V3 Fosi mono Kappa 9

[PENG]

I had an 8B bridged 2 by 400 watts. It was not happy. Light up red and even clipped out.

That's expected, one should never run such amps bridged, to drive Kappa 9s!!!!

It doesn't matter if you have a 150 lbs Krell or Passlab, don't bridge them to drive 4 ohm nominal speaker especially those dip below 2 ohms. Again, that, as a rule (there's always exceptions) is a no no.[/QUOTE]

I have (downstairs setup) 2 svs mixed one PB2000 and another PB1000 for 1st octave when listening in 2 channel so well aware of svs and subs helping out. On the INFINITY's I have a monitor audio sub doing 25hzto40hz then cut off. I wish I could loop the signal but it doesn't release the entire signal so it is tuned in by ear to just dissapear.

So far the V3's are really shining. I have played a lot of house and techno music and they can really go. So, so far very pleased!

Congrats!

 

[Anglofun]

That's expected, one should never run such amps bridged, to drive Kappa 9s!!!!

It doesn't matter if you have a 150 lbs Krell or Passlab, don't bridge them to drive 4 ohm nominal speaker especially those dip below 2 ohms. Again, that, as a rule (there's always exceptions) is a no no.

Congrats!
[/QUOTE]
By bridged I mean instead of 4 by 125 watts, I do 2 by 400 watts. You think this is problematic?

 

[PENG]

By bridged I mean instead of 4 by 125 watts, I do 2 by 400 watts. You think this is problematic?

To get 2X400 watts you are still bridging aren't you? To me, if you don't bridge the 8B, each channel is rated 120 W into 8 ohms.

When you bridge 2 of the 4 channels, you will get 400 W into 8 ohms. They warn you that when bridge, use 8 ohm nominal loads, but in theory, if you use the amp in a responsible why (such as be careful with the volume dial), it is okay to drive 4 ohm speakers but only safe to do so if you don't exceed 200 W.

That also means in theory, you can drive the Kappa 9 that way, but keep the volume low enough to make sure the amp won't try to push more than 100 W but that obviously would defeat your purpose of wanting more "watts".

To keep it simple for now, suffice to remember, with low impedance loads such as your speakers, you need to focus on current, but for higher impedance speakers, voltage would become the most important thing to consider, and if you have loads like the Kappa speakers, you still need to consider voltage if you listen loud and/or sit far, otherwise focus more on current could be enough.

Watts is the wrong term, and you wonder why I posted so many times about people should consider/calculate their voltage and current requirements, instead of power, but the reality is, most consumers, even those who frequent audio forums, don't understand much more about power/watts.

 

[ski2xblack]

...[bridged amps]...You think this is problematic?

Oh, yeah. Bridged amps see the load halved, so those 1 ohm dips appeared as 1/2 ohm to your Bryston. It's not at all surprising that that triggered protection circuitry.

 

[Anglofun]

To get 2X400 watts you are still bridging aren't you? To me, if you don't bridge the 8B, each channel is rated 120 W into 8 ohms.

When you bridge 2 of the 4 channels, you will get 400 W into 8 ohms. They warn you that when bridge, use 8 ohm nominal loads, but in theory, if you use the amp in a responsible why (such as be careful with the volume dial), it is okay to drive 4 ohm speakers but only safe to do so if you don't exceed 200 W.

That also means in theory, you can drive the Kappa 9 that way, but keep the volume low enough to make sure the amp won't try to push more than 100 W but that obviously would defeat your purpose of wanting more "watts".

To keep it simple for now, suffice to remember, with low impedance loads such as your speakers, you need to focus on current, but for higher impedance speakers, voltage would become the most important thing to consider, and if you have loads like the Kappa speakers, you still need to consider voltage if you listen loud and/or sit far, otherwise focus more on current could be enough.

Watts is the wrong term, and you wonder why I posted so many times about people should consider/calculate their voltage and current requirements, instead of power, but the reality is, most consumers, even those who frequent audio forums, don't understand much more about power/watts.

Well noted!

 

[TLS Guy]

May be that's what people said on the internet but they often said such thing without stated the underlying conditions.

Reality is, such large speaker can be considered power hungry but most of the times there are not if used for less than reference level (like most people do) and seating distance not too far such as less than 4 to 5 meters.

Take a look of the specs, assuming yours are the RS 9 Kappa

View attachment 76520

If you know how to calculate the power requirements, that's great but if not, just use an online calculator and you will see that with just 20 W, you can get reference level of 105 dB, that's super loud! from 15 feet:

Peak SPL Calculator

So, those who said they were horrid to drive, might be sitting very far in a very large room and/or listen to even above reference level.

Having said that, I don't believe the 102 dB/1w/m is realistic, so I would de-rate it by 13 dB, to say 89 dB and the results would then be:

about 90 dB, from 15 feet, 25 W, or
92 dB, from 12 feet, 25 W, or
105 dB (ref level), 12 feet, with 500 W

You can see that there is truth in the speaker being "horrid to drive" as a general statement, one must know the use case and go from there, and keep in mind I arbitrarily de-rate the sensitivity spec from 102 dB to 89 dB, so in reality, I doubt most would need 500 W from 25 feet to get reference level.

Also, your proposed use case is to use the V3s to drive the 2 12 inch woofers only, so your power requirement would drop below the calculated results shown above.

Such large 4 ohm rated speakers of love "power" or current, but how much you need depends a lot on how loud you want to listen to and your seating distance.

Then that Kappa 9 is yet another in the long list of incompetently designed speakers. You can NOT make a decent speaker with a passive crossover at 80 Hz. I have done a lot of investigation of this in my time, as have others. 400 Hz really is the lower limit of a passive crossover. When you go lower than that all kinds of havoc starts to occur, and they become amp busters. That low 1 ohm impedance is absolute evidence of a crossover resonating. That is a massive amp stress. You have trouble with your midrange because of that incompetent design
With a crossover at 80 Hz then a totally active crossover is mandatory, yes, mandatory. There is NO acceptable passive solution for a crossover that low.
That is why all subs that are in any way sane designs use active crossovers, which is the sub out of an AVR or or AVP. That is why it is done that way.

If you want to salvage those speaker, then you need to disconnect the bass drivers from the low pass filter and connect the bass drivers directly to your power amp.

Then you need to modify the crossover in the speakers and just keep the high pass section between the mid and tweeter. Then set the bass management crossover on your AVR or AVP, probably in your case an AVP.

The you will have an acceptably engineered speaker and not an absolute abortion of one.