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Bi-wiring Bi Amp`ing Monitor Audio RS8 Nad C352

post #1 of 26
Thread Starter 

Hi there, does any one know how to bi-wire in right way? How to bi-wire, horizontally or vertical?

I do have TWO nad c352 amp`s with built-in pre-amps. And Monitor audio RS8 speakers.

Is it worth bi-amp`ing?

Any advice is welcome. 

Thanks.

post #2 of 26

I wouldn't bet on bi-wiring helping given those aren't exactly current-hungry Dynaudio towers (and even Dyns don't have bi-wire terminals), but if you really just want to try, use one amp for the mids, then hook up a cable to its Tape/Rec loop out going into the inputs on the other amp, then hook up that one to the tweeters. In this set up you have a independent gain control for the tweeters, so you can set them lower or higher relative to the mids. Problem here is every time you move the mids' volume, you have to adjust the tweeters' too.

 

You can get a passive preamp though, that way when you match the gain on both, so you have a master preamp to control the system volume. This is essentially how car systems with active crossovers (ie, crossover is applied before the amplifier) are set up, with the gain on the tweeter and midwoofer matched to each other as well as to the distortion levels relative to the receiver's or processor's preamp output.

post #3 of 26
Thread Starter 

Thanks PortegeManiac, Hmmm.

At the back of the speakers, where is 4 connections. Ready for be-wire. I thought first 2 are for mid`s and high`s(1 tweet + 1 mid), and others (x2 bass drivers) one is for bass only? And yes, i bought second NAD just to try, see the difference. If i like it, i will keep, not  i just re-sell to my friend.

BTW forgot to mention i will drive them from PC sound card ONLY. Do have Cambridge audio DacMagic Plus, but will send it back to shop. Not a big impression.


Edited by Artcheezzz - 3/12/13 at 6:35am
post #4 of 26
Quote:
Originally Posted by Artcheezzz View Post

At the back of the speakers, where is 4 connections. Ready for be-wire. I thought first 2 are for mid`s and high`s(1 tweet + 1 mid), and others (x2 bass drivers) one is for bass only? And yes, i bought second NAD just to try, see the difference. If i like it, i will keep, not  i just re-sell to my friend.

 

Depending on how the crossover is set up, but just looking at the drivers that's the most likely config. What we don't know exactly is whether it's a 2.5-way crossover (obviously another high/lowpass between the tweeter and midrange, but the bass drivers play the same freqs), or it could be a 2.5+0.5-way crossover (another high/low pass between the two bass drivers, essentially making one dedicated for the really low bass). Either way, having one amplifier on the midrange+tweeter and another for the bass drivers will be best.

 

I just realized there's a way to do vertical bi-amping on this while still maintaining some control over bass and midrange/treble gain, while having the benefit of only one channel on each amp driving the more demanding bass woofers. Put one amp near each speaker, then have the main interconnect cable go into one channel input on each amp. Then from the tape outs of each channel, run another interconnect into the input to the other channel. Then use L/R balance control to bias the gain for the bass woofers or midrange-tweeter.

 

Source >> Left Amp Left channel Input >> Tape Out Left Channel >> Amp Right Channel Input >> Right Channel speaker out into midrange/tweeter, Left channel speaker out into bass woofers

           >> Right Amp Left channel Input >> Tape Out Left Channel >> Amp Right Channel Input >> Right Channel speaker out into midrange/tweeter, Left channel speaker out into bass woofers

 

                      

 

Quote:
Originally Posted by Artcheezzz View Post

BTW forgot to mention i will drive them from PC sound card ONLY. Do have Cambridge audio DacMagic Plus, but will send it back to shop. Not a big impression.

 

Personally the DACMagic will most likely give a better improvement than bi-amping. For one, I had the 304 before (35wpc), and whenever there was a situation with local audio/HT-philes going to test HT gear, I bring the NAD304 with us just so they can compare just how much most of the lower model receivers suck with driving multi-driver speakers on two channel audio (the receivers' bass playing Dream Theater was usually more like a mudslide than double-pedal work; I only liked one when a sealed 8" sub was used), or how much the manufacturers are lying through their teeth with the specs. Also when people use one amplifier channel on each individual driver in a serious car audio set-up, the real reason for that is for active processing - that includes individual time alignment* and gain control. Now, that's usually easier in a car because not only would you have gain controls at least for every channel pair in an amp, but receivers or separate processors that do this also have a level control for the tweeter output**. So for example in my car I have four RCA cables carrying time-aligned and frequency range-specific signals, but the tweeter signals are already set at -4db on the receiver, then the amp's two channels for the tweeters with 75wpc are set to just off minimum gain on the amp, while the 150wpc pair for the midwoofers are set to the third dot on the knob.

 

Those NADs may have such markings on the knobs, but remember that the initial problem is that there isn't an active crossover splitting the signal - all line level signals are fullrange until they enter the passive crossovers on the amps. I don't discount the benefit of driving double bass drivers with a separate channel, but then again there's still the probability that having one extra interconnect carrying the signal to the other amp channel (or even a Y-cable) might actually introduce added impedance or something to that effect. In any case, since you already have the amp anyway, try this out, but before ultimately deciding it makes no positive difference, at least wait to try it with the DACMagic too.

 

 

 

*kind of like what higher model HT receivers do, except instead of LCR-Surr-Sub, it's L tweeter-R tweeter-L midrange-R midrange-L midwoofer-R midwoofer-subwoofer that will be set- up so sitting off to one side of the car won't mean that you'll hear the closer side first

**since the crossover is applied at the digital level, the receiver knows what signal goes to what driver


Edited by ProtegeManiac - 3/12/13 at 9:05am
post #5 of 26

Biwiring involves using two pairs of speaker cables from one amp. Ideally they should all be the same length and type. For the NAD, you only have one set of binding posts - red/black (L) and red/black (R). First, remove the jumper plates from the back of your speaker binding posts. Connect one pair of speaker cables to each set of binding posts (two cables connected to L set and two cables connected to R set). Then connect one cable from L (amp) to L (tweeter) on your speaker. Do the same for the woofer section. Repeat for the right speaker. Now you should have a pair of speaker cables attached to each speaker from one amp. Since you've separated the tweeter and woofer signals into separate cables, there's less chance for the woofer (bass) frequencies to modulate the tweeter (midrange and treble) frequencies, or so the theory goes.

 

Looks like the NAD amp can only do horizontal biamping. This means that one amp will be driving the tweeters and the other will be driving the woofers. It might be hard to control the volume output this way - you'll have to make one amp do double duty as the preamp unless your source has a volume control. If the source doesn't have a volume control, then remove the pre-out / main-in jumpers on one amp - this will function as a power amp only. Then connect your source to a line-level input of the jumpered amp. Take another pair of interconnects and connect PRE-OUT2 to MAIN-IN of the jumperless amp. Then hook up your woofer sections to one amp and your tweeter sections to the other.

 

I can't picture a vertically biamped configuration with only two integrated amps that won't involve setting the volume level separately between left and right channels - a less than ideal situation.


Edited by yage - 3/12/13 at 10:27am
post #6 of 26
Thread Starter 

Wow, that`s even more than i expected. :) 

Thanks PortegeManiac. Clearly can see you are professional in car pro audio and not just. :) Thanks for your advice and detailed explanation. (wouldn`t even image this possibility of amp`ing, interesting idea with balance option)

I will try DacMagic plus again, because i was connected with (very bad) RCA cables, because failed to buy right XLR to RCA cable :) It sound better for sure, but not for £350 i think :) Because i don`t need many features what can provide the PLUS (upsampling, bluetooth, extra inputs and so on...), i think older DacMagic will do job what i need, reduce background noise and add more clarity.

But background noise is not that terrible as you would imagine, because IF i make MAX volume on PC and 25-30% of volume on amplifier its = just about max volume what you would listen speakers/headphones. SO playing with volume controls I reduce 75% of noise.

I know people saying u should make 25% on PC and 100% on amp to max out your quality. But its just too much noise in this way.

I have feeling i`m doing wrong, please advice here too.

P.S. i do have an old`ish Alphine CDA -105ri and thinking what sound processor, speakers + (built-in woofer) and amp`s i will need in my 2004 C220 merc. But i will make separate threat.

 

 

However, i think Yage option is a better choice in this case. BUT i promise to try both ways :) (Thanks Yage for replay)

My source is PC right now, so would be the best and simplest way to connect PC with both amp`s would be Y splitter and x2  3.5mm to RCA cables? Would that affect any quality?

I can control volume from PC. So can leave all pre-out jumpers in their place?  

And in this case i will be able control mid and tweet drivers with pre-out (bass and treble) and same with bass drivers? is that good idea at all? LOL Or I just do what you told and dont ask stupid questions? :)

Shall I leave "soft clipping" ON to prevent damage of my tweeters?

 

 Sorry For My Bad English

 

SOME PICTURES TO MAKE EASIER TO IMAGINE: 

 

Here is my setup now:

 

 

 

 

Is it good enough these cables?

 

 

Monitor Audio RS8 connections:

 

Nad c352 amp

 

 

Thank you guys, try to test it tomorrow morning. 

Really appreciate


Edited by Artcheezzz - 3/12/13 at 7:41pm
post #7 of 26
Quote:
Originally Posted by Artcheezzz View Post

Wow, that`s even more than i expected. :) 

Thanks PortegeManiac. Clearly can see you are professional in car pro audio.

 

 

P.S. i do have an old`ish Alphine CDA -105ri and thinking what sound processor, speakers + (built-in woofer) and amp`s i will need in my 2004 C220 merc. But i will make separate thread.

 

Not really, I never really competed - but that's more from lack of funds as well as time. I hang out with car audio guys a bit more than home audio guys (although many of us are all kinds of audio geeks, including instruments) because home audio guys here tend to be older, plus their set-ups are at somebody's house (wouldn't want two dozen people driving their wives crazy - walking all over the rug, beer, grilled meat and deep-fried pork rinds everywhere, etc). With the car audio people we just meet at a coffee shop or grill bar with enough parking space.

 

 

 

Quote:

Is it good enough these cables?

 

 

Monitor Audio RS8 connections:

 

Nad c352 amp

 

 

Thank you guys, try to test it tomorrow morning. 

Really appreciate

 

Yes those cables are good enough, but your initial interconnect will be the weak spot at this point, so as much as I would normally say it's better to just get a more powerful amp with more current, I'd say at the very least try this with a decent source that puts out 2v through two RCA sockets. Just follow the diagram I put up there.

BTW when a local warehouse liquidated their NAD304s for about $80 each NOS (NAD factory used to be here in the Philippines but our Communists rallying for labor rights drove business to a Communist country where laborers have almost zero rights, let alone to protest, for the ultimate in socio-political irony) I also picked up a second pair, and before using it for a second system in our house (I lived in a 9-story condo/dorm at the time, college) I tried my Wharfedale 8.4s vertically bi-amped. I liked how I could reduce the tweeter level a bit so the midrange and woofer can be a bit louder, but not having a single master volume was a pain the arse for such a marginal gain. Sold the 8.4's for a pair of Pacific Evos with the swivel-mount tweets so I can give them a bit more toe-in, and that did a lot more to improve the sound. Not only did the Pi10s have more upper-bass impact than the Diamond 8.4s, but the toe-in on the tweets made the soundstage more realistic since it reduced the reflections and the cymbals are more easily heard coming from nearer the center as opposed to the extreme L and R of the soundstage.

post #8 of 26
Quote:
Originally Posted by Artcheezzz View Post

My source is PC right now, so would be the best and simplest way to connect PC with both amp`s would be Y splitter and x2  3.5mm to RCA cables? Would that affect any quality?

I can control volume from PC. So can leave all pre-out jumpers in their place?  

And in this case i will be able control mid and tweet drivers with pre-out (bass and treble) and same with bass drivers? is that good idea at all? LOL Or I just do what you told and dont ask stupid questions? :)

Shall I leave "soft clipping" ON to prevent damage of my tweeters?

 

Typically volume control on a sound card just throws away bits from the audio stream, which reduces your resolution and signal to noise ratio, so I would leave your PC volume at 100% and control the signal volume from the amp. If you do split the signal and use the volume control from your PC, then remove the jumpers from both amps and connect your RCA cables to the MAIN-IN of both amps - this setup also applies to the DacMagic Plus since it can function as a preamp.

post #9 of 26
Thread Starter 

Yes those cables are good enough, but your initial interconnect will be the weak spot at this point, so as much as I would normally say it's better to just get a more powerful amp with more current, I'd say at the very least try this with a decent source that puts out 2v through two RCA sockets. Just follow the diagram I put up there.

What you mean 2v? volts? :D What`s source would have 2v? I use Asus Xonar d2x and read here:

http://sound-cards-review.toptenreviews.com/asus-xonar-d2x-review.html

The D2X is quite impressive when it comes to overall performance. Signal-to-noise ratios (SNRs) give us a ballpark figure of how quality the sound is and both the output and input SNRs are around 118 dB which is quite impressive. There is just a pinch more harmonic distortion compared to the HT Omega's Claro Plus+ but since it's only 0.0001%, it's safe to say that you probably can't tell the difference. Both sound cards have 2 voltage regulator modules to keep the power flow in check where it's supposed to be.

So would that be enough for Y Splitting?

 

And i`m VERY happy how they sound from one NAD amp (was bi-wired with 1 amp since i bought). It was more than enough power. Just thought, speakers can handle 40-175watts 6ohms, (and my amp is 80watts 8ohm = 120watts 6ohms) no?  So wonder how speakers would sound with max power + i will have extra power if i need it in future. 

I`m OLD thinking, and i believe that older bigger amp`s are better than new smaller at same price point. So i will stick with old stuff now :)

Plus i do like a lot NAD c352 headphone 220ohm output. As far i know newer models (NAD) does not have that powerful headphone out.


Edited by Artcheezzz - 3/12/13 at 8:48pm
post #10 of 26
Thread Starter 

Thanks for quick replay. One more annoying question

I like to listen default, plain music, and i need adjust ONLY treble and bass when i swap headphones (HD650 need more bass<>ah-d600 need more treble) 

Its quicker to adjust on amp, so can i leave both pre-outs and "play" with them VERY carefully?

post #11 of 26
Quote:
Originally Posted by Artcheezzz View Post

What you mean 2v? volts? :D What`s source would have 2v? I use Asus Xonar d2x and read here:

http://sound-cards-review.toptenreviews.com/asus-xonar-d2x-review.html

The D2X is quite impressive when it comes to overall performance. Signal-to-noise ratios (SNRs) give us a ballpark figure of how quality the sound is and both the output and input SNRs are around 118 dB which is quite impressive. There is just a pinch more harmonic distortion compared to the HT Omega's Claro Plus+ but since it's only 0.0001%, it's safe to say that you probably can't tell the difference. Both sound cards have 2 voltage regulator modules to keep the power flow in check where it's supposed to be.

So would that be enough for Y Splitting?

 

2v = Sony Redbook (CD Audio) standard output. By comparison for example an iPod puts out around 1.2v through its lineout; HRT DACs make 2.25v. Take note not all CD/PCM sources are rated at 2v, or output at that fixed voltage. Some Denons are at 1.8v, but I can't remember if they're actually just at a fixed 1.8v or they just state 1.8v and the lower distortion % at that level but still actually make 2v (note : even if it's the latter it's not like they were covering up for a really distorted signal at 2v).

 

I suppose the soundcard is making 2v, but the other problem is the volume control. I'm not really into computer audio beyond using one as a digital transport, or now, using them with IEMs,* but depending on the implementation of the volume control you might be restricting the bits on the recording. If however the souncard has a volume control separate from Windows', then I'd hazard a guess it probably works on a hardware level (even with digital controls).

 

 

*Realtek has really improved - my 2008 Vaio was several miles better driving IEMs than my 2004 Compaq, but now my current Acer Aspire sounds like an iPod Touch next to the old Vaio that's more like one of those pre-smartphone music phones; same goes for a few Ultrabooks I've tried (most likely they have the same chip)

 

Quote:
Originally Posted by Artcheezzz View Post

And i`m VERY happy how they sound from one NAD amp (was bi-wired with 1 amp since i bought). It was more than enough power. Just thought, speakers can handle 40-175watts 6ohms, (and my amp is 80watts 8ohm = 120watts 6ohms) no?  So wonder how speakers would sound with max power + i will have extra power if i need it in future.

 

If you're happy with one amp, chances are adding another might not make any more improvements. But still, you already have the amp, so by all means try it.

 

Quote:
Originally Posted by Artcheezzz View Post

I`m OLD thinking, and i believe that older bigger amp`s are better than new smaller at same price point. So i will stick with old stuff now :)

 

That depends. It was more true with older discrete Class A, or even Class A/B, standard size amplifiers compared to the later chip amps,* or even discrete amps, that made too many compromises for size and heat management. By now however technology has developed well enough, Class D or even A/B.

 

One of the more obvious transitions from "old school" to "too many trade-offs new stuff" was in car audio. Back in the late 90s American "iron" really ruled - if it wasn't a Soundstream 12wpc Class A, it's an RF or MTX with a lot of Class A bias despite being actually A/B. The Soundstreams got really hot, but the RFs really got a rep for heat inefficiency because of the heatsink design that made them look like a teflon grill, so over here in the Philippines we called these older RFs "BBQ Grills" and the running joke was that you can fry an egg on it. I listened to a set-up in a (non-US/UK) Ford SUV with A/C vents for the third row seats, and he creatively positioned the amp where the A/C can cool them. If you put your hand near the vent it was ice cold; touch the amps and they're still well above lukewarm. So was the sound - guitars and percussion had a lot of body on these "old school" amps compared to the newer, entry-level amps (like MTXs Road Thunder or Alpine's MRP). Unfortunately with American brands competing for mass production and price, the European brands were able to penetrate the market - even Focal got into the game now. It's just great some American brands came out with affordable, old-school style amps, like Digital Designs. I've been considering getting a DLS Class D five channel amp to simplify my system but I can't bear to let go of my DD C4.1, despite having one channel less at double the size.


*The commercial opamp-driven amps are nothing like the LM3886 kit gainclones, but that's also how opamps got a bad rep. I wouldn't have believed all the hype about Meier amps if I didn't get to hear one, and it took me a year to finally locate another one.

 

 

Quote:
Originally Posted by Artcheezzz View Post

Plus i do like a lot NAD c352 headphone 220ohm output. As far i know newer models (NAD) does not have that powerful headphone out.

 

You sure about those figures? 220ohm seems high; the old auxilliary headphone output standard is 120ohm; that could be 220mW output power. My NAD304 was "OK" with my HD600 but totally sucked with a Grado SR225. Generally your output impedance should be lower than the headphone's, and preferably, it should be 1/8 or 1/10 of it, which is why many dedicated headphone amp designs are now at less than 5ohm impedance. I've no idea what the rationale is behind 120ohms though.


Edited by ProtegeManiac - 3/13/13 at 12:33am
post #12 of 26
Quote:
Originally Posted by Artcheezzz View Post

Thanks for quick replay. One more annoying question

I like to listen default, plain music, and i need adjust ONLY treble and bass when i swap headphones (HD650 need more bass<>ah-d600 need more treble) 

Its quicker to adjust on amp, so can i leave both pre-outs and "play" with them VERY carefully?

 

You can use the 'Tone Defeat' button on the front panel to enable / disable tone controls when you're switching from headphone to loudspeaker listening.

post #13 of 26
The best upgrade you can do to those speakers is more damping material in the bass chamber and fiddling with the crossover to slightly attenuate the tweeter and upgrade the capacitors. Much cheaper than upgrading your amplifier and with way better result. The RS8's don't need huge amps either and passive bi-amping is mostly useless.
post #14 of 26
Thread Starter 

You sure about those figures? 220ohm seems high; the old auxilliary headphone output standard is 120ohm; that could be 220mW output power. My NAD304 was "OK" with my HD600 but totally sucked with a Grado SR225. Generally your output impedance should be lower than the headphone's, and preferably, it should be 1/8 or 1/10 of it, which is why many dedicated headphone amp designs are now at less than 5ohm impedance. I've no idea what the rationale is behind 120ohms though.

Thanks for good info. I hope not only me is so poor knowledge.  :)

 

Answer to this threat, becouse i`m confused now.. :)

http://www.head-fi.org/t/443721/output-impedance-questions-and-headphones


Edited by Artcheezzz - 3/13/13 at 5:00pm
post #15 of 26
Thread Starter 
Quote:
Originally Posted by eugenius View Post

The best upgrade you can do to those speakers is more damping material in the bass chamber and fiddling with the crossover to slightly attenuate the tweeter and upgrade the capacitors. Much cheaper than upgrading your amplifier and with way better result

 

I wish i would know as much as u, might be i try to do so :) I "heard" Monitor Audio RS have one of most "complicated" filters inside? Bolox?

 

 

. The RS8's don't need huge amps either and passive bi-amping is mostly useless.
That`s what i thought.. So decided to try normal bi-amp`ing. Because not many people do so, they just upgrade to newer, and not necessary better speakers. 
Just like Monitor audio old RS series is way better than new RX series.

Edited by Artcheezzz - 3/13/13 at 6:31am
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