I know it's a lot of money, but I find myself in this situation very often. What I have found is that I waste so much money "getting my feet wet."
I figure your way is going to cost a minimum of 1500 dollars for a complete pair, Geddes kits would be 2500, which is more, but I think worth it. What if, in getting your feet wet, you find yourself failing to design something as good, and feeling the design is flawed, never fully realizing what you could have had?
While this is now off the topic of foam, I took measurements of the waveguide/driver when building the kit so I could model my own crossovers. What I find is that, while I can design crossovers for my own designs just fine, waveguides are a bit tricky. My biggest issue, regardless of radiation style, is phase. Before stumbling uppon Dr. Geddes design, which uses a similar crossover approach, Joe Rasmussen crossover designs I began using this approach. I found it very "fiddly" getting that balance between a flat axial and power response, and good phase behavior. In fact, what I found was, once you ignore the phase issue and use more traditional crossover approaches, you end up with a poor polar response, namely nulls as you go off axis.
Another pitfall I see quite often is the mistaken belief that electronic crossovers solve these problems. I'm not sure why people think sound cares if it's crossed over at the high level signal or low level signal with regard to phase. Just because an electronic crossover is capable of linear phase doesn't mean your results will be linear phase. I have the ability to measure acoustic phase, and while my measurements are a bit "noisy", they are still interpretable enough to know if the response shows a generally linear phase or not. What I look for is a phase response which basically goes from around 95-100 degrees at the low end to 45-50 degrees at the high end in a straight and linear fashion. No big phase shift at the crossover point. Speakers that can do this correctly require very careful crossover design.
I figure your way is going to cost a minimum of 1500 dollars for a complete pair, Geddes kits would be 2500, which is more, but I think worth it. What if, in getting your feet wet, you find yourself failing to design something as good, and feeling the design is flawed, never fully realizing what you could have had?
While this is now off the topic of foam, I took measurements of the waveguide/driver when building the kit so I could model my own crossovers. What I find is that, while I can design crossovers for my own designs just fine, waveguides are a bit tricky. My biggest issue, regardless of radiation style, is phase. Before stumbling uppon Dr. Geddes design, which uses a similar crossover approach, Joe Rasmussen crossover designs I began using this approach. I found it very "fiddly" getting that balance between a flat axial and power response, and good phase behavior. In fact, what I found was, once you ignore the phase issue and use more traditional crossover approaches, you end up with a poor polar response, namely nulls as you go off axis.
Another pitfall I see quite often is the mistaken belief that electronic crossovers solve these problems. I'm not sure why people think sound cares if it's crossed over at the high level signal or low level signal with regard to phase. Just because an electronic crossover is capable of linear phase doesn't mean your results will be linear phase. I have the ability to measure acoustic phase, and while my measurements are a bit "noisy", they are still interpretable enough to know if the response shows a generally linear phase or not. What I look for is a phase response which basically goes from around 95-100 degrees at the low end to 45-50 degrees at the high end in a straight and linear fashion. No big phase shift at the crossover point. Speakers that can do this correctly require very careful crossover design.
I do not need crossovers or boxes and I would want the abbey kits which might be around $500 per kit (Maybe??) . My prototype is around $200 per kit (audiokarma econo waveguide project) and I have several TD12s from AE sitting around unused.
Its very important for me to understand the audiable differences in the end because measurements are only part of any solution.
Im sure I will spend well over $3K on this project overall...I have 3 different waveguides on house already, the Selenium D220 CDs in house and the BMS 4552 on order.
I just wish someone would order a batch of those Chinese knock off CDs for $15 each
Its very important for me to understand the audiable differences in the end because measurements are only part of any solution.
Im sure I will spend well over $3K on this project overall...I have 3 different waveguides on house already, the Selenium D220 CDs in house and the BMS 4552 on order.
I just wish someone would order a batch of those Chinese knock off CDs for $15 each
Hi guys. I might just buy some of those Chinese CD's when I am there later this summer, but I certainly won;t sell them for $15. Likely I will only use them in my own products.
To further support what Mat is saying consider this. I would have to be pretty bad at this whole design process - waveguides, crossover, etc. - if after doing it and refining the design over some five years or more I didn't get something that was better than a novice could do in a shorter period of time. Quite honestly, there is simply no way that you could do as good a crossover as I have done even if you use my waveguides and foam plugs. I have custom tools, a good measurement setup, a not insignificant amount of experince and well, quite honestly, a knowledge level that not many others have.
If you want to "play" with waveguides and crossovers for the fun of learning that's great, really, have a ball. But don't kid yourself that you will get anywhere close to what I have spent my life doing without you spending your life on it as well.
And you'd get a big jump start if you read my book.
(I appologize for the high level of confidence and pride!)
To further support what Mat is saying consider this. I would have to be pretty bad at this whole design process - waveguides, crossover, etc. - if after doing it and refining the design over some five years or more I didn't get something that was better than a novice could do in a shorter period of time. Quite honestly, there is simply no way that you could do as good a crossover as I have done even if you use my waveguides and foam plugs. I have custom tools, a good measurement setup, a not insignificant amount of experince and well, quite honestly, a knowledge level that not many others have.
If you want to "play" with waveguides and crossovers for the fun of learning that's great, really, have a ball. But don't kid yourself that you will get anywhere close to what I have spent my life doing without you spending your life on it as well.
And you'd get a big jump start if you read my book.
(I appologize for the high level of confidence and pride!)
I respect your confidence and pride, I have read all your papers, etc too. I have not purchased your book, I should to get it to also get the measuring software.
Of course your post is not something I havent read from experts over the past several years. The single biggest reason why I use active crossovers is because I can get something running that is really good without going through the headaches of the crossover design which is the most important of the whole build.
besides, that...100+ econo waveguide fans can't be completely wrong, can they ?
Of course your post is not something I havent read from experts over the past several years. The single biggest reason why I use active crossovers is because I can get something running that is really good without going through the headaches of the crossover design which is the most important of the whole build.
besides, that...100+ econo waveguide fans can't be completely wrong, can they ?
gedlee said:Well there are "experts" and there are "experts". And all the completely satisfied Summa owners can't be wrong either
I don't sell measurement software only simulation software. My custom crossover software is what is called "hardware in the loop" and I don't sell it.
I am not rich by any means, but I spent a fair chunk of change for a pair of Summas.
Why did I do this?
Of course the main reason is that they sound good.
But there's a second and more insidious reason
I've been buying audio/video gear for a decade or so, and at first I would buy good, inexpensive gear. For instance, the first pair of speakers that I bought were a set of JBL monitors that received a good review from Corey Greenberg in Stereophile. I bought them from Best Buy, and paid $300 for them IIRC. When I started building my own speakers, I put the JBLs on Ebay... and they sold for more than I paid for them!
This was a bit unexpected! I mean, they were cheap speakers I bought from Best Buy... I thought I'd be lucky to get $100 for them.
Over the years, I've consistently noticed this. If you buy an amp or a set of speakers for a fair price, and they're no longer available, you can re-sell them on Ebay or Craigslist for more than you paid for them.
To make a long story short, one of the reasons that I purchased the Summas is that I'm confident they'll hold their value for years or decades. In fact I'll bet they'll be worth more than I paid for them in five or ten years.
In fact it's downright odd that people will spend $25,000 on a car that's worth $5,000 after ten years, but they balk at spending $5000 for a pair of speakers that will be worth about the same. Maybe I am unusual, but I spend more time listening to music than I spend in my car.
Just something to consider, if you're putting off the purchase of these, or waiting for a cheaper option. These speakers may be downright collectible in five or ten years.
Just an interesting story about collectability of oddities. I have a small (3) guitar collection. All are highly unusual and rare, one being a gibson ES-125 with an unusual pickup arrangement for it's particular vintage, a Chandler Telepathic one off custom made for me, and a Phiga. All of these instruments are worth more than double what I paid for them, but most people balk at what I did pay. But as you said, most wouldn't think twice about spending 25,000 on a car (My 5 year old WRX did almost that exact trend in value).
I like that idea!
I once bought a used Hasselblad. Used it for five years and sold it for exactly what I paid for it. That was a nice investment. Wish I had sold ALL my uber expensive 35mm and 120 cameras and equipment at that same time. It's all worthless now. Zeiss lenses, everything. That stuff can't touch even a mid-line Nikon of today. And todays lenses - wow the wonderers of plastic: lighter, better, castable non-spherical shapes, resolution to die for.
I once bought a used Hasselblad. Used it for five years and sold it for exactly what I paid for it. That was a nice investment. Wish I had sold ALL my uber expensive 35mm and 120 cameras and equipment at that same time. It's all worthless now. Zeiss lenses, everything. That stuff can't touch even a mid-line Nikon of today. And todays lenses - wow the wonderers of plastic: lighter, better, castable non-spherical shapes, resolution to die for.
gedlee said:
Dr. Geddes,
I hate to take us off topic but it won't be the first time this thread has wandered a bit
I am curious about your custom XO software. I am familiar with the term "hardware in the loop" but wonder how you are using the term related to XO design.
Are you referring to a XO emulator which takes the XO transfer function and emulates that using a multichannel soundcard hooked to a multi-channel amp? For example this type of functionality is in SoundEasy and LspCad.
Thanks and regards,
Dennis
Patrick Bateman said:
If you bought a house in 2008, you'd probably be about about $25,000 poorer.
If you bought a car in 2008, you'd probably be about $5000 poorer.
If you invested $10,000 dollars in the stock market, you'd be about $4000 poorer.
Therefore, we should all invest in Summas
Check.
Check.
Check. Times a unfortunate multiplier.
Only good investments were guitars, audio gear, guns and ammo. On the bright side, I unloaded my "high end" amps/preamps/sources right before the bottom fell out.
I used to say I would never go Digital, finally invested in a Nikon D70S, the first digital I thought was any good at a price I could afford, and I would never go back. I'm not one for bells and whistles, but the new vibration reduction lenses are, in my opinion, a godsend to photographers. You used to have to be Buddha himself to use a 300+mm lens freehand and get a good detailed picture. A Parkinson patient could use one today free hand.
I took all of these below with my Nikon, and I have to say, that type of lighting used to really throw off the older digital cameras.
All of these with the exception of the last photo was shot in raw format, all are not a huge pixel rate (6.1), but I have and can blow these up to standard poster sizes and have them look just as good as standard film would. Just like with 35mm film, even at very low iso settings I can't make a billboard, but images with dimensions in excess of 36" can still look passable.
just a quick copyright note, these are my pictures that I took and I ask they not be reproduced, printed, or used without my express written permission. I show these in juried art events and sell printed versions.
I took all of these below with my Nikon, and I have to say, that type of lighting used to really throw off the older digital cameras.
All of these with the exception of the last photo was shot in raw format, all are not a huge pixel rate (6.1), but I have and can blow these up to standard poster sizes and have them look just as good as standard film would. Just like with 35mm film, even at very low iso settings I can't make a billboard, but images with dimensions in excess of 36" can still look passable.
just a quick copyright note, these are my pictures that I took and I ask they not be reproduced, printed, or used without my express written permission. I show these in juried art events and sell printed versions.
Well this is a DIY forum so I would suspect most here are building their own speakers. Not promoting the sales of speakers
If I wanted to buy speakers I would just buy JBL K2s and be done with it all but where is the fun in that. I build speakers just for kicks....I have more speakers then room anyways now.
If I wanted to buy speakers I would just buy JBL K2s and be done with it all but where is the fun in that. I build speakers just for kicks....I have more speakers then room anyways now.
djarchow said:Dr. Geddes,
I hate to take us off topic but it won't be the first time this thread has wandered a bit
I am curious about your custom XO software. I am familiar with the term "hardware in the loop" but wonder how you are using the term related to XO design.
Are you referring to a XO emulator which takes the XO transfer function and emulates that using a multichannel soundcard hooked to a multi-channel amp? For example this type of functionality is in SoundEasy and LspCad.
Thanks and regards,
Dennis
Hi Dennis
I use measured polar responses in a full polar map simulation of how the crossover components will affect the sound field. Its not an auralization, but way more advanced than a simulation of the axial response. I find its accuracy to be about 1/2 dB, which is very good for a full polar response.
What all the other programs do is a single direction with auralization, which is pretty meaningless.
