POOH,
Radian has their 10" coax with a compression driver that can work also. What I am not thrilled about is their use of polypro cone material on the cone side of things, a ponderous kind of sound. That was the reason I had them make me paper cone drivers when I was using their devices. It surely didn't hurt that my friend was one of the designers there back in the day and R. Contramous would build me what I asked!
Radian has their 10" coax with a compression driver that can work also. What I am not thrilled about is their use of polypro cone material on the cone side of things, a ponderous kind of sound. That was the reason I had them make me paper cone drivers when I was using their devices. It surely didn't hurt that my friend was one of the designers there back in the day and R. Contramous would build me what I asked!
How so!? As long as the diaphragm excursion does not cause it to hit the phase plug at maximum listening levels then there is no advantage to a larger format. This has never happened to me and I listen loud. And don't give me that "lower THD" argument as that is simply not a valid concern.
One can always call any solution a "compromise", but with the above "solution" in place I believe that this approach offers the best possible compromise over any other "solution".
Crossing over lower does require a larger diaphragm or longer excursion. Little 1" drivers struggle with this and sound that way when compared with using a driver designed to do that like a CMCD JBL compression driver or the Community M200. The little drivers sound fake and thin. They also sound that way compared to a good horn loaded cone. Using a little 1" driver beyond it's capabilities doesn't seem like a very intelligent path. The same goes for using a real horn laded midrange driver for treble. It's like expecting a toyota corrolla to take the place of a Mack truck. Sure if it works for you it's OK but I'll keep my Mack. That's why they build bigger drivers to handle the lower ranges as they build corrolla's for economy and mack's for hauling freight.
I don't. And I think that my approach is pretty intelligent. All of the measurements indicate that. I will believe in the measurements more than some pointless comparisons between a Mack and a Corolla.
It is like comparing a great Harley with a light footed 1000cc Honda 4 cylinder bike. I put fidelity and refinement before power, especially if its for a DHT amp and not a gutsy SS amp. But both have a place.
My money is on fidelity/refinement fine detail first. For the outdoor party my money is on the other 2nd.
And measurement does get you some way, but you cannot measure variables we do know or understand yet, where there is no clear scientific parameter. And they are there. The known unknowns.
If the small driver sounds thin or fake (silk diaphragms may)
then it is like the Honda 2 stroke twin i.e the wrong small driver.
A small metal domed driver can be a tough agile cookie.
Fidelity and refinement is probably not what one associates with a Harley... refinement certainly not.....
Aurora,
I think of most Harley's like the guy in the car with subwoofers and the only thing you notice is every rattle of loose metal on that car. not refined in the least! I'd much rather have the guy on the Honda or BMW go by me, at least I will still have my hearing and won't be annoyed.
I think with speakers it is the nuances that make one sound great and another just sound competent. I would rather have a little shy bass but all the details rather than a HT type of speaker that just rattles the room and makes you wonder who they are trying to impress.
ps. I you want a refined cruiser look at a Honda Gold Wing or even an Indian, at least they will stay on the road and not end up at the mechanic all the time like a Jaguar!
I think of most Harley's like the guy in the car with subwoofers and the only thing you notice is every rattle of loose metal on that car. not refined in the least! I'd much rather have the guy on the Honda or BMW go by me, at least I will still have my hearing and won't be annoyed.
I think with speakers it is the nuances that make one sound great and another just sound competent. I would rather have a little shy bass but all the details rather than a HT type of speaker that just rattles the room and makes you wonder who they are trying to impress.
ps. I you want a refined cruiser look at a Honda Gold Wing or even an Indian, at least they will stay on the road and not end up at the mechanic all the time like a Jaguar!
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Some years ago, on a warm summer day ( they do happen, even at 69N 🙂, I stopped at a countryside cafe for a rest and coffee. Some german tourists were also there.... it actually took a while before I realized that one of the R1100's was actually running at idle.. I had to get up close to listen to it.....
Just FYI. The Altec A7 used a 1" compression driver and was crossed 2nd order at either 500Hz or 800Hz depending on the horn used. It worked, but didn't sound great. The Altec A5 used the same bass unit but with a multicell horn and a 1.4" driver. A very different sound.
For either, the stock crossover was far from optimal for Hi-Fi. Ditto the box tuning.
I agree with Gary that the 1" drivers just don't compare to the bigger boys. Unless crossed rather high or used at very low drive levels, they always sound strained to me. The problem with the bigger drivers and horns is the response above ~8Khz. Not easy to extend another octave or so.
Related to all the super tweeter / vertical spacing stuff, I have been playing with this a bit on my system - so far just in software using previously measured data while I work on cabinets and horns for the second side of my system. My current system and measured performance can be seen in post 12266 here, and I've been listening to this for about 7 months now. I quite like it, but there is definitely room for improvement.
http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-614.html#post4173924
It uses a 1.5" exit JBL 2435 driver on a 380Hz LC horn and a JBL 2402 on a custom LC horn I built. In the data I showed in that post, you can see that I have dips in the vertical polar rseponse and corresponding peaks in the directivity index plots, both for directly on axis and for a listening window (an average over an area, not just a point). I found that I could smooth out the transition in the listening window and power response through both crossover points by doing some tweaking of the crossover slopes and frequencies. Basically I changed to these cascaded acoustic slopes for the mid to tweeter:
Tweeter:
9k 1st BW HP
2.5k 2nd BW HP
Mid:
15k 1st BW LP
6k 2nd BW LP
Then I eq the final response to flat on-axis (or whatever I want) although these slopes sum to almost flat as-is. I also need a delay of 2 samples at 48kHz on the tweeter to align it, or about 0.5" from where I have it positioned. Below are some plots showing the predicted responses (on axis, listening window, power response) showing no big dip at crossover (7k for the tweeter to mid) and fairly flat DI through the crossover. The one part I'm interested in listening to is the lobing in the vertical 3k-6kHz range. I can push that lobing around, but I end up trading off smoothness of the listening window response and DI. Also, to be clear I have normalized the measured response to flat on-axis for each driver and then applied filtering to those normalized responses before recombining things to see total performance. It just makes it easier to look at what just the filters are doing, and since I'm using DSP filtering, it's not much of a stretch. However you could do the same things with passive filtering - I'm not doing anything too crazy or using tons of delay. The midbass would need to be moved about 2" back from where it is relative to the mid horn in my picture in the other post.
http://www.diyaudio.com/forums/multi-way/100392-beyond-ariel-614.html#post4173924
It uses a 1.5" exit JBL 2435 driver on a 380Hz LC horn and a JBL 2402 on a custom LC horn I built. In the data I showed in that post, you can see that I have dips in the vertical polar rseponse and corresponding peaks in the directivity index plots, both for directly on axis and for a listening window (an average over an area, not just a point). I found that I could smooth out the transition in the listening window and power response through both crossover points by doing some tweaking of the crossover slopes and frequencies. Basically I changed to these cascaded acoustic slopes for the mid to tweeter:
Tweeter:
9k 1st BW HP
2.5k 2nd BW HP
Mid:
15k 1st BW LP
6k 2nd BW LP
Then I eq the final response to flat on-axis (or whatever I want) although these slopes sum to almost flat as-is. I also need a delay of 2 samples at 48kHz on the tweeter to align it, or about 0.5" from where I have it positioned. Below are some plots showing the predicted responses (on axis, listening window, power response) showing no big dip at crossover (7k for the tweeter to mid) and fairly flat DI through the crossover. The one part I'm interested in listening to is the lobing in the vertical 3k-6kHz range. I can push that lobing around, but I end up trading off smoothness of the listening window response and DI. Also, to be clear I have normalized the measured response to flat on-axis for each driver and then applied filtering to those normalized responses before recombining things to see total performance. It just makes it easier to look at what just the filters are doing, and since I'm using DSP filtering, it's not much of a stretch. However you could do the same things with passive filtering - I'm not doing anything too crazy or using tons of delay. The midbass would need to be moved about 2" back from where it is relative to the mid horn in my picture in the other post.
Attachments
Pano,
Where were they using the 311B horn if not in an A7 type enclosure. I guess that was a 1.4" driver on that, it has been way to long to remember! There was just so little top end to those large 1.4" Altec drivers that I grew up with doing PA. Moved my share of A2's, not much fun.
Where were they using the 311B horn if not in an A7 type enclosure. I guess that was a 1.4" driver on that, it has been way to long to remember! There was just so little top end to those large 1.4" Altec drivers that I grew up with doing PA. Moved my share of A2's, not much fun.
I know that measurements don't mean anything (except to people like Floyd Toole and the like, myself included) but I know of no measurements that support your opinion. It just sounds like "bigger is better" to me. Not always the case. There are some very fine 1"drivers.
That's a nice compact system John! I like how how you used the filters to pad down the out of band nastys. The 2435 is a serious driver. I like the 2225s too.
How does this compare with that unity clone you built?
Honestly it's been a couple of years since I listened to my unity horn, and I'm in a new room now so it's tough to compare. I can say I have this one voiced much better, but that's not really anything inherent in the basic designs of the systems.
I don't understand why your record is stuck in that groove. Perhaps you have mistaken me for someone else? I'm a measurement fanatic!
I can probably find some measurements that will relate to an audible sense of straining or audible artifacts in 1" vs 1.4" or 2" drivers at home levels. Yes, there are some fine 1" drivers on the market - no argument there.
Part of it is "bigger is better", to be sure. I tend to prefer a larger source size than smaller. Not always, but usually. The big mouth horns I like are mostly driven by 1.4" throats, which may be part of my prejudice. Some experimenters have reported very good results with 1" drivers on the same horns, with a slightly longer horn throat. I have not heard these, tho.
There were so many variations of Altec commercial speakers over the years, it's hard to keep track! 🙂 All the A7s I ever saw used 811 or 511 horns and 1" drivers. The 311B horn I've only ever seen removed from whatever it came with.
A7's always had 1" drivers. The A7-500 used a 511 horn, and the A7-800 used an 811 horn. If you used a 1.4" driver then it was an A5. The 311-60 and 311-90 were sectoral horns with 1.4" throats. Then of course there were the multicell horns, the most popular ones with nominal flare rates of 300 Hz and 500 Hz. I believe these multicells had separate throats (single or double) designed for 1.4" drivers. The 21216 adapter could be used to mount a 1" driver on a 1.4" throat.
Gary Dahl
Gary Dahl