RTI A7 Bi Amp Impedance / Resistance

jbooker82

What is the impedance or resistance of a Polk RTI A7 that have been bi amped. Does it still stay the same of 8 ohms or is it lower / higher?

I was just wondering becauce my Onkyo 808 has a setting for speaker resistance. I only have 2 choices 4 ohms or 6 ohms. It says to use 6 if they are 6 ohms or more.

Thanks for your time.

josh

PrazVT

I'm pretty sure that it's still 8 ohms. The upper binding posts are for the midrange / tweeter and the lower binding posts are for the woofers.

tonyb

Yeppers, set to 6 and run with it.

F1nut

Bi-amping with an AVR is a complete waste of time. Bi-amping requires separate amps using separate power supplies, not a shared one like your AVR. It also requires the use of external active crossovers.

jbooker82

Alright thanks for the help and time.

jbooker82

F1nut wrote: »

Bi-amping with an AVR is a complete waste of time. Bi-amping requires separate amps using separate power supplies, not a shared one like your AVR. It also requires the use of external active crossovers.

Well I just figured I mght as well since I am not currently using the rear suround terminals.

ben62670

You are better off using just the front channels and some better speaker cables instead of 2 sets of cheaper wire.

mdaudioguy

^^ I'm not sure better speaker wire will make an evident improvement any more than bi-amping with an AVR, if the use is only for HT. He didn't say, but I'm making a guess. I can tell a difference with music, but HT - not so much.

tonyb

jbooker82 wrote: »

Well I just figured I mght as well since I am not currently using the rear suround terminals.

In a receiver,generally speaking, you have more power with the least amount of channels running.

FTGV

Since your reciever has the capability I say give it a try,just don't expect big sonic improvements.What you gain with this type of "passive" biamping is a few extra db of power headroom.

jbooker82

I didnt hook it up regulary. I had all the wiring / biamping and avr hooked up yesterday. That way when the speakers were droped off today I just had to hook them up. I have not herd the speakers hooked up regulary with one set of cables.

Right now I just have the Onkyo 808, 2 Polk RTI A7's and a DSW Pro550wi sub. Just started piecing my HT together as cash allows. I just wanted to get away from the TV speakers and didnt want the all in 1 box kits. I also plan on using it for music (radio, Ipod, internet radio, sirius/xm). Nothing super serious.

I do have Monser 12 gauge speaker wire with monster banana plugs. 2 sets of 12 gauge monster cable going to each speaker looks like I am using jumper cables for speaker wire.

I am considering going down to a smaller monster speaker wire. What gauge is the XP and the XPHP?

Thanks again for all the replys

tonyb

Nothing wrong with 12 ga but you only need one run to each speaker. Just make sure the jumpers are put back in between the speaker posts if you go back to one run of cable. Since you using a sub for the lower bass, why are you bi-amping, or even what are you bi-amping ? What do you have the sub crossed over at in the receiver ?

jbooker82

Bi amping is when you use 2 different amps or channles to power one speaker. One channel is used for mid and highs. The other is used to drive the woofers. The best case senerio would probably be useing two different amps, or a real 4 channel amp. That way you can adjust the gian for each channel. I just done it with my reciever because I figured it wouldn't hurt.

This is what I have been told about the sub:
I have the sub set a 120 hz. That is what it came set at and the automatic setup put it to. I have been told that the AVR doesnt have a cross over for the sub. It is supose to be a low pass filter. The LFE contains sounds that are designated to LFE from 120 hz and lower. Since it is supose to be a low pass filter it wont send audio that is above the setting to the towers you loose the sound.

I did the setup twice. The first time I adjsuted the subs volume to 75 db by using the volume on the sub. I had problems with the sub turning off. It wasnt getting a strong enough lfe signal to keep it on. So I ran the auto setup again with the sub volume set at 65 db and it set the sub volume / gain adjustment in the reciever to +6 db. Where as before with running the setup with the volume adjusted to 75 db it backed the LFE Gain down to -3

It also set my two RTI A7's to 40 hz.

mantis

F1nut wrote: »

Bi-amping with an AVR is a complete waste of time. Bi-amping requires separate amps using separate power supplies, not a shared one like your AVR. It also requires the use of external active crossovers.

From your stated comments I'm assuming you did this and is a complete waste of time why?
I have never even attempted to bi amp from a receiver so I have no experience with this setup. I'm curious in your findings here.

Many newer avr's today are offering Bi amping the front channels. I'm assuming their has to be some benefits from that?

nguyendot

mantis wrote: »

From your stated comments I'm assuming you did this and is a complete waste of time why?
I have never even attempted to bi amp from a receiver so I have no experience with this setup. I'm curious in your findings here.

Many newer avr's today are offering Bi amping the front channels. I'm assuming their has to be some benefits from that?

They offer it because most people don't actually set up 7.2 channels - they prefer the 5.1. So that the customer doesn't feel like they're losing two channels of amplification that they paid for, they give you the option of bi-amping the front channels, or running another zone. It's just a feature. There is no sonic benefit, as when you turn those two channels on you reduce the amount of power drastically for about 95% of receivers out there.

F1nut

Bi amping is when you use 2 different amps or channles to power one speaker. One channel is used for mid and highs. The other is used to drive the woofers. The best case senerio would probably be useing two different amps, or a real 4 channel amp. That way you can adjust the gian for each channel.

Many newer avr's today are offering Bi amping the front channels. I'm assuming their has to be some benefits from that?

As I stated the basic principals of bi-amping require separate amps using separate power supplies. It also requires the use of external active crossovers. Without bypassing the passive crossovers, you are not bi-amping, period.

FTGV

F1nut wrote: »

Without bypassing the passive crossovers, you are not bi-amping, period.

Thats why it's called passive bi-amping.Certainly active biamping with separate amplifiers is a much better approach.

F1nut

Thats why it's called passive bi-amping.

Which is nothing more than a pseudo attempt at the real thing.

tonyb

F1nut wrote: »

Which is nothing more than a pseudo attempt at the real thing.

Bingo....

Think of a car as a speaker and the engine as the amp. Can that car perform as well with the engine powering 2 cars,3 or 4 cars ? When it comes to receivers, the less channels used, the better.

Passive bi-amping from a receiver, I think was made up to support a sales pitch, a marketing idea, to the masses.

FTGV

FTGV wrote: »

.Certainly active biamping with separate amplifiers is a much better approach.

F1nut wrote: »

Which is nothing more than a pseudo attempt at the real thing.

Thus the intent of the other half of my post.

jbooker82

Well I hooked them up regular last night. I couldn't really tell a difference. I will just leave them like that since the less channels you run the more wattage the avr puts out.

Ridewithme38

jbooker82 wrote: »

What is the impedance or resistance of a Polk RTI A7 that have been bi amped. Does it still stay the same of 8 ohms or is it lower / higher?

josh

I have the same question, sorta, so i bumped an old thread, hope that ok?

It appears the rear terminals on the RTi A7 are bridged in parallel. If it reads as 8ohms when bridged in parallel, wouldn't that mean that each terminal is 16ohms just by itself?

[Deleted User]

Hello,
Welcome to Polk's forum. There is a passive circuit, inside the speaker, that isolates each section of the speaker from the other. This circuit, called a crossover, divides the incoming electrical signal into two frequency bands, one of around 2,000Hz and higher and the other band around 2,000Hz and lower. So, this division means that the impedance remains at around 8 ohms whether or not the jumper plates are connecting the two sections.
I hope this is helpful information.
Ken

B67

Hi,

I am from Holland and I read it all.

Bi amping is not the option. I use Oelbach 14 ag cable (copper) and replaced the jumpers by Van der Hul Snowline (silver) on my RTI A7 speakers. The crosssover is 40 Hz, damn the sound is great. Many friends say that is sounds if you are there on the stage.

I can tell you one things. It's sounds great, nice rich bass en very open in the high range.
My AVR is the Marantz SR 6009. My favorite selection is Pure Direct.

Greeting,

Burt

K_M

tonyb wrote: »

F1nut wrote: »

Which is nothing more than a pseudo attempt at the real thing.

Bingo....

Think of a car as a speaker and the engine as the amp. Can that car perform as well with the engine powering 2 cars,3 or 4 cars ? When it comes to receivers, the less channels used, the better.

Passive bi-amping from a receiver, I think was made up to support a sales pitch, a marketing idea, to the masses.

One gas tank powering 4 engines, in 4 separate cars?

Hah, is that more accurate?

Either way, like many things in audio, marketing maybe.
I would like to hear from several that have actively tried it, and their conclusions.

With many audio related things, gains have been made, where they seem to make no logical sense, so not sure we should discount this either.
Often what the listener thinks they hear or expect to hear, trumps what is going on in reality, or in what makes logical sense.

So, ya never know!

gce

K_M wrote: »

I would like to hear from several that have actively tried it, and their conclusions.

I had a pair of RTiA7's powered by an AVR. I to was curious what bi-amping would do so I tried it. It did NOT improve anything. They speakers sounded the same. The only good thing that came out of it is now I know you can't gain improvements by bi-amping with an AVR.

don0

Either bi-amping or bi-wiring my speakers seems to make the tweeters sound a little better on some female voices, especially on classical or opera music.
I believe it is because the high current of the woofers do not reach the tweeters.

nguyendot

The current is pulled from the same power supply in the receiver. Bi-wiring won't improve anything in the way you're describing, as the current is not only coming from the same power supply, but the same terminal jacks even - to the same amps.

F1nut

If you want real sound improvement with the RTi A7's, a crossover upgrade is the answer.

K_M

nguyendot wrote: »

The current is pulled from the same power supply in the receiver. Bi-wiring won't improve anything in the way you're describing, as the current is not only coming from the same power supply,but the same terminal jacks even - to the same amps.

You are confusing "Bi-Wiring", with "**Passive**Bi-Amping", which actually does use 2 separate amplifiers, and a separate wire, but one power supply.

tonyb

K_M wrote: »

[Either way, like many things in audio, marketing maybe.
I would like to hear from several that have actively tried it, and their conclusions.

With many audio related things, gains have been made, where they seem to make no logical sense, so not sure we should discount this either.
Often what the listener thinks they hear or expect to hear, trumps what is going on in reality, or in what makes logical sense.

So, ya never know!

If you do a search, you'll find many who have tried it, some do like it but I have to say the majority didn't and thought it a waste of time.

When trying to use logic in a subjective field such as audio, you'll never get cut and dry answers. Most want that though, out of fear of wasting their money. Impossible to do though.

You have to get in the game, dive in and try a few things for yourself. Like buying a pair of shoes. You have to try on a few pairs to see what fits.