Poultrygeist
Lunatic Member
Spiral horns are also on my short list.
I've built or modified many loudspeakers over the years. The initial principle was to take a pair of speakers that I liked and then work out why the good bits are good and why the bad bits are bad. Then I would modify them by such things as changing drivers and remaking crossovers until I got them to be the best I could make them. This wasn't just done at random as the important thing to me was to know why they sound the way they do. Over time I went down the road of designing and building systems from scratch. I've lived and breathed calculations from Thiel-Small, reflex porting, box resonance and transmission lines. The designs from Troels Gravesen are fabulous, as are those from John "Zaph" Krutke and it's interesting to me how those designs were developed.
I'm now into fully active systems with a transmission line bass cabinet topped off with a separate pressure vented mid/tweeter cabinet, all very heavily built. I've had a lot of positive comments regarding the sound that these units can produce. The trouble is that people just see the speakers and don't realise that they are just one element of an active system where everything has to be tuned to form the complete system.
I agree that it's difficult to put a value to things that are home built and that invariably the important thing is that it doesn't really matter. This is a hobby after all. If I were to try to quantify the cost of materials plus probably hundreds of hours of my time then these speakers would cost many thousands of pounds. The thing is that I can't compare them to commercial units anyway because they are unique.
I might add - for a bit of detail- that the side view was quite early in construction and there are a lot of extra fillets that were added after this pic was taken. Also the outer cabinet layers are missing in this pic. Cabinets are between 30mm and 48mm thick. The 2 cutouts in the back are now covered by 3mm thick damped steel plates to give access to the line to alter the stuffing for tuning purposes. I might add that the TL line calculations and CAD design took weeks to get right. The upper units have 2 40mm rear ports. These are not tuned as reflex ports though. There is a divider in the cabinet and the ports are there purely to release pressure/vacuum when the drivers are working. This allows the mids to operate almost like open baffle drivers with the rear energy absorbed, but with no pressurisation as you would have with true infinite baffle speakers. I am also contemplating reworking them to give a stepped baffle. The Vifa H26TG-35-06 Tweeters have been replaced with SEAS 27TBFC/G H1212 Alloy domes. The mid and Bass units are Peerless Nomes 164 and 205 units. The bass extends to 26Hz (-3dB) and will quite happily shake the floor. There are no crossovers as the system is fully active. I had to redesign the support feet as the original cross bars were starting to collapse with the weight. I weighed them once at 38kg each which is quite solid, bearing in mind that they are only 11" wide. The second pair of speakers were a previous incarnation using the same drivers, but in a reflex loaded cabinet. They sounded pretty good too, but they were a bit bass heavy.
People usually underestimate the time and effort involved in speaker building. And it isn't cheap either.
Because I'm sometimes childishly stupid, I have a hankering for something like this.
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Yes I kind of agree. Before starting any kind of DIY project a number of things need to be considered.
Why do I want to do this?
1. Is it to save money? (then you are probably going to regret it).
2. Am I building something I could buy?
3. Am I building something that nobody makes?
4. Am I doing this purely because I am interested and it is my hobby?
5. Do I have the knowledge and resources to do this?
6. Do I have the time to do this?
7. Am I modifying something, adapting something or designing from scratch?
In my case, points 3 and 4 are the main drivers with 5 & 6 being of additional benefit. Points 1 & 2 are of little interest to me in this context, although I do keep an interest on how manufacturers design things - no point in redesigning the wheel.