Soundstage

[Clipped and Shorn]

Using my ear (and perhaps the unique characteristics of the LP I happen to be playing at the time) I was able, just now. to tweak the delay functions on my electronic crossover for the first time. There is one for the the bass and one for the mid-range of both channels. I was never quite able to hear any difference before and I was led to believe it required special test equipment to make the adjustment. I think maybe my hearing has evolved a bit and I think the new preamp may have also helped.

What this delay function does in effect is to help line up all the drivers so they sonically appear to emanate from the same plane. In other words, it compensates for the fact that the horn drivers sit further back in the cabinets than the other two 15' cone drivers . I was able in effect to "push back" the plane of the two 15" cone drivers so they appear to come from the same plane as the horn drivers.

The effect on the soundstage clarity was rather dramatic. It is an example of the whole being greater than just the sum of the parts. It suddenly kicked into place in a big way and it has made a dramatic difference in soundstage and presence.

I am using a Rane 3-way stereo (4 way mono) electronic crossover because it has these nice options and all that other good stuff (Linkwitz Riley....etc.) . The bass and mid range functions control the two 15" (Altec 416b and 515c), the high section controlling the 511b Horn with Altec 802g driver (no delay function for the high section).

This small tweak made for a big breakthrough in soundstage quality, at least to my ears.

They don't worry about this with Cornwalls apparently, but the Altec 511b horn is a bit longer and perhaps makes more of a difference, at least it does in my 3 -(4)- way cabinets with 4' vertical difference between bass driver and horn. This electronic crossover helps to pull it all together.

This whole eccentric approach works for me and it is sounding pretty good these days.

C&S

[maxg]

Is this something the standard crossover of any speaker is supposed to do anyway? I thought that was one of its primary functions as many speakers have drivers that vary in their absolute distance from the listening position - not just horns.

I would certainly expect the Xover on the Cornwall to have taken this into account when the thing was originally designed. Of course changing the Xover for either a new passive design or an active design requires introduction of delays which it seems you have discovered.

I suppose that varying the delay times is one way to affect the voicing of your speakers - and you could probably introduce some startling effects if you are of a mind to.

Anyway - congrats on your discovery.

[Clipped and Shorn]

I am not sure if that is something that a passive crossover does. Maybe some of the experts here can elucidate.

C&S

[Colin]

interesting, any way of knowing how much delay, my DEQ2596 can add delay, but I have not gotten around to trying it yet-

you have got a very interesting system there, what would you rate as the most valuable component? then what after that? what are the most valuable parts of your system?

[ben.]

Rough figure is 1ms per foot. I don't think passive crossovers are capable of this, but may play with relative phase? I'm out my depth with that...

[maxg]

Where is Dean when you need him?

[Clipped and Shorn]

I did this adjustment strictly by ear until it sounded best. Each dial for the delay has a scale of 10 (min to max ). I have them all set at around 7. Guess I could dig up the manual and try to understand what the heck I did there. In other words I put a delay of "7" on each of the 15" drivers which are at least 16" in front of the horn drivers. This setting maximized the desirable effect that I could notice with soundstage and "presence". I am not saying this makes any theoretical sense regarding the precise numbers involved in the actual physics, I just tweaked until everything sounded good, better than before. The general concept does make sense to me.

C&S

[Deang]

You can EQ with a passive, but you can't do time delay.

[Clipped and Shorn]

I struggled for quite awhile with the Cornwalls here. Went from SS to tubes. Currently have an Eico hf-81 on the Cornwalls but was never really happy with them for large ensemble sound. They are best for small group jazz with tenor sax.

Mark Deneen had a system ( a few years back) he showed me which is the basis and inspiration for mine. He posted his progress while constructing his cabinets right here on the forum. Being a fellow Californian I eventually met him and heard his system. His system sounded real good. He had it bi-amped. Bigger power going to the bass and nice triode tubes for the mids. He introduced me to the accessible idea of diy speaker cabinet + electronic crossover. I liked how good his system sounded even at higher volumes. It way outperformed anything I could get with the Cornwalls at that time. I decided to go that route. No regrets. Even today, I would still not have a good place to incorporate Khorns, so I was able to shape my diy cabinets to exactly fit the available space in the living room. I enjoy that I made these monsters myself....kind of like a custom hot rod speaker cab.

I expanded on his idea and made mine a 4-way system. The tweeter and horn use a passive crossover, everything else is controlled by the electronic crossover. Mark helped me compute the correct volume and port dimensions for the 24hz tuning by using speaker design software, I forget the name of the software. I then did some additional research on construction methods. It is really just a bass reflex box with a port, but designed with every consideration I could find out about. I would say, yes, it is the most important aspect of my system without a doubt.

Since I play a wide variety of media from old mono LPs to good Stereo LPs to CDs and even 78s on occasion, I really enjoy having the ability to manipulate things with the electronic crossover. I don't really like playing with an equalizer even though theoretically that might be a way to help tune one's system to the room. The electronic crossover is all the control I seem to need or want at this point.

I would say the next most important aspect is the preamp. The other key is having lots of clean power for the bass. I notice the meters on this SS Carver going up over 100watts on peaks when I have the volume up where I like it sometimes. I have all the headroom needed here, in fact all around. The other two tube amps are both pp in triode. The mids go through the newly upgraded MarkIIIs (6550s) and the highs (horn and tweeter) go through the mod Dynaco70 El34s. I am not really a tube roller. The system sounds good and most of the time I am more concerned with rolling the LPs..... as it is, I have to make time to refile LPs because I end up with a pile of them every evening that need to be re-shelved. Tube rolling would be too time consuming with having to adjust bias every time. I am too anxious to get back to the music.....

C&S