Hi Earl
Agree about lack of facts in audio.
The material on Ted's site is somewhat simplified. I thought the polar responses are on the pages for the individual drivers but my mistake. Much of what he has researched has appeared in Wireless World over the years and I think I must be recalling some of those articles, which include more measurements. I'm hoping we'll be able to get reprints of the material onto his website in the next year or so.
Anyway, getting off the topic slightly.
Agree about lack of facts in audio.
The material on Ted's site is somewhat simplified. I thought the polar responses are on the pages for the individual drivers but my mistake. Much of what he has researched has appeared in Wireless World over the years and I think I must be recalling some of those articles, which include more measurements. I'm hoping we'll be able to get reprints of the material onto his website in the next year or so.
Anyway, getting off the topic slightly.
gedlee said:
That's THE problem of the set up described by Graaf. In his case (mine as well for the moment being) the drivers should be flat off axis up to almost 180º...
If you've seen a driver like this, please tell me! 
In our current set ups, the higher the frequency, the less direct sound we get. It is done in a quite progressive way so that it doesn't feel that wrong. Then if you read Briggs's book: Loudspeakers, at that time they recommended to have the medium and tweeter facing upward in order to achieve more spaciousness. The best tweeters of that time went up to 12kHz, maybe 15kHz... I wonder when LS started to have forward firing drivers???
Looking at this link, we can see that the FE167E (my current driver) is not that bad on axis but omnidirectional only up to 2kHz.
I will try to lift my LS up so that I can see them behind the couches. This could improve the situation since I will get more direct sound. But it could as well worsen it since i will be listening more and more off axis...
Any experience about multiple drivers in this set up?
I have the feeling that it should not be a problem below around 200Hz (where the room modes start to be discrete) but my concern is with the mid high transition. I guess the delay caused by the distance between the 2 drivers will be audible. So that coaxial speaker would be a better choice. Just guessing, any thoughts?
Regards,
Etienne
gedlee said:
Earl, with multiple drivers I meant a boomer, a midrange and a tweeter. I am not sure my message was clear since I know you use subwoofers! If I understand you well, you use one single driver per channel to cover 150-200Hz to 20kHz. Is that right? That is 7 octaves, it is huge and I think I know what I'm talking about since I use a full range driver.
Do you manage to get flat response from 0º to 45º on 7 octaves with your horn design?
Regards,
Etienne
Etienne88 said:
I use subs below about 150 Hz. The mains have large woofers operating from about 50 Hz through about 900 Hz. The waveguide take over from there. The woofers are large so that they have narrowed their directivity down to that of the waveguide at the crossover frequency. The waveguides are completly CD above 1 kHz where they match the woofer - thats about 4 octaves, not seven. The need for directivty drops below 1 kHz for psychoacoustic reasons (thank god because it wouldn't be very easy to do). The 4" driver is never CD, except when its omni. But omni is a disaster in a small room with wall reflections (again unless these are below about 500 Hz.)
Etienne88 said:
You have to make sure that the midrange has still an omnidirectional radiation pattern at the crossover point. Otherwise the direct sound will have a hole in the FR in a critical region. My trial in the multi-way direction will be a narrow-beam CD-horn radiating hardly any sound in the listener´s direction, combined with either front-firing or ceiling-firing midrange.
gedlee said:
fortunately we have at least some believable data and independent measurements of the Jordans JX92s, those 4''
see: http://www.hifisound.de/oxid/out/oxbaseshop/html/0/test_pdf/EJJ-1110858.pdf
are they very terrible? I don't know - just layman asking
certainly they are not CD but are they terrible?
"ganz sicher ein ausnahmelautsprecher" they wrote
gedlee said:
well, again, what do I know? certainly not much
but I wouldn't call what I hear "a disaster"
neither would Etienne88 I believe
in fact Etienne88 seems to think something quite the contrary, at least this is how I understand what he has written earlier in this thread
correct me if I am wrong
best,
graaf
graaf said:
are they very terrible? I don't know - just layman asking
certainly they are not CD but are they terrible?
Plotted on a 60 dB range. They are not very flat, very smooth or CD. I wouldn't use them.
well, again, what do I know? certainly not much
but I wouldn't call what I hear "a disaster"
neither would Etienne88 I believe
in fact Etienne88 seems to think something quite the contrary, at least this is how I understand what he has written earlier in this thread
correct me if I am wrong
You are mixing subjective with objective here. I can't resolve your subject concerns, I can only talk about the "right" thing to do based on the data that we have. And as the guy who posted the other day about his opinions of my system I'd have to claim that the objective approach works pretty well.
In hifi, it is hard to choose between subjective and all what it implies (you know, there should be place for all the tastes in nature...) and objective where measurements of different things are used without fully understanding all the principles behind...
For my part I am a hard believer in science, but I know as well that there is a long way left to go before science can explain everything!
So between subjective and objective, I choose both because they should meet at perfection.
What I really like with this set up is the fact that the sound is there, just there, not thrown in your face. But then Fostexes have the reputation of being a bit shouty... but not to my taste (I listened to them of axis when they were standing in a more "conventional" way, if it is of interest)
It all comes down to compromise at the end! I tried both solutions and they both have their advantages and drawbacks. Which advantages I value the most is subjective, isn't it?
I lifted up the LS so that the driver is at the same height as the armrest of the couches. So far it seems to be an improvement but I did not listen to that much music.
Regards,
Etienne
For my part I am a hard believer in science, but I know as well that there is a long way left to go before science can explain everything!
So between subjective and objective, I choose both because they should meet at perfection.
What I really like with this set up is the fact that the sound is there, just there, not thrown in your face. But then Fostexes have the reputation of being a bit shouty... but not to my taste (I listened to them of axis when they were standing in a more "conventional" way, if it is of interest)
It all comes down to compromise at the end! I tried both solutions and they both have their advantages and drawbacks. Which advantages I value the most is subjective, isn't it?
I lifted up the LS so that the driver is at the same height as the armrest of the couches. So far it seems to be an improvement but I did not listen to that much music.
Regards,
Etienne
gedlee said:
I am not mixing anything I can assure You
I perfectly understand Your point of view and I agree with You
ok what data do You have?
have You measured such a setup as described in my first post in this thread or as in Etienne88's post?
"omni in a small room" can be different things
I accept that what one hears is irrelevant, the "brain-ear reference" is misleading us
but where can we find any measurements confirming that such a setup is a disaster, that is not "right"?
if You are saying "this is a disaster" then give us some data please
best,
graaf
No, the JX92s are not terrible. Or, at least, I don't think so. In fact, I rather like them. The JXR6 and other drivers measure better, go higher etc but within their limits, the JX92s have a superb-sounding mid and spacious imaging. I'd love to hear some of Earl's designs but it's impractical at this remove. I have heard louder, more dynamic designs than the Jordans but so far I've only heard the Quad ESLs that I would prefer to them.
Back to the thread ....
Back to the thread ....
graaf said:
I have given you the data, it has to do with VER, etc. Look at the impulse response of an omni speaker in a small room. There will be a multitude of VER under 10 ms. This is not "right" no matter what you find subjectively. To me this is a "disaster" (perhaps the word is a bit flowery in description, but clearly this approach is not what I am striving for.)
gedlee said:
I understand that VER are not right
I sincerely believe that You are right
but I ask about this specific omni setup that I have proposed
I am quite certain that no measuments of impulse response of such a setup were ever made, because I sort of just invented
this setup myself And I believe that this setup is very different from a typical "omni speaker in a small room"
can We calculate reflections' delay the way I did it in my first post using law of reflection?
or is anthing wrong with that?
I don't assume anything
I have no impulse response measurement of such a setup and I seriously believe that nobody has
therefore I calculate
perhaps oversimplifying
then tell me what is wrong please
best,
graaf
