Seeking thoughts on Apogee Caliber Ribbon speakers

Dear Br3098, it is obvious that your knowledge of ribbon speakers is far above mine. With that in mind I'd like to ask you a question. At moderate volumes and above I will get substantial "breakup" when bass is anything but flat. I have examined the woofer and there is nothing loose. The ribbon seems to be as taught as a person would want it to be (without any definite knowledge of that). I am using a 63 watt rms amp for the woofer and the same for the mid/upper. I cannot compare the two speakers just yet. I don't want to do anything to the second one before I have had a chance to remove it from the case and check for any problems. Just a little anxious here. The amp I am using I am assuming is the problem. I don't think it can cope with a 3 ohm load. It a Phast 8 channel x 63 watt unit. Might you have any thoughts on this situation? Ribbon Newby

Bababondoman,

OK, I can answer you now that my swelled head had shrink back down to it's former insignificance.

You are almost certainly correct; your 65Wpc amp is not adequate to power the Apogee Caliper speakers. I would advise you to stop using these speakers with this amp IMMEDIATELY as you run a real risk of damaging both the amp and the speakers, if you haven't already done so.

From your last two posts I assume that you are attempting to use some form of horizontal bi-amping (seperate amps for the ribbon tweeter and the woofer panel), possibly with a multi-channel amp. Is this correct? From personal experience, I would avoid attempting to horizontal bi-amp unless you have a serious fascination with tweaking or repairing electronics. Vertical bi-amp (separate amps or monoblocks for each speaker) yes, certainly; but you will need to provide adequate power at very low loads.

I would recommend a MINIMUM of 125Wpc at <4 Ohms. 200W-250W or more would be better if your room is large (which I assume it is for these speakers) and if you intend to play large orchestral music. I would suggest the following as reasonably priced options:
1. McCormack DNA-1, 2, 125, 225 - remember you will need two if you are going to bi-amp (bridged mode)
2. Krell KAV-250a (not the /3 model) or KAV-500. (you will want two of the 250)
3- TAD Hibachi amp - monoblock pair

My personal choice would be one of the McCormack amps, preferebly rebuilt by Steve McCormack's SMC Audio. There are many amps that will work and you will undoubtedly receive other good suggestions.

Since I did not know if the 65 wpc 8 channel amp I was using was capable of 3-4 ohms without biting the dust I chose to take that chance. I had a mono signal feeding two of the channels and the outputs for low and high of each 65watts going to the Caliber. On a ribbon speaker, without any voice coil to bottom out I was under the impression that occasional distortion, while testing, would do no harm to the ribbons as long as the "excursion" was not obviously excessive. It wasn't. Perhaps you are concerned about the crossover networks? However, I AM going to take your advice and shelf the amp and try another amp that I have somewhere. It is rated at 185 watts at 4 ohms. THAT ought to do the trick I imagine. Since I have never listened to ribbon speakers before I don't know what to expect other than the reviews I've read. I will admit that I like a LOT of bass due to my love of pipe organ music. I do know that these speakers will not have a great deal of spl at low frequencies. I'll try the 185 wpc amp and report back with my observations. Thanks again for taking your time and giving me advice. :)

You need a very solid 200/channel amp that can pour power into difficult loads.

Everyone....I hooked up a stereo amplifier that I mentioned that is rated at 185 wpc rms each channel operating. One channel for speaker low and one channel for speaker hi. 370 watts to the speaker. Everyone was completely correct. I DID need far more power. Everything sounded 95% better! Also improved was the muddiness that was heard in the bass when volume fairly high and the bass boosted. It now occurs at a much higher volume level only. Maybe it STILL requires more power!! I have the power company on the way out here to give and estimate on three phase power to run the new amps. ;)