bi amping

jeremie

So considering bi amping my 707s. So I removed the jumpers to check impedance. The bottom is 6.8 and the top post does not show anything. When I add the jumpers it show 6.8. What am I missing here?

F1nut

You're not measuring the impedance, that's the resistance.

FTGV

jeremie wrote: »

So considering bi amping my 707s. So I removed the jumpers to check impedance. The bottom is 6.8 and the top post does not show anything. When I add the jumpers it show 6.8. What am I missing here?

With bottom posts you are measuring the DC resistance of the woofers voice coil and any inductor in series with it. The nominal AC impedance will be aprrox. an ohm or 2 higher. Series capacitor(s) are preventing you from getting a resistance measurement on the top posts.

jeremie

So no concerns running 150 watts to each the upper and lower post? Also, what ohm would my amp see? 4 or 8 at each post

FTGV

jeremie wrote: »

So no concerns running 150 watts to each the upper and lower post?

No problem but the sonic benefits of passive bi amping are highly debatable.

Also, what ohm would my amp see? 4 or 8 at each post

Since there is a crossover network the impedance of two sections will be independent of each other. In other words they will not appear as a parallel load to the amp. Even though fed the full range signal ,essentially the tweeter amp will only see the impedance of the hi pass section and woofer amp will only see the impedance of the woofer section.

FTGV

.....

FTGV

jeremie wrote: »

So no concerns running 150 watts to each the upper and lower post?

I forgot to mention that the amplifiers need to have identical gain or you will end up with a frequency imbalance.

jeremie

Looking at the outlaw 5000. It’s five channel. Was going to do 4 channels to the fronts bi amped and one to the center.

TNTsTunes

120 x 5 at 8 ohms??? That's all the power you want to make 707's sing??? They only have a sensitivity rating of 88db....

That hardly worth the effort. It's not like bi-amping them is going to increase the sound output. An amp that puts out 250-300 watts or more that is bi-wired would be a much better choice.

jeremie

I was considering the emotiva 3 channel

jeremie

@TNTsTunes wouldn’t bi amping the 5000 be 240 or so watts per speaker?

F1nut

jeremie wrote: »

@TNTsTunes wouldn’t bi amping the 5000 be 240 or so watts per speaker?

No, because almost all of the 120 watts you are sending to the tweeter is wasted as the tweeter might use 5 or 10 watts.

jeremie

Got it, thank you for explaining. Will look for something with a little more power.

rpf65

Get a Parasound 2250, forget bi-amping, add quality jumpers, and call it a day.

That should make your ears very happy.

jeremie

But I want to power my center as well. My Yamaha 3020 will drive the remaining 8 speakers.

Oldschool59

Jeremie, In my humble opinion, Your 2nd Choice after your Parasound deal fell through, the Outlaw 5000 is the better value between the Outlaw and Emotive.
There is a nice review on Audioholics website on that 5000. If you get the time go check it out. Also there is this monolith amp made by ATI. Them dudes been putting out some nice gear for a very long time. Monoprice is using them dudes to build their amps now. Actually in my opinion, Outlaw and Monoprice aka. Monolith amps are your Best values out there "new" that is. Parasound 3 channel " New" are the best value amps there just a lil more in bucks above or right at the Monolith. What You pay in price for new you get the 5 year warranty with all three. So something to consider.

jeremie

Confused, so one person says the 5000 will work and one says it won’t have enough power. I did read the review and that’s one of the original reasons I was looking at it. But then hearing bi amping might not be the best route concerns me. Why does polk give you the ability if you shouldnt use it.

Oldschool59

I have asked myself that very same question for years not just with Polk but with most other manufacturers. Why even put jumpers to "Bi-amp" when in fact it really isn't a true Bi-amping. Maybe one of the old timers on here will jump in and help you, me and everyone else get a better understanding of removing the "jumpers"..I believe I read somewhere about that but I slept since than. I do know this, F1NUT, and a few of the other old timers on here are a wealth of knowledge and have a ton of experience on this very subject. But who knows really why the engineer designers even do that.

motorhead43026

^^Because it sells, that's why.

It is what people want. Oh looky, two sets of binding posts.

Oldschool59

^^^motorhead43026,
Lol...well said...if I remember that's the conclusion I came up with when I was researching that back in the day.

I would bet my last samwich it has to do with some 'Market Guys aka..PR research dude that went into the lab and made some engineer pretty mad when he came up with that idea.

TNTsTunes

jeremie wrote: »

Confused, so one person says the 5000 will work and one says it won’t have enough power. I did read the review and that’s one of the original reasons I was looking at it. But then hearing bi amping might not be the best route concerns me. Why does polk give you the ability if you shouldnt use it.

IMO they give you the posts so you can bi-wire the speaker.

Ever had a pair of speaker cables that have great highs but lack bass and cables that have great bass but are thin up high?

Most of my amps have two sets of speaker connections per channel too.

Combine those two sets of cables in a bi-wired configuration and the end result is a speaker that sounds great up high and down low.

Some cables are designed for bi-wiring and have different current paths for the high pass and the low pass.

About the best reason to bi-amp a speaker is to protect the tweeters from a clipped signal caused by bass notes. Having not enough power/current is the cause of this.

If I want to drive speakers hard I want an amp that produces about 25% more power then the speakers are rated at. This way the amp is never straining, it's just clean and clear at obscene volume levels. Lot's of headroom is a great thing.

Msabot1

I'll make it simple..You have a multi channel receiver with a SHARED power supply..what you are attempting is not true bi amping...Google Bi Amping and read up on what it entails..somewhat more complex than what you are trying to do..just a friendly suggestion....

jeremie

Actually looking to bi amp an amp, not my 3020.

jeremie

That being said I am going to buy a 3 channel amp. Emotiva or monolith.

tonyb

Jeremie,

The guys are correct, don't waste your coin bi-amping in the sense marketing dictates. When you add an amplifier, it doesn't automatically throw out it's rated power the second you turn it on. An amplifier stores power, then releases it when the volume and source material dictate, ask for it. Takes some good reserve power to reproduce those sharp stop and go passages in certain music/movies.

The 707's are fairly easy to drive too, so you don't need gobs of power. Anything upwards of 150 from a decent power amp should suffice. If your room is extra large, I'd throw 2-250 watts at 'em.

DarqueKnight

jeremie wrote: »

Confused, so one person says the 5000 will work and one says it won’t have enough power. I did read the review and that’s one of the original reasons I was looking at it. But then hearing bi amping might not be the best route concerns me. Why does polk give you the ability if you shouldnt use it.

Why does a car have 120 mph on the speedometer if you shouldn't use it?

It's not that you shouldn't ever go 120 mph, it's that 120 mph wouldn't be practical, or safe, in most situations. Also, an engine that can do bursts of 120 mph can do 80 mph all day.

My results with biamping have been mixed...depending on the amps and speakers involved. I have generally obtained best results with a higher quality stereo amp and higher quality jumpers than with speakers horizontally biamped with identical speakers.

The exception to this is my Polk Audio LSiM 706C center channel speaker. It exhibits more clarity, detail, and sonic weight being vertically biamped with a single Adcom GFA-565SE than being jumpered and driven from one channel of the 565SE.

Are you clear on what performance improvements you hope to gain from biamping?

jeremie

DarqueKnight wrote: »

jeremie wrote: »

Confused, so one person says the 5000 will work and one says it won’t have enough power. I did read the review and that’s one of the original reasons I was looking at it. But then hearing bi amping might not be the best route concerns me. Why does polk give you the ability if you shouldnt use it.

Why does a car have 120 mph on the speedometer if you shouldn't use it?

It's not that you shouldn't ever go 120 mph, it's that 120 mph wouldn't be practical, or safe, in most situations. Also, an engine that can do bursts of 120 mph can do 80 mph all day.

My results with biamping have been mixed...depending on the amps and speakers involved. I have generally obtained best results with a higher quality stereo amp and higher quality jumpers than with speakers horizontally biamped with identical speakers.

The exception to this is my Polk Audio LSiM 706C center channel speaker. It exhibits more clarity, detail, and sonic weight being vertically biamped with a single Adcom GFA-565SE than being jumpered and driven from one channel of the 565SE.

Are you clear on what performance improvements you hope to gain from biamping?

Was looking towards affordability. Outlaw 5k 599 vs 1200 of the emotiva.

Oldschool59

Jeremie, How are you digging them LSiM's?
Man if I had a pair of them 707's, I believe I would have taken one of the lower drivers out just so I could get a whiff of that new speaker smell, take a flashlight look around under the hood you know what I mean? From what I have read from the reviews, the upper-end is very sweet with that Vifer tweeter.

jeremie

@Oldschool59 only listened to them for about 30 min, then wrapped them up until I finish the room. Very impressed so far.