The HOMster! (or How I Learned How to Fix a Horn)

[Patrick Bateman]

Originally Posted by panomaniac

I'm with you on that! Getting most of the midrange into a good horn or waveguide lends great results. I have had that "hey! who are all those back-up singers?" moment. =) Where were they hiding before?

Nice work! Amazing for a car. (my car has 6 speakers - only 1 works)

In some ways it reminds me of the difference between a solid state amp and a single ended triode. The triode has a way of extracting every last ounce of details that's mesmerizing.

After I finish the car I believe I am going to resurrect my home theater unity project. I think that the things that make the Unity so special could be well suited to a surround sound system, where timing is so important. At the very least, the extra intelligibility will improve dialog in movies.

And anyways, I got the Summas upstairs, and my home theater speakers are from Costco. I *gotta* rectify that soon

[gedlee]

Originally Posted by Patrick Bateman

In some ways it reminds me of the difference between a solid state amp and a single ended triode. The triode has a way of extracting every last ounce of details that's mesmerizing.

I got the Summas upstairs, and my home theater speakers are from Costco. I *gotta* rectify that soon

Just buy three Abbeys and some Harpers and you'll be all set Oh yea and some subs.

In my mind its not tubes versus transitors, its crossover versus non. Virtually all transitor amps are AB and thats a recipe for disaster at low level zero crossings which is exactly where things are the most audible.

[winslow]

Dr. Geddes, just wanted to say I appreciate you "dropping some knowledge" where and there on the internet. Just my little experience experimenting with some of your ideas and suggestions has really convinced me that you are preaching the truth. While I don't own any of your products at the current time, I know my next home system will have your products in it.

[winslow]

Are you referring to crossover distortion? And if so, would you say that high sensitivity speakers make such things more audible? Maybe could be some form of harshness?

Originally Posted by gedlee

In my mind its not tubes versus transitors, its crossover versus non. Virtually all transitor amps are AB and thats a recipe for disaster at low level zero crossings which is exactly where things are the most audible.

[gedlee]

Originally Posted by winslow

Dr. Geddes, just wanted to say I appreciate you "dropping some knowledge" where and there on the internet. Just my little experience experimenting with some of your ideas and suggestions has really convinced me that you are preaching the truth. While I don't own any of your products at the current time, I know my next home system will have your products in it.

Thank you very much. Its been a life long pursuit to find the truth in audio and while I may not have all the answers, I think that ones that I do have are pretty well founded in reality.

Originally Posted by winslow

Are you referring to crossover distortion? And if so, would you say that high sensitivity speakers make such things more audible? Maybe could be some form of harshness?

Yes, crossover distortion, and yes I do believe that high efficiency speakers will accentuate this problem. You are very perceptive. I believe that what audiophiles call "lack of detail" could well be related to this since "detail" means low level signals and the lower the level of the signal the more it is affected by crossover distortion. In my studies of the audibility of distortion crossover distortion was, by far, the most audible and insidious. So much so that it is all I look for in an amp. Curiuosly, the way amps are measured and rated this problem won't show up.

[konut]

Originally Posted by gedlee

In my studies of the audibility of distortion crossover distortion was, by far, the most audible and insidious. So much so that it is all I look for in an amp. Curiuosly, the way amps are measured and rated this problem won't show up.

How would one measure crossover distortion? Great thread!, BTW.

[gedlee]

Originally Posted by konut

How would one measure crossover distortion? Great thread!, BTW.

If you look at the spectrun of a 1kHz tone as the signal level is reduced the harmonics should fall with level or stay the same. If they grow, or even worse, the number of orders increases (which is very common) as the signal is reduced then there is crossover distortion and you should throw the amp away. You can't look at THD VS level, because at low signal levels all you are measureing is noise. In a good amp, like I have, the harmonics of the signal should disappear into the noise floor as the signal level is reduced. There are actually ways to measure this using a sychonous signal that will measure below the amps noise floor. This is very revealing.

[JLH]

Originally Posted by gedlee

In a good amp, like I have, the harmonics of the signal should disappear into the noise floor as the signal level is reduced.

Which amplifier are you using? It is very hard to find a good amplifier with all the marketing nonsense we see today.

Rgs, JLH

[winslow]

Interesting. The only way I knew to get around the problem of crossover distortion and high efficiency speakers was to use a class A amp.

[gedlee]

Originally Posted by JLH

Which amplifier are you using? It is very hard to find a good amplifier with all the marketing nonsense we see today.

Rgs, JLH

Originally Posted by winslow

Interesting. The only way I knew to get around the problem of crossover distortion and high efficiency speakers was to use a class A amp.

Not at all, there are very good solid state class AB amps out there. The best one that I have tested is my Pioneer receiver, which uses chip amps. Chip amps are inherently better off in class AB because the component matching is ideal (same substrate). My Pioneer has only a second harmonic all the way down into the noise floor, no higher orders at all. NOT SO for most receivers. And you are correct, the spec sheets and advertising are totally meaningless when it comes to audible quality. Unless you measure it yourself you have no way of knowing if its any good.