Speaker Load; Crazy Connection - Need Help!

[pjrake]

Okay, so this is my crazy onstage connection (or at least the idea that I have). High gain amp going to the RIVERA Silent Sister ISO cab (to feed the FOH guy a nice signal). Then for my "stage monitor" a 212 cab (celestian v30's) and in-between that a RIVERA Rockcrusher. My amp is set for the "sweet spot" which means master and channel gain close to 12 o'clock (stupid loud under normal circumstances, but oh does it sound amazing!).

So, my question is: will I damage any of my gear if I have it set up this way (don't know much about speaker ohm and load impedence

4 ohm out from the amp (parallel) = 1) to RIVERA Silent Sister (8ohm cabinet). 2) to RIVERA Rockcrusher set to 8ohm to a 212 cabinet (8 ohm mono).

I thought that if you run in parallel it's the ohm divided by the number of cabinets: 8/2 so 4 ohm in my case. Does this mean it's sending 4 ohm load to EACH CABINET. The reason I'm asking is because the Rockcrusher's manual says: "DO NOT USE THE ROCKCRUSHER ON AMPLIFIERS THAT ARE HARDWIRED FOR 2 OR 4 OHMS, OR DO NOT HAVE 8 OR 16 OHM OUTPUT IMPEDANCE CAPABILITY. DO NOT USE THE ROCKCRUSHER WITH ANY SPEAKER LOAD LOWER THAN 8 OHMS IMPEDANCE."

If anyone can help me that would be awesome!

PJ

PS: Or I can just get an Axe FX lol

 

[glpg80]

I do not know what the rockcrusher is, but i can tell you that there is a variable called impedance reflection. You do not send impedance as an output, impedance is resistance in the imaginary plane as it is an opposition to current flow based on phase correlation.

You cannot do what you want to do because the rock-crusher will not see the intended impedance of 8ohms on the secondary of the output transformer. The amplifier would be happy to run with this setup however the rock-crusher would not. I do not know or understand what the rock-crusher is, but it specifically says not to have a 4 ohm secondary connection and that is exactly what you would be doing in order to run two 8 ohm sources in parallel on the secondary of the output transformer of the amplifier.

In simpler terms no you cannot. Amplifier would be fine, but the rock-crusher was not designed or intended to be ran in parallel with another reactive device where impedance reflection comes into play.

 

[pjrake]

I do not know what the rockcrusher is, but i can tell you that there is a variable called impedance reflection. You do not send impedance as an output, impedance is resistance in the imaginary plane as it is an opposition to current flow based on phase correlation.

You cannot do what you want to do because the rock-crusher will not see the intended impedance of 8ohms on the secondary of the output transformer. The amplifier would be happy to run with this setup however the rock-crusher would not. I do not know or understand what the rock-crusher is, but it specifically says not to have a 4 ohm secondary connection and that is exactly what you would be doing in order to run two 8 ohm sources in parallel on the secondary of the output transformer of the amplifier.

In simpler terms no you cannot. Amplifier would be fine, but the rock-crusher was not designed or intended to be ran in parallel with another reactive device where impedance reflection comes into play.

Thanks!

The RIVER Rockcrusher is an attenuator/load box. So I would have one speaker line running to the RIVERA ISO cab, and the other to the 212 cab (with an attenuator in-between).

PJ

 

[glpg80]

You already said that PJ - i already answered - it cannot be done regardless what it is. The last line explains why.

 

[pjrake]

You already said that PJ - i already answered - it cannot be done regardless what it is. The last line explains why.

I understand, and I appreciate your time. My last reply was just clarification (for me), and what the Rockcrusher is.

Thanks!

PJ

 

[mjtripper]

The rock crusher impedance doesn't have to match on the front and back. The input needs to be 8 or 16 from your amp but then just plug both speaker cabs into the rock crusher which will handle a 4 ohm speaker load. What it won't do is function as a 4ohm load. Set the amp to 8 and the rock crusher to 8 then plug both cabs in to the two speaker outs on the rock crusher. This is how I use it after talking to Rivera about it, just call them or shoot them an email to be sure. I have a 8ohm silent sister and a 8ohm k212 plugged into it.

 

[pjrake]

The rock crusher impedance doesn't have to match on the front and back. The input needs to be 8 or 16 from your amp but then just plug both speaker cabs into the rock crusher which will handle a 4 ohm speaker load. What it won't do is function as a 4ohm load. Set the amp to 8 and the rock crusher to 8 then plug both cabs in to the two speaker outs on the rock crusher. This is how I use it after talking to Rivera about it, just call them or shoot them an email to be sure. I have a 8ohm silent sister and a 8ohm k212 plugged into it.

That is almost the exact same setup as mine! However, the way you have yours setup wouldn't the Rockcrusher attenuate BOTH the k212 and the Silent Sister? The way I'm thinking is having a "monitor" on stage (the 212) which I can adjust during a set without affecting the Silent Sister and the FOH settings.

PJ

 

[glpg80]

The rock crusher impedance doesn't have to match on the front and back. The input needs to be 8 or 16 from your amp but then just plug both speaker cabs into the rock crusher which will handle a 4 ohm speaker load. What it won't do is function as a 4ohm load. Set the amp to 8 and the rock crusher to 8 then plug both cabs in to the two speaker outs on the rock crusher. This is how I use it after talking to Rivera about it, just call them or shoot them an email to be sure. I have a 8ohm silent sister and a 8ohm k212 plugged into it.

I do not know what the rockcrusher is, but i can tell you that there is a variable called impedance reflection. You do not send impedance as an output, impedance is resistance in the imaginary plane as it is an opposition to current flow based on phase correlation.

You cannot do what you want to do because the rock-crusher will not see the intended impedance of 8ohms on the secondary of the output transformer. The amplifier would be happy to run with this setup however the rock-crusher would not. I do not know or understand what the rock-crusher is, but it specifically says not to have a 4 ohm secondary connection and that is exactly what you would be doing in order to run two 8 ohm sources in parallel on the secondary of the output transformer of the amplifier.

In simpler terms no you cannot. Amplifier would be fine, but the rock-crusher was not designed or intended to be ran in parallel with another reactive device where impedance reflection comes into play.

Either run it attenuating both or do not run it at all and you're good.

 

[steve_k]

Okay, so this is my crazy onstage connection (or at least the idea that I have). High gain amp going to the RIVERA Silent Sister ISO cab (to feed the FOH guy a nice signal). Then for my "stage monitor" a 212 cab (celestian v30's) and in-between that a RIVERA Rockcrusher. My amp is set for the "sweet spot" which means master and channel gain close to 12 o'clock (stupid loud under normal circumstances, but oh does it sound amazing!).

So, my question is: will I damage any of my gear if I have it set up this way (don't know much about speaker ohm and load impedence

4 ohm out from the amp (parallel) = 1) to RIVERA Silent Sister (8ohm cabinet). 2) to RIVERA Rockcrusher set to 8ohm to a 212 cabinet (8 ohm mono).

I thought that if you run in parallel it's the ohm divided by the number of cabinets: 8/2 so 4 ohm in my case. Does this mean it's sending 4 ohm load to EACH CABINET. The reason I'm asking is because the Rockcrusher's manual says: "DO NOT USE THE ROCKCRUSHER ON AMPLIFIERS THAT ARE HARDWIRED FOR 2 OR 4 OHMS, OR DO NOT HAVE 8 OR 16 OHM OUTPUT IMPEDANCE CAPABILITY. DO NOT USE THE ROCKCRUSHER WITH ANY SPEAKER LOAD LOWER THAN 8 OHMS IMPEDANCE."

If anyone can help me that would be awesome!

PJ

PS: Or I can just get an Axe FX lol

I think Matt is right in his rationalization with the impedance reflecting. The attenuator is bouncing the parallel signal back and you really don't know what your head is seeing.

However, why don't you just run through the Silent Sister to your mixer for the FOH, then send a line level signal back through an AUX OUT to your passive stage monitors for the band or to an active FR monitor for some stage noise where the volume can be controlled with the AUX level?

Also, doesn't the Rock Crusher have a line out thru signal that will send an unattenuated signal to the FOH, yet attenuate the signal to your 8 ohm cab?

Steve

 

[pjrake]

The rock crusher impedance doesn't have to match on the front and back. The input needs to be 8 or 16 from your amp but then just plug both speaker cabs into the rock crusher which will handle a 4 ohm speaker load. What it won't do is function as a 4ohm load. Set the amp to 8 and the rock crusher to 8 then plug both cabs in to the two speaker outs on the rock crusher. This is how I use it after talking to Rivera about it, just call them or shoot them an email to be sure. I have a 8ohm silent sister and a 8ohm k212 plugged into it.

I do not know what the rockcrusher is, but i can tell you that there is a variable called impedance reflection. You do not send impedance as an output, impedance is resistance in the imaginary plane as it is an opposition to current flow based on phase correlation.

You cannot do what you want to do because the rock-crusher will not see the intended impedance of 8ohms on the secondary of the output transformer. The amplifier would be happy to run with this setup however the rock-crusher would not. I do not know or understand what the rock-crusher is, but it specifically says not to have a 4 ohm secondary connection and that is exactly what you would be doing in order to run two 8 ohm sources in parallel on the secondary of the output transformer of the amplifier.

In simpler terms no you cannot. Amplifier would be fine, but the rock-crusher was not designed or intended to be ran in parallel with another reactive device where impedance reflection comes into play.

Either run it attenuating both or do not run it at all and you're good.

Thanks, dude. I appreciate your help.

It's one of those cases where I know how to drive a car, but don't know how the engine works. Maybe it's time I learn how that damn engine works!

PJ

 

[pjrake]

Okay, so this is my crazy onstage connection (or at least the idea that I have). High gain amp going to the RIVERA Silent Sister ISO cab (to feed the FOH guy a nice signal). Then for my "stage monitor" a 212 cab (celestian v30's) and in-between that a RIVERA Rockcrusher. My amp is set for the "sweet spot" which means master and channel gain close to 12 o'clock (stupid loud under normal circumstances, but oh does it sound amazing!).

So, my question is: will I damage any of my gear if I have it set up this way (don't know much about speaker ohm and load impedence

4 ohm out from the amp (parallel) = 1) to RIVERA Silent Sister (8ohm cabinet). 2) to RIVERA Rockcrusher set to 8ohm to a 212 cabinet (8 ohm mono).

I thought that if you run in parallel it's the ohm divided by the number of cabinets: 8/2 so 4 ohm in my case. Does this mean it's sending 4 ohm load to EACH CABINET. The reason I'm asking is because the Rockcrusher's manual says: "DO NOT USE THE ROCKCRUSHER ON AMPLIFIERS THAT ARE HARDWIRED FOR 2 OR 4 OHMS, OR DO NOT HAVE 8 OR 16 OHM OUTPUT IMPEDANCE CAPABILITY. DO NOT USE THE ROCKCRUSHER WITH ANY SPEAKER LOAD LOWER THAN 8 OHMS IMPEDANCE."

If anyone can help me that would be awesome!

PJ

PS: Or I can just get an Axe FX lol

I think Matt is right in his rationalization with the impedance reflecting. The attenuator is bouncing the parallel signal back and you really don't know what your head is seeing.

However, why don't you just run through the Silent Sister to your mixer for the FOH, then send a line level signal back through an AUX OUT to your passive stage monitors for the band or to an active FR monitor for some stage noise where the volume can be controlled with the AUX level?

Also, doesn't the Rock Crusher have a line out thru signal that will send an unattenuated signal to the FOH, yet attenuate the signal to your 8 ohm cab?

Steve

I thought of that, but trying to avoid getting the soundguy involved. Some don't want to be bothered. What I can do is use the second mic on the Silent Sister and run that to me, and get one of those Atomic FR powered cabs (either a 212 or wedge). Would probably need to get a mic preamp if I wanna go that route. Damn, more stuff to buy! ARGHHHH

PJ