on its own. Some additional absorption, a carpet, ceiling diffuser/absorber, etc. may be ideal and give you better overall imaging.
I would absolutely try Morrow Audio cables.  They have a very good return policy.  I started with the level 4 interconnects and paid for the burn in.  I had been auditioning several cables through the Cable Co. (highly recommended) and I decided to try the Morrow M4’s on sale through Morrow with a no questions asked return policy.  I was amazed.  A smooth, glare free transparency, while still conveying the emotional content of the music.  Incredible dynamics and balance across bass, midrange and treble.  I was so impressed I returned the M4 interconnects and upgraded my entire system to level 6 interconnects and speaker cables.  At 200 hours these really bloomed and continued to get better, significantly better, through 600 hours!  I’m just saying, I have found these Morrow Audio cables to be nothing short of miraculous.