lovechild said:
This is correct. Active may make this easier, but I would still caution that this is a major undertaking. One of the main things that I have found makes the Summa so good is the crossover design (some 20 components in all, many custom made for us). The design is done not to yield a flat response on-axis, which isn't too hard, but to yield the flatest and smoothest polar response on and off axis. This is very difficult. If you equalize to a flat response along any single axis, you will screw up the overall polar response.
I really believe that this later technique is beyond the DIYer - it took me years to develop the procedure to do this, and I was not a novice when I started.
Ummm, Is doing a really decent job of building any kind of speaker easy? An MTM or OB? Look at Lynn's thread.
I didn't think for a second this is going to be a quick project. I built my first speakers in the sixties and I've found it's never been easy to get stuff right.
I didn't think for a second this is going to be a quick project. I built my first speakers in the sixties and I've found it's never been easy to get stuff right.
lovechild said:
"some equalization" is an understatement 🙂
In order to attain flat response out to 20khz with a compression driver, you have to apply LOADS of eq in the top octave. On the order of 10-15db. The need for EQ is exacerbated by the use of the HOM-reducing plug. These two things reduce the overall efficiency of the compression driver of course. For a hifi application, this is a reasonable tradeoff. If I'm not mistaken, power handling shouldn't be much worse, since compression drivers are typically excursion limited.
Patrick Bateman said:
Well actually they are more likely thermal limited. But you are correct that the "EQ" is a blessing in that what one is really doing is cutting out a lot of low frequencies - and excursion. At one point I estimate that the compression driver is padded down by about 16 dB. Still, in practice, its the compression driver that compresses the most. We are talking some very high SPL's however - like 120+ dB at 3 meters.
This has been really interesting! I'm told that building a Summa-like speaker will cost me as much, or more, than buying ESP15s.
The used DE500's cost me $84. Even if I bought the TBX100s new, and the waveguides from Earl, I'm looking at $1100 so far and the actual speaker cabinets are "small". Let's say $500 for box materials. I'm thinking a cost between $1700 - 2000.
I'm tri-amping an ancient horn system so I've already got the electronic gear to run it and develop a crossover/eq either quick and dirty or eventually refined.
So let me bite the bullet: what's a pair of ESP15s going to cost me, landed, in Canada?
The used DE500's cost me $84. Even if I bought the TBX100s new, and the waveguides from Earl, I'm looking at $1100 so far and the actual speaker cabinets are "small". Let's say $500 for box materials. I'm thinking a cost between $1700 - 2000.
I'm tri-amping an ancient horn system so I've already got the electronic gear to run it and develop a crossover/eq either quick and dirty or eventually refined.
So let me bite the bullet: what's a pair of ESP15s going to cost me, landed, in Canada?
FrankWW said:
Well your number here is about 10% of the reality. You see the tooling for a Summa cost me about $5000 and each enclosure was about $750 - unfinished. The drivers in the final analysis are not even worth worrying about cost wise, which is why we can afford to import drivers from Itally when drivers can be made next door in China for a fraction of this cost. You see, you can't do what I did with the Summa in wood. I've had people say they could, but when I ask for a quote I get no response. The baffle can only be cut on a numerical mill and these get pricy to do.
This is why I had to move production to Thailand where these costs are much less.
I'm not going to argue with you about costs, but I will say that I'd bet a years salary on the fact that in the end a group of people would select my design as the better sounding. Its simply not that easy to do. I've spent full time on this project for years.
Good luck anyways.
MBK said:
I didn't see it this way, but the point is that getting the speakers to Canada is the expensive part.
ESP15's will MSRP for about $4500 each. Thats not the dealer price nor is it the price that I would ask if you were serious about buying a pair. But the shipping costs - that could get expensive - until we have the US dealer network in place.
Dear Dr. Geddes:
Would it be possible to explain the concept without giving up implementation details?
Thank you,
M
Would it be possible to explain the concept without giving up implementation details?
Thank you,
M
Hello Earl,
I just found this thread today and have spent the last several hours reading it.
Back on June 22 you posted about using two Summas (or ESP-15's) per channel in some applications. How would you configure them - in a splayed array side-by-side, or stacked one atop the other (presumably with the top one standing on its head), or some other configuration I haven't thought of?
Also, is there a significant effect on the power response from the interference between the drivers?
Thanks,
Duke
I just found this thread today and have spent the last several hours reading it.
Back on June 22 you posted about using two Summas (or ESP-15's) per channel in some applications. How would you configure them - in a splayed array side-by-side, or stacked one atop the other (presumably with the top one standing on its head), or some other configuration I haven't thought of?
Also, is there a significant effect on the power response from the interference between the drivers?
Thanks,
Duke
mefistofelez said:
http://www.pispeakers.com/AES_v31_n6_p408.pdf
There you'll find what you want to know 😉
Cheers,
Christoph
Hi Earl, my best wishes for your stay and projects in Bangkok. I look forward to seeing the website.
That I believe. I've always thought the crossover/eq and box are going to be difficult which is why I've put off the project for a couple of years.
That I believe. I've always thought the crossover/eq and box are going to be difficult which is why I've put off the project for a couple of years.
audiokinesis said:
Hey Duke
How are you? I am posting here quite a bit as - for the most part - people are polite and respectful (unlike my past experiences at other sites.)
The Summas were not originally designed to be arrayed, unlike the ESP10's which we have deliberately considered that aspect. But we do have some experience with arraying the larger units.
You are correct that one over the other, top one flipped, is what we do, These are then slanted relative to each other. There will be some lobing - no doubt, but it appears to be acceptable. In the clubs that we have done this we get an incredible amount of sound and a very clean perception. Here, in Bangkok, we are selling these speakers very well to clubs as the typical club here has a very poor sound. Thus when you do one that is exceptional, it becomes the standard.
Earl,
Thanks once again.
I have been busy!
Been working almost 'round the clock the past few days but I'm finally seeing the light at the end of the tunnel. I''ve been trying to get a new pair of speakers ready for the Rocky Mountain Audio Fest, and tonight I finally got one speaker put together. Now it's 2 AM and that single speaker sounds great. Probably because the electrons are more plentiful at night, and the dielectric of the interconnect is energized by moonbeams.
Okay not all of that was totally serious...
I'll give a brief description of what I'm doing over on the thread entitled "The objectives of a loudspeaker in a small room", as I think that topic would be a better fit.
Duke
Thanks once again.
I have been busy!
Been working almost 'round the clock the past few days but I'm finally seeing the light at the end of the tunnel. I''ve been trying to get a new pair of speakers ready for the Rocky Mountain Audio Fest, and tonight I finally got one speaker put together. Now it's 2 AM and that single speaker sounds great. Probably because the electrons are more plentiful at night, and the dielectric of the interconnect is energized by moonbeams.
Okay not all of that was totally serious...
I'll give a brief description of what I'm doing over on the thread entitled "The objectives of a loudspeaker in a small room", as I think that topic would be a better fit.
Duke
audiokinesis said:
You can take comfort that you're not the only one in that boat. 😉 There will be more than one pair there with varnish, paint and glue barely dry....