RTiA9 Bi-Amping

Inspector 24

I've read the threads about Bi-Wiring speakers...What I'm really curious about is Bi-amping the A9's...

I've got a Parasound HCA-1206 and have tried it running off one channel at 135w but the sound just doesn't have the punch and size of running it bridged at 350w.

The current wiring setup prevents me from easily running a second pair of wires through the walls to the A9's to try bi-amping them, so I'm wondering if it has been tried with these speakers and were the results worth it, IE is giving 135w to each the woofer section and the mid/high section is better than 350w in bridged mode?

pyrocyborg

Yes, bi-amping is better than using a bridged amp, in every conceivable way. When you bridge your amp, it may create a lot of distorsion at a certain level. Also, someone will correct me if I am wrong, but it also divide the impedance by 2... so if you're using a 8 ohm speaker, it's now seing it as if it was a 4 ohm speaker. Not a big deal in some ways, but it could be if your amp isn't 2 ohm stable and you connect 4 ohm speakers.

When you bi-amp, you offer more power, like "bridging" (sorry for my english, I don't even know if it's a word), but on the other hand, this power is clearner, free of most distorsion caused by an higher load.

So yeah, it will sound better. How? Depends on your electronics, but it might wort a try: buy an amp with a 30 days back warranty, do not run your wires through yours walls but connect it directly. If you can hear a difference when compared to your bridged amp, you've got your answer. Otherwise, return your "new" amp. :cool:

But you should get something better, as the Total harmonic distorsion is almost always higher when using a bridged amp, at least, I believe.

Glowrdr

I'm sure someone else will chime in as well, but I believe the true benefit with bi-amping is really only accomplished by having an external, active crossover. Otherwise you are sending a full bandwidth signal to the speakers still, and it is still filtering the unneeded section at the speaker. If you used an active crossover BEFORE the amp, then it would be amplifying the frequency needed by the speaker, rather than everything.

But I do agree, bridging may not be the end all either. Although it's worth a shot. The upside may outweigh the downside, but you won't know unless you try.

pyrocyborg

Yes, you're right Glowrdr about the fact only an active crossover will show most benefits from bi-amping. However, when your amp alone offers 135w for a pair of RTiA9, which requires probably 250-300w per channel to sound punchy and "full sounding", adding another amp may help tame both the "distorsion issue" caused by bridging, and help deliver more power. Will it sound like a different speaker? No, because the only thing you're sending is more/cleaner power, not a power with filtered bandwidth. People sending 500w to their RTiA9/RTi12 seems quite happy with the results, as they become the most musical speaker of the RTi line. Sure, you probably won't ever need all that power, but with bi-amping, power will be there "just in case", expecially for bass as those 3 driver requires a lot of power to really shine.

It's only my opinion, but I've seen only sub-satisfactory comments about underpowered RTi12/RTiA9. Not that they are bad, far from it, but my guess is that they require a lot of power to really shine.

SolidSqual

Glowrdr wrote: »

I'm sure someone else will chime in as well, but I believe the true benefit with bi-amping is really only accomplished by having an external, active crossover. Otherwise you are sending a full bandwidth signal to the speakers still, and it is still filtering the unneeded section at the speaker. If you used an active crossover BEFORE the amp, then it would be amplifying the frequency needed by the speaker, rather than everything.

But I do agree, bridging may not be the end all either. Although it's worth a shot. The upside may outweigh the downside, but you won't know unless you try.

In some configurations such as mine, biamping is required to bypass the crossover network of the speaker. Using a digital crossover, I direct a range of frequencies to each driver set. I can do this because my amps are connected directly to the drivers, thereby bypassing the passive crossover of the speaker. The result of this configuration allows me to avoid the signal degradation introduced by many passive crossovers as well as the power normally lost by large coils, chokes, capacitors and resistors which are common in many passive crossovers. Without some modifications, you cannot bypass the crossover of the RTia9.

Despite the inability to easily bypass the passive crossover, benefits of biamping can still be realized. For example, if your favorite amps are a little weak adding a second set can help you achieve enough power to drive a particularly difficult speaker load. That being said, the extra power benefits IMO may not be worth the investment. Perhaps the best benefit of passively biamping is the ability to put tubes on the highs and solid state on the lows. If you can find a synergistic combination of these two types of amps, you can enjoy both the milky warmth of tubes and the **** kicking power of traditional solid state amps.

Mike

Inspector 24

Reducing distortion while maintaining dynamic range would be my main goal for bi-amping.

With my current amp I would be sending 135w to the mid/highs and a separate 135w to the woofers, so 270w per speaker, but does it still 'thump' as well as the full 350w/speaker that I've got now? I realize the only way to know if it satisfies me is to try it, unfortunately my configuration right now makes that tough...long wire runs through three walls...that'll be changing in the future!

In the mean time I like hearing experiences with bi-amping in this fashion. Also what people think of 270w for the A9's.

jbooker82

I guess the proper thing to do would be to upgrade to a larger amp. You can try the bi amp but it probably wont be as good as a higher powred amp hooked up normally.

pyrocyborg

As I said before, while you're bridging to get 350w, you're lowering the impedance and increasing distorsion. It is certain that bi-amping will not create those issues... but as jbooker82 said, maybe you're better off with a 250-300w amp. However, if you can't sell your current amp at a reasonnable price, then bi-amp might be an option. Also, what wire gauge do you use, and what lenght?

SolidSqual

Some more questions need to be answered. For example, do you have a dedicated 20 amp circuit? How big is your room? The reality of high watt amps is that most never see loads to justify the extra watts and and most high watt amps are not given the necessary power from the wall to approach the max output. A high wattage amp like Emotiva XPA-1 will not sound better than say a Pass Labs XA30.5 which puts out considerably less wattage. In addition, you would need a dedicated circuit to achieve anywhere near the stated output of the Emotiva. Quality over quantity is the name of the game when talking about watts.

Inspector 24

jbooker82, why wouldn't bi-amping work as well as a single amp? 135w to the mid/high and 135w to the woofers means the speaker is seeing 270w...for arguments sake, wouldn't that be the same as 270wpc from another otherwise equal amp?

Pyrocyborg, agreed on the subject of distortion. I gave the amp another chance in un-bridged with a wider variety of music and found it wasn't as bad as I previously though. Jazz music certainly improved with all it's subtleties and softness, sounds became more distinct and clear, however in playing big loud records like Audioslave it did loose a little size, though not enough to worry about. Still plenty of volume to keep me happy! Wiring is 12ga banana plugged, but about 50' run through the walls right now. That is going to be changing to about 15' runs, possibly shorter once I get the setup re-done.

SolidSqual, no dedicated circuit yet, basement has two 15A circuits which are powering the amps. I have plans to run a dedicated circuit along with the other wiring changes. Room is 34x17x8.

jbooker82

Inspector 24 wrote: »

jbooker82, why wouldn't bi-amping work as well as a single amp? 135w to the mid/high and 135w to the woofers means the speaker is seeing 270w...for arguments sake, wouldn't that be the same as 270wpc from another otherwise equal amp?.

The woofers are the power hogs. The midrange and tweeter will not use near the power the 4 woofers will.

Say the top (two mids, and 1 tweeter) section only takes 50 watts to maintain a given volume. You have 85 watts of unused power. The 4 woofers would only have 135w on hand. The 85w that isnt being used is not avalable for the woffers because they are operating on their own circuit. Where if you had them hooked up with a 270w x 2 channel amp they would have 220 watts on tap.

That is why the whole bi amping thing to increase the power to the speaker is a bogus sales gimic. You can add a second amp but your not going to double the power to the speakers.

ravaneli

Just one note, the impedance will not change when biamping. Impedance would change if you have two speakers to the same channel, but that is the opposite of what you are doing. Note that I say speaker, not driver.

Inspector 24

jbooker, good point about the woofer vs mid and high power needs. Hadn't considered that one! So I may have to turn down the mid/high channel to balance things out...thus not getting a full 270 watts of output anyway...thus better to have a single 270w amp?

Makes sense if that's the case...

Inspector 24

Well nuts to me, got a deal on a Parasound HCA-2003. It's rating of 200wpc is apparently conservative as the later model 2003a is rated at 220, but is identical but for a 12v trigger input. Guess we'll see how this works!