Educate me on amps, my Vistas and Bi Amping. Vista/Fresco/Dual Depth i

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Mobs

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Hello all!

I recently changed my AVR (Denon 4308) for new model (Onkyo 5009) to use with my Sherbourn 7-2100 amp.

I used the 7 channels on the amp to power my Center, Surrounds and Bi-Amp my Vistas (vertical as per ML's description). My amp is rated @ 200 wpc @ 8ohms and 300 wpc @ 4 ohms. You can also bridge two channels of the amp to run 400 wpc @ 8 ohms, but they do not want you to bridge and run at 4 ohms.

My amp has something called an LDS switch. Basically, when your speakers are connected it will tell you if there is a problem with the speaker connection to that particular channel by illuminating a LED a particular color. Green is a good connection, Orange is an open circuit or a speaker of high impedance is being used, and Red means a short circuit or speaker impedance is too low.

Well, I have never had any Red indicators. YAY! But I do have Orange.

Now, if I haven't lost you yet, this is where it gets interesting (for me at least).

The Orange LED only shows on the connections for my Fresco (center) and the Panels of the Vista.

Well, this got me thinking (bad combination sometimes) about the following scenarios...

1. In a Bi-Amp scenario with the woofer and panel having their own independent connections to individual channels on my amp, the panel would be pulling more power because of the impedance.
2. In a single wire scenario using the Vista's jumpers and only one channel driving the woofer and panel the would both be pulling the same amount of power.

Am I off base with this thought?

I took this a step further. My amp can bridge channels, just not 4 ohms or less. I have confirmed this as the amp will power off immediately when trying to bridge two channels to a single wire/jumper connection to the Vista.

But, I can bridge two channels and power the woofer and use a single channel to power the panel. When I did this the experiment the bass really came to life. I felt the speaker sounded more like a Vantage with its powered woofer after this connection. I did not get the feeling that the low end over-powered the panel, but it was more pronounced.

Sadly, I do not have any way to adjust the gain on the channels of my amp.

Obviously ML thought about this long before I, but it seems to be that "Vertical Bi-Amping" as per their definition is not a good solution with the Vistas. I think you would be better served to single wire or "Horizontal Bi-Amping" would be a better solution.

All of this rambling is leading up to the fact that I took delivery of a second Depth i today which I cannot wait to get home and set up and run Audyssey Multi XT32 with dual subs to see that outcome.

I will probably keep crossing over the Vista's at the 70 mark.

Opinions on my thoughts, or lack there of? Am I about to blow up my house?
 
Well, I have never had any Red indicators. YAY! But I do have Orange.
The Orange LED only shows on the connections for my Fresco (center) and the Panels of the Vista.
Congrats!! You're the first one to bring this issue of high-impedance to (orange) light! (pun intended). I've been posting for years that the Logan panels have wild swings from 30 ohms at the low frequency range to ~1 ohms at 20khz. Most people get fixated on the 1-ohm specification, but fail to consider the high impedance at the other end of the spectrum. I think what your amplifier is trying to tell you is just that it detects a large impedance swing when you hooked up to the Vista panel. Check with Sherbourn to see whether this will be a problem with your amplifier.


But, I can bridge two channels and power the woofer and use a single channel to power the panel. When I did this the experiment the bass really came to life. I felt the speaker sounded more like a Vantage with its powered woofer after this connection. I did not get the feeling that the low end over-powered the panel, but it was more pronounced.
This is to be expected as long as your amplifier is up to the task.

Sadly, I do not have any way to adjust the gain on the channels of my amp.
Do you need to adjust gains on the channels of your amp? You can do it cheaply by looking up "Harrison Labs line level attenuator" from partsexpress.com.
 
With bridging, your putting double the voltage across the speaker compared to non-bridged for the same signal input; the bridged configuration is giving an extra 3dB gain. So you'd need to add a 3dB pad (attenuator) to the input of the bridged amps to maintain the balance between the woofer and the panel.

Interesting thought about the impedance differences between the woofer and panel sections and if bi-amping will result in more or less relative volume to either one. I suspect that a good amp will produce the same sound level output from the panel whether the woofer section is connected or not. Although if the woofer section is presenting an additional impedance load above the 450Hz crossover point, then yes, the panel would put out more sound at those frequencies when bi-amped. So things may sound a little different at frequencies around the crossover point when comparing a single amp driving the Vista to bi-amping. Would be interesting to see if frequency response measurements show any difference.
 
Double voltage means +6dB so your frequency response is all over the place if only woofer amp is bridged when using similar amp for panel. Amp driving panel should never be bridged as the load it presents. If your amp detects open circuit it's because panel crossover is connected via capacitor, no big deal.
 
Hi I am going through the same problem with my Sherbourn I just got. I am getting the orange on the stage center speaker. Did you contack Sherbourn and find out anything. Any comment would be apprecieated. thanks
 

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