Yes of course, that's why I've said I owe you ....(and the phone company)
Yes I see what you mean. To be honest I haven't heard just the four TB's without a tweet or horn in a long time, and always seem to be standing above them while making changes. I originally played with running them 3/2/1.5 way but I appreciate the adviceand your schematics playing with the filters, I'll do more of that.
BTW, I_did_ hammer these out on a Sunday, and have built 3 other designs since.(Two TLs and a Vifa BR, all 2 ways)..... With a sub, and especially the $$, these are in a league of their own.
Kewl.... SPLs, you'll get. You could build a pair cheap, you know? I've got a big case on the way myself, and I'm dreaming about a curved baffle, but I keep thinking, "Why not convex, rather than concave?"
Maybe I'll try both. But I sure wish someone would help me find the right horn. My fav is an old cast RS, that's out of production.
Nonsuch 4 - Report on the state of play
After some days of theorizing and playing with inductors, etc. I have taken a decision re. adding a filter to the outer drivers of the Nonsuch 4 and I'd like to explain my reasoning.
The decision is 'no filter.'
You may remember that the function of the filter was to
a) reduce the combing effect to allow more flexibility in vertical listening position and ...
b) partially compensate for the baffle diffraction step.
Dealing with the baffle step compensation issue first ...
It turns out that the situation is a little more complex than I had at first thought. I'm using four full-range drivers. Each driver has a fairly flat frequency response over its working range (100Hz-20kHz) when used singly and mounted in a large open baffle. As I'm using four, the efficiency increases by a little under 6dB. However, this gain only applies to the bass frequencies below c/(Pi*r) where c is the speed of sound and r is the driver radius. With the Nonsuch 4s the gain starts to come in below about 4kHz, probably reaching it's maximum an octave or two lower.
In other words, the efficiency gains from using four drive units partly compensate for the diffraction step.
I could build a filter which would give a still flatter frequency response curve but whenever I put components in between the drivers and the power amplifier the stereo imagery deteriorates noticeably and the speaker loses clarity.
After listening to any reasonably good speaker for a length of time (an hour?) the 'ears' adjust to the frequency spectrum. For example, if you were listening to a good speaker with a peak in the lower mid-range and then you changed over to a good speaker with a flat response, the flat speaker would sound colored with a trough in the mid-range to correspond to the peak to which you had become habitualized.
In other words, the brain automatically adjusts for frequency response.
Unfortunately, I don't know of a mechanism by which the brain can adjust to loss of clarity or deterioration of the stereo image.
So no filters for the Nonsuch 4 - still as pure as the driven snow.
But what, I hear you ask, about the comb effect? Don't I want to hear the high frequencies better when I stand up to listen?
Well, not particularly. It's quite pleasant to be able to partially withdraw from the sound-field experience from time to time. It's like the intermission at a concert - make tea, grab a beer.
Incidentally, for those interested, The Nonsuch 4s with Little Awesome(s) will be reviewed in the Hi-Fi + edition coming out in October or November. What, me nervous?
After some days of theorizing and playing with inductors, etc. I have taken a decision re. adding a filter to the outer drivers of the Nonsuch 4 and I'd like to explain my reasoning.
The decision is 'no filter.'
You may remember that the function of the filter was to
a) reduce the combing effect to allow more flexibility in vertical listening position and ...
b) partially compensate for the baffle diffraction step.
Dealing with the baffle step compensation issue first ...
It turns out that the situation is a little more complex than I had at first thought. I'm using four full-range drivers. Each driver has a fairly flat frequency response over its working range (100Hz-20kHz) when used singly and mounted in a large open baffle. As I'm using four, the efficiency increases by a little under 6dB. However, this gain only applies to the bass frequencies below c/(Pi*r) where c is the speed of sound and r is the driver radius. With the Nonsuch 4s the gain starts to come in below about 4kHz, probably reaching it's maximum an octave or two lower.
In other words, the efficiency gains from using four drive units partly compensate for the diffraction step.
I could build a filter which would give a still flatter frequency response curve but whenever I put components in between the drivers and the power amplifier the stereo imagery deteriorates noticeably and the speaker loses clarity.
After listening to any reasonably good speaker for a length of time (an hour?) the 'ears' adjust to the frequency spectrum. For example, if you were listening to a good speaker with a peak in the lower mid-range and then you changed over to a good speaker with a flat response, the flat speaker would sound colored with a trough in the mid-range to correspond to the peak to which you had become habitualized.
In other words, the brain automatically adjusts for frequency response.
Unfortunately, I don't know of a mechanism by which the brain can adjust to loss of clarity or deterioration of the stereo image.
So no filters for the Nonsuch 4 - still as pure as the driven snow.
But what, I hear you ask, about the comb effect? Don't I want to hear the high frequencies better when I stand up to listen?
Well, not particularly. It's quite pleasant to be able to partially withdraw from the sound-field experience from time to time. It's like the intermission at a concert - make tea, grab a beer.
Incidentally, for those interested, The Nonsuch 4s with Little Awesome(s) will be reviewed in the Hi-Fi + edition coming out in October or November. What, me nervous?
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