altec stonehenge V plans

[dbale]

Right, narrower baffles roll off the lower frequencies as they fold back away due to being so large compared to it. This is called baffle step loss, so the narrower the baffle, the higher in frequency this begins. Consequently, narrow baffles typically need baffle step compensation [BSC] unless the speaker isn?t too deep and pushed up against a wall or in a corner.

Large Altec, etc., speakers are wide enough that shelving down the mids/HF to flat or a little lower is usually sufficient since it will be combining with the room?s gain.



GM

Will there be much of a difference between the stonehenge V(22") or the altec 620(26") cabinets baffle width in room ?

Is baffle height just as important? What are the trade offs?

[Old Guy]

Is baffle height just as important? What are the trade offs?

I will leave details to Greg. But if baffle height was not important would wings on old Altecs extend upward? So yes IMHO.

[jmathers]

Sounds proportionally about right based on looking at this: Iconic Speaker Manufacturing - Stonehendge Page

Right, narrower baffles roll off the lower frequencies as they fold back away due to being so large compared to it. This is called baffle step loss, so the narrower the baffle, the higher in frequency this begins. Consequently, narrow baffles typically need baffle step compensation [BSC] unless the speaker isn?t too deep and pushed up against a wall or in a corner.

Large Altec, etc., speakers are wide enough that shelving down the mids/HF to flat or a little lower is usually sufficient since it will be combining with the room?s gain.

FYI, MJK has temporarily made them available again for his yahoo! Group members, so join up if you?re interested: https://groups.yahoo.com/neo/groups/.../messages/3995

GM

Thanks for the tip on MJK's yahoo group. I've requested membership.

Thanks too for the baffle explanation - it's a little clearer to me now.

[Old Guy]

Thanks too for the baffle explanation - it's a little clearer to me now.

GM knows his stuff.

[Todd W. White]

The V works MUCH better than the III.

I have the plans for the Stonehenge V - contact me directly about them.

[GM]

Will there be much of a difference between the stonehenge V(22") or the altec 620(26") cabinets baffle width in room ?

Is baffle height just as important? What are the trade offs?

Well, it?s important in the sense that the frequencies are expanding exponentially with decreasing frequency, so to the first approximation it?s all about area, but if it?s a very high aspect ratio one such as a line array baffle might have, then it?s contribution rapidly decreases with decreasing frequency and at about 1/3 WL it becomes acoustically transparent, leaving only its width roll off to account for.

A HIFI/HT speaker?s height then is more about getting the driver up to an appropriate listening height for the app and in the case of a MLTL, making it tall enough at this driver position to also be at one of the optimum locations along its length, so normally I calculate the speaker?s height as a function of driver/floor distance.

Anyway, a 22? wide baffle rolls off ~20 % higher in frequency than a 26? wide one, so normally some efficiency must either be traded or boosted to flatten the response out to match the wider baffle?s tonal balance unless the room?s gain curve is great enough to offset the difference, in which case the wider baffle might need attenuating. Since boosting increases distortion, it?s always best to attenuate and why I promote large cabs tuned low no matter the room size.

GM

[jmathers]

The V works MUCH better than the III.

I have the plans for the Stonehenge V - contact me directly about them.

Got to get my post count up I guess before I can PM you.

[bowtie427ss]

Got to get my post count up I guess before I can PM you.

If he hasn't done so already, maybe ask Todd to PM you. That should allow you to reply to him.

[dbale]

Well, it?s important in the sense that the frequencies are expanding exponentially with decreasing frequency, so to the first approximation it?s all about area, but if it?s a very high aspect ratio one such as a line array baffle might have, then it?s contribution rapidly decreases with decreasing frequency and at about 1/3 WL it becomes acoustically transparent, leaving only its width roll off to account for.

A HIFI/HT speaker?s height then is more about getting the driver up to an appropriate listening height for the app and in the case of a MLTL, making it tall enough at this driver position to also be at one of the optimum locations along its length, so normally I calculate the speaker?s height as a function of driver/floor distance.

Anyway, a 22? wide baffle rolls off ~20 % higher in frequency than a 26? wide one, so normally some efficiency must either be traded or boosted to flatten the response out to match the wider baffle?s tonal balance unless the room?s gain curve is great enough to offset the difference, in which case the wider baffle might need attenuating. Since boosting increases distortion, it?s always best to attenuate and why I promote large cabs tuned low no matter the room size.

GM

GM,thanks for the detailed reply.

[jmathers]

If he hasn't done so already, maybe ask Todd to PM you. That should allow you to reply to him.

Yes, seems logical. But how do I ask him if i can't PM him? Up to 6 posts now so getting there. I just hate to post for postings sake.