Quad 2805 reliablity? Distance from wall needed?

I have used Quads off and on since the early 60s and was a dealer for 20 years; now have apogees. The whole distance question boils down to this: all bipolar radiators produce equal sound pressure backward and forward. If you are too close to the back wall the back wave will be reflected against the rear of the speaker and lessen bass excursion. How close is too close? Judge for yourself. All rooms are different and everyone hears different things. Try them closer and farther away. I would not worry about it. As Macdadtexas says , most Quads are damaged by being grossly overdriven. If you accept their limitations in level they are hard to match. If I were using them today I would use a REL sub driven off the amp outputs as I do with my Spendors. What you have to decide is weather you listen at a level that is within their range. I once sold a pair of 63s to someone against my better judgement. I had a nelson reed system that would play VERY loud and I once measured the playback level he was listening to at 108 DB. Of course he blew them up several times and blamed it on his amp. That is the only pair I ever had trouble with.

The radiated sound from the rear of the speaker will bounce off the rear wall and reach your ears after the sound from the front of the speaker. If the time lag between front and rear radiations is short (because the speaker is near the rear wall), you will "hear" (process) the sound as smeared. If the speaker is optimally 5.5 feet from the rear wall (or slightly further away) you will hear the difference as room or hall ambience, a pleasing complex of sounds.

I have owned my 2805's for about 3 years without any reliability problems at all. But after reading some of the posts here, on AA, and other sources about the reliability issues with the new Quads I got concerned and called the importer and QS&D (who are the only CERTIFIED Quad repair facility in the US). I got the same explanation from both sources.

There are no reliability issues with the new Quads. They are just as reliable, if not more, than the 63's. The typicaly problem is, as others have mentioned, listeners just turn them up too loud or they use over powered or under power amps with them.

One of the problems for people who go from dynamic driver speakers to the Quads is that they turn the Quads up too loud because they are expecting to hear a level of distortion that you just don't ever get with Quads. Turning them up too loud causes them to be overdriven which activates a "clamping circuit" and shuts down or reduces output of the speaker. Over time, overdriving them can cause pin holes in the panels and this eventually results in the panels failing or tearing.

If you understand the limitations of Quads and drive them with an appropriate amp, there are no reliability issues and you'll get many years of enjoyment from them. They are the best sounding speaker I have ever owned and will be long term keepers. I have actually found that I listen at lower levels with Quads than any previous speaker, because you hear all the musical detail even at low levels. I typically listen at 80db, as measured at my listening seat. With previous speakers I listened louder to get the same experience of the music.

Regarding distance from the front wall, the importer said they can be as close as 3 feet but your room and listening preferences will determine best placement. Mine are about 4 feet out and they sound very balanced, and I sit about 9 feet from the front of each speaker.

Dave

Thanks everyone for all of those comprehensive answers.
I appreciate it.

This is not a professional response but I placed some panels behind my 63's that seem to radiate the back wave and make for very good sound with them around 2 feet from the back wall.