Audiophile Series seven π loudspeaker

Where you have no corners, I might suggest that you use an Eminence Magnum driver in a suitable enclosure below the midrange and tweeter shown above. I have plans for those too, if you're interested.

One advantage of corner loading is that it forces a radiation angle of 90º. You can see in the photo above that the midrange and tweeter also have this pattern, so this reduces reflections. When the woofer is placed in or near the corners, room modes are equally charged. Also, since all sound sources share the same 90º radiation pattern, the reverberent field has an equal distribution of frequencies and sound is uniform and natural throughout the room. This not only helps make the "sweet spot" larger, but it also makes the sound more balanced within the sweet spot.

In the past you have recommended low Zmax woofers for single ended tube amps. In this case do you feel that the benifits high magnet strengh of the Magnum outweigh the problems with high Zmax?

TIA

Dave

I think the ETF presentation by Lynn may shed some light on this.

http://www.nutshellhifi.com/library/ETF.html

Looking at the output loop of a conventional SE amplifier and combining this with hi vs low Zmax you could assume that the 'longer' path to ground with a larger cap between SE xformer and earth will affect performance more than let's say the parafeed arrangement with s small cap to ground handles the AC part of the signal....maybe why parafeed seem less sensitive to speakers than conventional SE. This of course not heard by me, only based on comment from the board.

The ETF presentation great for understanding the different topologies anyway...a must read???

PS Wayne. Planning the build of the Stage4, should happen in 2 weeks time...home alone one weekend:) no distractions.

• ETF

What we're dealing with here is essentially a voltage divider with a reactive load that varies with frequency. If the output circuit is a constant voltage source, it isn't as sensitive to reactive loads as a constant current source. Some SET amps have high output impedance, which makes the amp act like a current source. As a result, load impedance fluxuations cause corresponding response fluxuations.

Here are some other good links:

• Highly Reactive Loads and SET Amplifiers
  
• Effects Of Source Impedance on Loudspeakers
  
• Variable Amplifier Impedance
  
• Feedback and fidelity
  
• What is Negative Feedback?

Naturally, the seven π-18 with it's 18" woofer delivers deeper response than the seven π with a 15" driver. It has a larger driver in a larger box. The crossover point to the midhorn is very low, so midbass and midrange performance is virtually identical. The eight π is a different configuration entirely, and really no comparison should be made. It is designed for a different price point.

Dave

Thanks for the links. I'll check them out tonight.

Dave