Nominal impedance with double terminals
- Thread starter TLS
- Start date
Quite so, but what with 2 different amplifiers in a bi-amping situation?
Chops54
pfm Member
Sorry, brain malfunction LOL.
Right, if you passive biamp the speaker ie drive the speaker with separate amps into each half of the crossover then yes each amp will see a different impedance from the nominal.
The impedance of the tweeter section increases as frequency decreases and the impedance of the woofer section increases as frequency increases. As impedance rises the load on the amp is reduced and visa versa.
Right, if you passive biamp the speaker ie drive the speaker with separate amps into each half of the crossover then yes each amp will see a different impedance from the nominal.
The impedance of the tweeter section increases as frequency decreases and the impedance of the woofer section increases as frequency increases. As impedance rises the load on the amp is reduced and visa versa.
Darth Vader
From the Dark Side
Your amps will see a lighter load. This may be good as 'nominal' is just that. My speakers are 6 Ohms nominal but hover around 2 Ohms in the treble region.
Depends on the speaker and crossover design but overall easier to drive. I cannot separate my 3-way design so have to employ hefty amplification to get best results.
Cheers,
DV
Depends on the speaker and crossover design but overall easier to drive. I cannot separate my 3-way design so have to employ hefty amplification to get best results.
Cheers,
DV
demotivated
pfm Member
An 8 ohm bass section is 8 ohms up to the xover, then it goes higher...etc..
martin clark
pinko bodger
Since a 'biwirable' crossover is electrically complementary, the nominal impedance should be expected to stay the same. 8ohms single-wired should be expected to remain 8ohms in each half after splitting.
The fact it may not is down to speaker designers and their own cavalier assumptions about voltage sources...
The fact it may not is down to speaker designers and their own cavalier assumptions about voltage sources...
That means both halves would have common ground and that would blow up some amplifiers because they cannot be runned in parallel!
martin clark
pinko bodger
TLS - no it doesn't... bi/tri-wirable crossovers split out 0v returns also.
In any case all voltages are differential
In any case all voltages are differential
TLS - no it doesn't... bi/tri-wirable crossovers split out 0v returns also.
In any case all voltages are differential
If you mean that high pass and low pass are arranged independently in such a way that impedance is the same then I understand what you mean by electrically complementary.
Sorry but I am trying to figure out why some people say that passive bi-amping does not improve sound quality.
demotivated
pfm Member
Not exactly.
In a simple first order ''normal polarity'' crossover, the positive signal is split. One end of the positive signal goes to the capacitor then goes to the + terminal on the tweeter. The other end of the positive signal goes to the inductor then goes to the + terminal on the woofer. Both have a common ground (negative) that is connected to the negative side of the binding post.
If you add a second set of binding post, the negative from the tweeter and the negative from the woofer is separated.
Martyn Miles
pfm Member
I know its radical, but does bi-wiring actually work ?! Most of my early spkrs. had single terminals, eg BC1s. My Rogers Studio 3s had double, but the previous owner has 'jumped' them with cable. My Harbeth LS3/5as are double, so I did the Studio 3 thing. By the way, I recall Alan Shaw of Harbeth 'poo-pooing' bi-wiring. So did he fit two sets because of market pressure ? My brother has bi-wiring facility on his amplifier, so when he borrowed my Studio 3s he bi-wired. OK, unfamiliar system, but I couldn't detect a difference... Martyn .
demotivated
pfm Member
What happen if one use two identical amplifiers in a bi-amp situation. Some amplifiers double their output with halving of impedance. (4Ohm vs 8Ohm)
Wouldn't that result in a unbalanced sound if the tweeter amplifier see a 8Ohm load and the woofer amplifier see a 4Ohm load?
Darth Vader
From the Dark Side
I'm afraid that you don't understand. There is nothing wrong with that.
The impedance of a complex speaker varies all over the place. As I have already said mine go from 6 up a bit and down below 2 Ohms. It doesn't matter a fig. Think of the impedance like traveling along a road. You go on the flat up the hills and down the valleys. A car with a bigger engine handles both the hills and valleys better. More power to go up and better braking effect of the engine gong down.
So its the amp thats more important than than the impedance. In fact its very important to control the transducers going up the hills and down the valleys.
Speakers are around 1% efficient. You lose say 10-15% in the crossover components and the rest as heat in the transducers. The voice coils can easily reach 150 degrees and often more........... This heats up the innards of the speaker case and changes the values of the crossover components etc. But do we worry about it? Nah!
I'd go for one bigger and more powerful amp. I use two bridged amps that can deliver >1600wpc! The sound? Dynamic and really really good.
Cheers,
DV
PS Please don't confuse impedance with resistance. In the latter current and voltage are synchronised in the former current lags in an inductance and leads in capacitance. So 'Watts' are not what you think they are....... thats why you'll often see VA ratings on Xformers and not Watts.
The impedance of a complex speaker varies all over the place. As I have already said mine go from 6 up a bit and down below 2 Ohms. It doesn't matter a fig. Think of the impedance like traveling along a road. You go on the flat up the hills and down the valleys. A car with a bigger engine handles both the hills and valleys better. More power to go up and better braking effect of the engine gong down.
So its the amp thats more important than than the impedance. In fact its very important to control the transducers going up the hills and down the valleys.
Speakers are around 1% efficient. You lose say 10-15% in the crossover components and the rest as heat in the transducers. The voice coils can easily reach 150 degrees and often more........... This heats up the innards of the speaker case and changes the values of the crossover components etc. But do we worry about it? Nah!
I'd go for one bigger and more powerful amp. I use two bridged amps that can deliver >1600wpc! The sound? Dynamic and really really good.
Cheers,
DV
PS Please don't confuse impedance with resistance. In the latter current and voltage are synchronised in the former current lags in an inductance and leads in capacitance. So 'Watts' are not what you think they are....... thats why you'll often see VA ratings on Xformers and not Watts.