I just bought a used set of Concerta F12's. Two categories of questions emerge: Room arrangement and amplifier arrangement. If you want to look at the amp question first, it's way at the bottom.
ROOM:
My current system is grossly suboptimal, and was unchangeable for a lot of reasons. But these new towers certainly aren't going to go where my Advents are currently resting, so stuff's gonna hafta change anyway. Here's an (old--electronics have changed) picture looking towards the stereo cabinet, showing the sloped ceiling and the current Advents.
As you may surmise, the listening chair is the camera location, and the tuba practice area is in front of the stereo cabinet. I'm thinking about flipping this around. so that the new speakers will be to my left and the listening position will be to the right of the picture. Here's a plan view of my proposed arrangement (these sketches are accurately scaled, new speakers are shown in red):
The picture looks at the top of those stairs from what is shown as the tuba practice chair next to the piano.
The towers would be 7ish feet apart (could easily be 6 and still fit), and 7-8 feet from the listeners, and still have some adjustment room away from the wall behind the speakers. The black blobs are tubas in gig bags (there are more under the piano). The black rectangles at upper left are the stereo cabinets that you see in the picture. Yes, I know it's a problem for the listening chair to back against a wall, though that wall is only a partial wall next to a staircase.
The vertical situation is key to understanding this space. In the plan view, it looks constrained, but the ceiling slopes up from the window bank at the bottom to a peak above a second-floor loft. Here's a section view to show that:
This is obviously a difficult space in some ways. This is the only room available for serious listening, even though it's not a good spot simply because of how it opens into the rest of the house. But when I listen, my wife retreats to the bedroom instead of watching television in the large adjacent room. Even though the distances in the listening area are modest, the room opens into quite a large volume, but with few places to create resonant modes. The only strong resonant mode is between the far wall in the section (against which the Advents were placed) and the opposite wall. At 20 feet, this resonates in the upper 50's. and you can see that in the waterfall below (made using the Advents). But it does not ring that severely at all. I'm just a beginner with REW, of course, though I do have a calibrated microphone piped through a PreSonus interface that I nulled using a loopback test. The mic was in the old listening position, but ringing bass room modes do not appear to my ears as I move around, and I'm rather practiced at hearing those frequencies.
The advantage to the sloped ceiling is that I don't think I'll have much of a problem with early reflections from the ceiling. The mirror point is directly above the back edge of the proposed speaker location. The floor is carpeted with an area rug on top of the carpet. This has been a good room for tuba practice, and practicing tuba with a flat 8-foot ceiling is...unpleasant.
Maybe there is an issue with asymmetry with the side walls. Obviously, I'm closer to the listener's right wall than to the left wall. But I don't think that will be that much of an issue, either. A chunk of the first reflection from the right wall is actually an opening, and at listening height, the left wall is covered by a grand piano, and the only reflection surface there is the short section of the piano's bent side. I can park a tuba at that spot to act as a diffuser.
The biggest issue will be with the partial wall behind the listening chair. That may be the one place where I can add some treatment, though it will not receive spousal approval if it covers the stair railing (which it wouldn't need to do anyway).
Before I disrupt the house, am I on the right track? Validation is what I seek.
(Relocating the piano is not an option.)
AMPLIFIERS:
I am currently powering two pairs of Advents using two B&K Reference 125.2 amplifiers. The amps are rated at 185 wpc into 4 ohms, and claim to be able to supply 30 amps peak-peak. I am able to run the Advents to music peaks (trumpet playing) of, say, 105-108 dB SPL, C-weighted. This is a use case for me, for when I play tuba with recordings. (If I do that, I will move my practice chair out into the middle of the room with the new arrangement). Loud listening for me, though is like it is for everyone else: In the low 90's. One reason I was attracted to these speakers is that everything I read suggests playing music at 108 dB SPL won't be a problem for them.
I like the notion of big amps loafing along, and I recognize that the F12's will probably get very loud with just one amp running in stereo. But I have two, so there are options.
Revel offers two bi-amping strategies, which they call "vertical" and "horizontal". In vertical biamping, one uses Amp A for the right speaker, and Amp B for the left speaker. The right channel of Amp A is wired to the mid/tweeter speaker terminal, and the left channel of Amp A is wired to the woofers. Amp B is wired similarly to the left speaker. They warn that both amps must be identical, which these are. They do not suggest any need for external crossovers, so I gather that the filtering for each driver is appropriately wired to stay in the circuit even in this arrangement. This is a way to use a stereo amp that has no bridging capability in a dual-mono configuration.
The horizontal arrangement is the more conventional bi-amping arrangement that I've always read about. Amp A drives right and left speaker woofers, and Amp B drives right and left speaker mids and tweeters. They require that both amps have the same gain structure for this to work, which these, of course, do.
So, which might be better? Separating the amps between left and right, or separating the amps between frequency band? Or will it not matter?
I do not use computer-based DSP--I frequently listen to analog sources or to the analog outputs of CD players. I do, though, have two very good 20-bit digital parametric equalizers from Yamaha's 90's-era commercial line. I'm currently running one in the processor loop of my Adcom preamp.
In any case, each speaker will be driven by two amp channels rated at 125 watts into 8 ohms, and 185 into 4 ohms. That exceeds the rating of the speaker (200 watts, though they don't say if that's the 8-ohm rated power or the actual power at the nominally 6-ohm speaker), but I don't have children and I know how to behave myself. I think the volume would become unlistenably loud before reaching the danger point.
Advice welcome!
Rick "thank you" Denney
ROOM:
My current system is grossly suboptimal, and was unchangeable for a lot of reasons. But these new towers certainly aren't going to go where my Advents are currently resting, so stuff's gonna hafta change anyway. Here's an (old--electronics have changed) picture looking towards the stereo cabinet, showing the sloped ceiling and the current Advents.
As you may surmise, the listening chair is the camera location, and the tuba practice area is in front of the stereo cabinet. I'm thinking about flipping this around. so that the new speakers will be to my left and the listening position will be to the right of the picture. Here's a plan view of my proposed arrangement (these sketches are accurately scaled, new speakers are shown in red):
The picture looks at the top of those stairs from what is shown as the tuba practice chair next to the piano.
The towers would be 7ish feet apart (could easily be 6 and still fit), and 7-8 feet from the listeners, and still have some adjustment room away from the wall behind the speakers. The black blobs are tubas in gig bags (there are more under the piano). The black rectangles at upper left are the stereo cabinets that you see in the picture. Yes, I know it's a problem for the listening chair to back against a wall, though that wall is only a partial wall next to a staircase.
The vertical situation is key to understanding this space. In the plan view, it looks constrained, but the ceiling slopes up from the window bank at the bottom to a peak above a second-floor loft. Here's a section view to show that:
This is obviously a difficult space in some ways. This is the only room available for serious listening, even though it's not a good spot simply because of how it opens into the rest of the house. But when I listen, my wife retreats to the bedroom instead of watching television in the large adjacent room. Even though the distances in the listening area are modest, the room opens into quite a large volume, but with few places to create resonant modes. The only strong resonant mode is between the far wall in the section (against which the Advents were placed) and the opposite wall. At 20 feet, this resonates in the upper 50's. and you can see that in the waterfall below (made using the Advents). But it does not ring that severely at all. I'm just a beginner with REW, of course, though I do have a calibrated microphone piped through a PreSonus interface that I nulled using a loopback test. The mic was in the old listening position, but ringing bass room modes do not appear to my ears as I move around, and I'm rather practiced at hearing those frequencies.
The advantage to the sloped ceiling is that I don't think I'll have much of a problem with early reflections from the ceiling. The mirror point is directly above the back edge of the proposed speaker location. The floor is carpeted with an area rug on top of the carpet. This has been a good room for tuba practice, and practicing tuba with a flat 8-foot ceiling is...unpleasant.
Maybe there is an issue with asymmetry with the side walls. Obviously, I'm closer to the listener's right wall than to the left wall. But I don't think that will be that much of an issue, either. A chunk of the first reflection from the right wall is actually an opening, and at listening height, the left wall is covered by a grand piano, and the only reflection surface there is the short section of the piano's bent side. I can park a tuba at that spot to act as a diffuser.
The biggest issue will be with the partial wall behind the listening chair. That may be the one place where I can add some treatment, though it will not receive spousal approval if it covers the stair railing (which it wouldn't need to do anyway).
Before I disrupt the house, am I on the right track? Validation is what I seek.
(Relocating the piano is not an option.)
AMPLIFIERS:
I am currently powering two pairs of Advents using two B&K Reference 125.2 amplifiers. The amps are rated at 185 wpc into 4 ohms, and claim to be able to supply 30 amps peak-peak. I am able to run the Advents to music peaks (trumpet playing) of, say, 105-108 dB SPL, C-weighted. This is a use case for me, for when I play tuba with recordings. (If I do that, I will move my practice chair out into the middle of the room with the new arrangement). Loud listening for me, though is like it is for everyone else: In the low 90's. One reason I was attracted to these speakers is that everything I read suggests playing music at 108 dB SPL won't be a problem for them.
I like the notion of big amps loafing along, and I recognize that the F12's will probably get very loud with just one amp running in stereo. But I have two, so there are options.
Revel offers two bi-amping strategies, which they call "vertical" and "horizontal". In vertical biamping, one uses Amp A for the right speaker, and Amp B for the left speaker. The right channel of Amp A is wired to the mid/tweeter speaker terminal, and the left channel of Amp A is wired to the woofers. Amp B is wired similarly to the left speaker. They warn that both amps must be identical, which these are. They do not suggest any need for external crossovers, so I gather that the filtering for each driver is appropriately wired to stay in the circuit even in this arrangement. This is a way to use a stereo amp that has no bridging capability in a dual-mono configuration.
The horizontal arrangement is the more conventional bi-amping arrangement that I've always read about. Amp A drives right and left speaker woofers, and Amp B drives right and left speaker mids and tweeters. They require that both amps have the same gain structure for this to work, which these, of course, do.
So, which might be better? Separating the amps between left and right, or separating the amps between frequency band? Or will it not matter?
I do not use computer-based DSP--I frequently listen to analog sources or to the analog outputs of CD players. I do, though, have two very good 20-bit digital parametric equalizers from Yamaha's 90's-era commercial line. I'm currently running one in the processor loop of my Adcom preamp.
In any case, each speaker will be driven by two amp channels rated at 125 watts into 8 ohms, and 185 into 4 ohms. That exceeds the rating of the speaker (200 watts, though they don't say if that's the 8-ohm rated power or the actual power at the nominally 6-ohm speaker), but I don't have children and I know how to behave myself. I think the volume would become unlistenably loud before reaching the danger point.
Advice welcome!
Rick "thank you" Denney