Fatmarley
"It appears my intelligence circuits have melted"
I've not long finished a speaker project, but with lots of time to think and boredom setting in, I'm already thinking about my next build.
The last speakers I built (10" 2-way with Eminence pro-audio woofers) worked out so well (sound quality wise at least) that I now hope I'm qualified enough to give something back to PFM. So why not just give details of the last build? Two reasons - It wouldn't be easy to recreate the curved sides, and I had to push the tweeter very low to achieve the frequency response I wanted, and as a result they probably won't go very loud playing certain tracks that have a lot of energy around 500hz to 800hz (they seem fine at the volumes I play at though)- The Wavecore TWO30WA12 is an amazing tweeter!
Big woofers / midbass drivers just sound more real to me. It's the same with compression drivers. Soft dome tweeters just don't have the same dynamics and energy of a good CD. The biggest I've built so far is with a 10" woofer... But It's now time to up the game!
First thoughts were about designing a budget 15" 3-way In a large 100 to 150ltr Sealed box, with the 15" Peerless FSL-1520R02-08 bass driver. It can be had for an amazingly low price of only £32! The Peerless FSL-0818R01-08 8" midrange is only £21, the Monacor DT-300 tweeter £22, and it's WG-300 Waveguide is about £8. Looking at simulations this would give a similar bass response to the old JPW AP3 (28ltr Sealed 8" woofer), but with a 15" you're really going to feel that punch. Problem is, I'm the one who's going to have to live with these speakers and I know I'd soon be thinking of upgrading them to higher quality drivers - so the current thinking is a much more upmarket 15" 2-way in a smaller cabinet of around 90ltrs. Baffle dimensions roughly - 16" x 36"
Due to the size, these speakers are obviously going to weigh a ton if I build them out of MDF. This will make dragging them outside for measurements very difficult, so I think I'll have to build them out of tile backing, foam-core like my current ones. They'll still be heavy because of the drivers though and the biggest challenge will be the large difference in acoustic centres (crossover will be difficult to get good phase alignment)... Not sure how I'm going to make them WAF friendly though. Maybe some laminate like the stuff they use for kitchen worktop edging? Or faux leather?
Drivers:
For the big 15" woofer - I'm thinking about the Beyma 15P80FeN, partly because I can achieve an f3 of 47hz in a not unreasonably sized 80ltr enclosure (extended bass shelf), but also because of the very a powerful motor (Qes 0.19!) reasonable QMS, and relatively low MMS, so should sound clean, fast and dynamic with serious punch. CMS is a bit higher than most pro audio drivers (that's a good thing) so hopefully it'll sound ok at low volume (it's no Tannoy though
).
For the tweeter - I'm looking at the 18Sound ND1460A compression driver on the 18Sound XT1464 horn - mainly because I've seen independent measurements and it looks quite smooth and extended, and also because it's capable of crossing very low (around 700hz should be fine). According to what I've read, these aluminium drivers are smoother sounding than titanium. Unfortunately, most drivers of this size that have plastic diaphragms seem to roll off early (At least all the FaitalPro ones I looked at do). If I find I'm not happy with the highest frequencies, I could low-pass the ND1460A and add a super tweeter on top of the cabinet. I'm not expecting anyone to rush out and spend £900+ on drivers etc when they don't know what they sound like (I wouldn't trust me either). But maybe if someone wants to come and listen, or if there's an enthusiast show somewhere, perhaps I'll take them. This is all assuming they turn out to my liking obviously... Done properly, I can't see them being anything less than bloody impressive. Doubt the girlfriend will be happy though
I often think up speaker designs and then change my mind, so this isn't set in concrete, just my rambling thoughts...
The last speakers I built (10" 2-way with Eminence pro-audio woofers) worked out so well (sound quality wise at least) that I now hope I'm qualified enough to give something back to PFM. So why not just give details of the last build? Two reasons - It wouldn't be easy to recreate the curved sides, and I had to push the tweeter very low to achieve the frequency response I wanted, and as a result they probably won't go very loud playing certain tracks that have a lot of energy around 500hz to 800hz (they seem fine at the volumes I play at though)- The Wavecore TWO30WA12 is an amazing tweeter!
Big woofers / midbass drivers just sound more real to me. It's the same with compression drivers. Soft dome tweeters just don't have the same dynamics and energy of a good CD. The biggest I've built so far is with a 10" woofer... But It's now time to up the game!
First thoughts were about designing a budget 15" 3-way In a large 100 to 150ltr Sealed box, with the 15" Peerless FSL-1520R02-08 bass driver. It can be had for an amazingly low price of only £32! The Peerless FSL-0818R01-08 8" midrange is only £21, the Monacor DT-300 tweeter £22, and it's WG-300 Waveguide is about £8. Looking at simulations this would give a similar bass response to the old JPW AP3 (28ltr Sealed 8" woofer), but with a 15" you're really going to feel that punch. Problem is, I'm the one who's going to have to live with these speakers and I know I'd soon be thinking of upgrading them to higher quality drivers - so the current thinking is a much more upmarket 15" 2-way in a smaller cabinet of around 90ltrs. Baffle dimensions roughly - 16" x 36"
Due to the size, these speakers are obviously going to weigh a ton if I build them out of MDF. This will make dragging them outside for measurements very difficult, so I think I'll have to build them out of tile backing, foam-core like my current ones. They'll still be heavy because of the drivers though and the biggest challenge will be the large difference in acoustic centres (crossover will be difficult to get good phase alignment)... Not sure how I'm going to make them WAF friendly though. Maybe some laminate like the stuff they use for kitchen worktop edging? Or faux leather?
Drivers:
For the big 15" woofer - I'm thinking about the Beyma 15P80FeN, partly because I can achieve an f3 of 47hz in a not unreasonably sized 80ltr enclosure (extended bass shelf), but also because of the very a powerful motor (Qes 0.19!) reasonable QMS, and relatively low MMS, so should sound clean, fast and dynamic with serious punch. CMS is a bit higher than most pro audio drivers (that's a good thing) so hopefully it'll sound ok at low volume (it's no Tannoy though
).For the tweeter - I'm looking at the 18Sound ND1460A compression driver on the 18Sound XT1464 horn - mainly because I've seen independent measurements and it looks quite smooth and extended, and also because it's capable of crossing very low (around 700hz should be fine). According to what I've read, these aluminium drivers are smoother sounding than titanium. Unfortunately, most drivers of this size that have plastic diaphragms seem to roll off early (At least all the FaitalPro ones I looked at do). If I find I'm not happy with the highest frequencies, I could low-pass the ND1460A and add a super tweeter on top of the cabinet. I'm not expecting anyone to rush out and spend £900+ on drivers etc when they don't know what they sound like (I wouldn't trust me either). But maybe if someone wants to come and listen, or if there's an enthusiast show somewhere, perhaps I'll take them. This is all assuming they turn out to my liking obviously... Done properly, I can't see them being anything less than bloody impressive. Doubt the girlfriend will be happy though
I often think up speaker designs and then change my mind, so this isn't set in concrete, just my rambling thoughts...
