The more I read and learn, the more I realize I don't know... I'm looking at building a new set of speakers, which feels like a major undertaking for how little experience I have in this space. I do not have an EE background, and so I feel like I'm constantly doing a ton of electrical and physics catch up just to start learning about drivers and crossover design. I don't have any testing equipment, and I'm unlikely to be able to buy any any time soon. I have decent woodworking and finishing skills, so the cabinets themselves are a non-issue. I have built speakers before: I'm still listening to a set of Jeff Bagby's RS180 MTMs I built in 2010ish. But after that I somehow completely shelved my interest, and am only just getting back to it now...
A few days ago I felt committed to a single woofer, if for no other reason than WAF. Paul K has been extremely helpful in designing something like an MLTL enclosure for a single Seas ER18 woofer.
But now I'm considering an MTM or TMM. One design I'm considering is something like Paul K/Dennis Murphy's ER18 MTM, but with the Sea DXT tweeter instead of the Fountek ribbon. Another way of looking at this is to say I'm considering Mark K's ER18/DXT speaker but with another woofer. I'm working my way through the "designing crossovers without testing equipment" thread, but it's a long one...and again, my EE understanding is what it is, and it is somewhat limited.
Can someone make my life easier and put me on the right track? Should I be looking at redefining the filters on the MTM design to suit a different tweeter, or adding a woofer to Mark K's design? Or would I start from scratch in designing a new filter? I would like a bit of a challenge, but I'm currently feeling a little too challenged. 😉
A few days ago I felt committed to a single woofer, if for no other reason than WAF. Paul K has been extremely helpful in designing something like an MLTL enclosure for a single Seas ER18 woofer.
But now I'm considering an MTM or TMM. One design I'm considering is something like Paul K/Dennis Murphy's ER18 MTM, but with the Sea DXT tweeter instead of the Fountek ribbon. Another way of looking at this is to say I'm considering Mark K's ER18/DXT speaker but with another woofer. I'm working my way through the "designing crossovers without testing equipment" thread, but it's a long one...and again, my EE understanding is what it is, and it is somewhat limited.
Can someone make my life easier and put me on the right track? Should I be looking at redefining the filters on the MTM design to suit a different tweeter, or adding a woofer to Mark K's design? Or would I start from scratch in designing a new filter? I would like a bit of a challenge, but I'm currently feeling a little too challenged. 😉
What drew you to these 2 designs? What are your goals? What are your limits (how big?)
I would start with some constraints - such as your current room, how big you can go, how loud and how low, what amplification you have.
Edit - last and not least, budget on drivers and crossover parts (assuming you go passive and your build / cabinet costs you consider "free")
I would start with some constraints - such as your current room, how big you can go, how loud and how low, what amplification you have.
Edit - last and not least, budget on drivers and crossover parts (assuming you go passive and your build / cabinet costs you consider "free")
The room is about 250 sq ft with 10 ft ceilings.
I'm not sure what drew me to these designs. I would like small towers rather stand-mounted speakers, I think just for aesthetic simplicity. Cost is somewhat of a concern, but isn't make-or-break. I think I started looking at SR71s and got kinda stuck on the ER18 woofer, and then read more into Mark K's design and the superiority of the DXT tweeter. Then I found Paul K's MTM, but I'm not nuts about CAN$650 worth of ribbon tweeters... I'd like to keep the whole project under $1k unless there's really a reason why this is better than that, etc.
I'm not sure what drew me to these designs. I would like small towers rather stand-mounted speakers, I think just for aesthetic simplicity. Cost is somewhat of a concern, but isn't make-or-break. I think I started looking at SR71s and got kinda stuck on the ER18 woofer, and then read more into Mark K's design and the superiority of the DXT tweeter. Then I found Paul K's MTM, but I'm not nuts about CAN$650 worth of ribbon tweeters... I'd like to keep the whole project under $1k unless there's really a reason why this is better than that, etc.
No disrespect to those designers or designs, but they are older. Being in Canada, I don't know what local supply options you have for drivers vs. shipping and import taxes.
SB Acoustics, specifically their Satori line have some very nice drivers. There are lots of options (almost too many) to choose from. Arguably they beat the drivers mentioned in the designs above. If you want to build someone elses, plenty of SBA designs out there. IF not, measurement data is available and support.
If you are swapping out driver X for driver Y in any design, you really are looking at a new design. Invariably everything needs adjusting. you may get away with the same topology on the driver(s) you are not replacing, but the component values will need to change to ensure phase alignment with your new driver(s)
If you cannot measure, then design by simulation on manufacturer curves is possible with some limitations. That is - you can design "simple" speakers this way - those without custom waveguides or horns, flat or stepped baffle with conventional dome, ribbon or cone drivers, where the source measurements are reliable in known measurement conditions.
SB Acoustics, specifically their Satori line have some very nice drivers. There are lots of options (almost too many) to choose from. Arguably they beat the drivers mentioned in the designs above. If you want to build someone elses, plenty of SBA designs out there. IF not, measurement data is available and support.
If you are swapping out driver X for driver Y in any design, you really are looking at a new design. Invariably everything needs adjusting. you may get away with the same topology on the driver(s) you are not replacing, but the component values will need to change to ensure phase alignment with your new driver(s)
If you cannot measure, then design by simulation on manufacturer curves is possible with some limitations. That is - you can design "simple" speakers this way - those without custom waveguides or horns, flat or stepped baffle with conventional dome, ribbon or cone drivers, where the source measurements are reliable in known measurement conditions.
build something. Learn along the way. Yes, there is lots of theory but practical knowledge gets it done and can only be learned by doing.
From solen.ca you can get the SB17NBAC-8 for slightly more than an ER18. I'd wager the former has lower midrange distortion than the ER18 (but I can't find any comparable tests).
You can't go wrong I think either way. PS: my current mains are all Seas drivers.
You can't go wrong I think either way. PS: my current mains are all Seas drivers.
Designing a 2.5 way can be easier than a 2 way since it separates the baffle step compensation, and allows you to deal with it solely through the extra woofer.. which is then easier to do. This also lets you ignore the baffle step for the other woofer and tweeter focussing directly on the crossover.
Converting a regular 2 way into 2.5 way may be easier than designing an MTM.. however you'd then need to undo the baffle step compensation by lifting the tweeter level and relaxing the woofer cross.
Don't directly compare a conventional MTM with 2.5 way. The D'Appolito MTM configuration is about using both M's in the cross, which is complex. 2.5 way crosses one woofer away lower than the cross.
Converting a regular 2 way into 2.5 way may be easier than designing an MTM.. however you'd then need to undo the baffle step compensation by lifting the tweeter level and relaxing the woofer cross.
Don't directly compare a conventional MTM with 2.5 way. The D'Appolito MTM configuration is about using both M's in the cross, which is complex. 2.5 way crosses one woofer away lower than the cross.
Long narrow is good, wide short is very different, what are dimensions? Which wall are speakers going on, where is listening chair? Are speakers to be away from any wall? What types of music, how many amp watts available?
Measuring is not rocket science. Do you have a PC with a blue line in jack? Instead a little more expensive, do you have a laptop with USB input? Either could run audacity or REW, both free. (USB mikes cause delay issues, I don't recommend them). Do you have a yard that gets quiet at night where you don't have to measure indoors and deal with reflections? I measure from 2 m away so I don't need a omni mike. ( I listen from 11' away and am not interested in the near field). I use a $60 used mixer to provide phantom power. I use a $29 mike that does not cover 15000-20000 hz, which I can't hear. Where does your hearing stop? Top 2 octaves cost. If you intend to sit 3' from the speakers, you need a $120 omni mike like parts-express or behringer. PE ships by UPS, not good for Canadians because of the customs loan fee.
AllenB always brings up BSC right away which is important if you are locating your speakers in the middle of the room or on front of a stage. 50% of us locate speakers aganst the front wall, which provides 3 db bass boost for no money or amp watts. In a bookshelf 6" from wall deosn't help boost bass, but you said towers, not bookshelf speakers. On a desk speakers need BSC too.
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Locating freestanding box speakers near walls can produce peaks and dips, and while they can average to a partial compensation, it's not automatically a satisfactory alternative. On the other hand, if a person can design a way around this.. then they may well not need the current level of assistance.
I you want to modify or add another ER18 in 2.5 way configuration to the Mark K design, I'm happy to help.
I'd say it depends on where you're listening from in relation to the speakers, MTM will likely project better if you're not close
Hey, thanks for all the replies! OK, so no love for the ER18… I didn’t realize drivers like this would be surpassed in fifteen years. I’m used to bikes, where everything is old in 18 months: I had given myself the impression that speakers were pretty much the opposite! 😉
The room is pretty much square, and sunken down two steps from a broad entranceway; it’s almost a three-walled room. It’s full of furniture and lined with books, and is also the room we (and our kids) use for televised entertainment. (We live in an incredibly expensive little mountain paradise, and the house feels big relative to a lot of properties in our absurd “price range,” but it isn’t really.)
Because it’s also used for TV and kids and stuff, space is sorta at a premium: I don’t want monoliths, and I don’t have space for the stack of electronics I see in a lot of listening-room pictures. I’m using a decent Marantz HT amp, not sure exactly what, probably 50w per channel. We have a centre channel (no surrounds), and I’m not averse to a sub, but these speakers will do 70/30 music/HT mains.
I never really sit close to the speakers, or right between them, and often use them to “fill” other nearby rooms, including the kitchen, where I spend most of my time (stay-at-home dad). Obviously, off-axis performance is really important. And given that my daughters are nearly teenagers, they ought to be able to play kinda loud (not concert volume, but they can’t distort when my kids want to dance).
All that is to say… I’m open to suggestions. I would love to build something like three-way Kairos/Kalasans, but I don’t think I have the space, nor do I think I can justify spending bike money on drivers. (It’s $ki-racing season! 🤪)
Some of my inclinations are probably purely emotional: I’ve got an all-metal driver set up currently in the RS180/RS28A MTMs, and I think I would like to try paper, carbon fibre, etc. woofers, and some other style of tweeter. Unless anyone knows another source in Canada, I’ll be buying parts from SoLen. And I’d like to move upmarket a little bit from the Dayton parts, whether that makes any sense or not. And I’m somewhat inclined toward European-manufactured drivers…again, maybe this makes no sense?
Finally, I would love to design my own crossovers, but I don’t have money to experiment with, I don’t have testing equipment or software, and I’m profoundly intimidated by what I don’t know about acoustics and EE. I’m more confident inside an automatic watch. Thanks again for the help!
The room is pretty much square, and sunken down two steps from a broad entranceway; it’s almost a three-walled room. It’s full of furniture and lined with books, and is also the room we (and our kids) use for televised entertainment. (We live in an incredibly expensive little mountain paradise, and the house feels big relative to a lot of properties in our absurd “price range,” but it isn’t really.)
Because it’s also used for TV and kids and stuff, space is sorta at a premium: I don’t want monoliths, and I don’t have space for the stack of electronics I see in a lot of listening-room pictures. I’m using a decent Marantz HT amp, not sure exactly what, probably 50w per channel. We have a centre channel (no surrounds), and I’m not averse to a sub, but these speakers will do 70/30 music/HT mains.
I never really sit close to the speakers, or right between them, and often use them to “fill” other nearby rooms, including the kitchen, where I spend most of my time (stay-at-home dad). Obviously, off-axis performance is really important. And given that my daughters are nearly teenagers, they ought to be able to play kinda loud (not concert volume, but they can’t distort when my kids want to dance).
All that is to say… I’m open to suggestions. I would love to build something like three-way Kairos/Kalasans, but I don’t think I have the space, nor do I think I can justify spending bike money on drivers. (It’s $ki-racing season! 🤪)
Some of my inclinations are probably purely emotional: I’ve got an all-metal driver set up currently in the RS180/RS28A MTMs, and I think I would like to try paper, carbon fibre, etc. woofers, and some other style of tweeter. Unless anyone knows another source in Canada, I’ll be buying parts from SoLen. And I’d like to move upmarket a little bit from the Dayton parts, whether that makes any sense or not. And I’m somewhat inclined toward European-manufactured drivers…again, maybe this makes no sense?
Finally, I would love to design my own crossovers, but I don’t have money to experiment with, I don’t have testing equipment or software, and I’m profoundly intimidated by what I don’t know about acoustics and EE. I’m more confident inside an automatic watch. Thanks again for the help!
All things considered, speakers designed for up in the ceiling corners like in a bar, etc., is your best bet.
Okay, far field (2.5 m up), walls dirty so no annoying rellections, walk around so wide dispersion, project into next room up stairs. 50 w/ch. Party volume sometimes, maybe 110 db.
2 way crossovers are lot easier than 3 way, and I find 15"+1.4" CD horn covers my whole 14'wx33'long room with 1 watt if no boom box cars driving by & nobody talking. 54 to 17 khz +- 3 db and my against wall placement makes 26-54 hz audible. Copy of pispeakers.com 4 pi, or econowave https://www.diyaudio.com/community/threads/econowave-style-15.400662/
and
https://www.diyaudio.com/community/threads/2023-econowave.396586/
Pi has response charts up to 90 deg off axis. My SP2(2004) are 6 db down at 90 deg off axis.
If you can put these on stands or poles (I have poles) 2 m apart, the horn can be tilted down a bit and cover the whole room over the clutter. My SP2(2004) are 6' off the ground. I have the 1.5" tall CS800s amp under the couch (has a fan), CD players don't take much room, nor a MP3 pod or cell phone. A $14 8 to 2 RCA jack TV switch can switch sources, Or I use a mixer which gives more control including bass & treble boost & cut. Individual gain controls for different sources. I use PV8 but PV6 could work too. Alesis & allen&heath make mixers I respect. Used ones, like I buy, the master volume control usually need replacement. You'll need a $80 used graphic equalizer to kill the room reflections at 25'. Or build it into your passive crossover.
a 12" woofer can work but takes a few more watts than a 15". 8": woofers can work but takes a tuned organ pipe. I think woofers that don't hardly move at home volume have a chance of producing lower harmonic distortion than smaller ones that do. My Peaveys have HD 25 db down for 2nd & 3rd harmonic, charted in the datasheet. I bought them because they sound better than anything I've heard in this flyover town, including the meyersounds down at the ballet.
B&C Beyma & Fatal make popular European drivers. I'm building with eminence Deltapro15a (15") & N314T-8 CD, (1.4") although you can often get Peavey RX22 CD (1.4") + horn used on ebay/facebook/gumtree for $150 the pair delivered. I think a 6 db/octave (one inductor for 1200 hz) woofer treatment could tame the 1300 hz peak the deltapro-15a has plus kill anything above. The RX22 or N314T-8 can both cover 1000-17khz (up to 70 watts RX22, 100 N314T-8) and a simple 12 db/octave filter should protect them below 1000. (series capacitor, parallel inductor, series resistor to pull CD volume down to the 100 db of the woofer). Peavey SP2 makes do with 5 parts in the crossover, 2 inductors, 2 capacitors, 1 tungsten bulb to kill huge bangs from mike drops or cables pulled out. You don't have a mike, but cables can pull out with kids or parties. Big bangs & too much crunch guiltar (square waves) can blow tweeters.
Eminence has a sample box design on the website, i favor the big vented box. Eminence Kappapro-15 is worth a look although the delta has a smoother rising >1000 hz curve that exactly matches the opposite of a single series inductor curve.
Glad you are good at woodwork, I'm having a real problem with it.
MTM & TMM are what you want, more complicated read those threads. Main complication on 2 way, killing internal box reflections with stuffing. Peavey uses an elastomer sheet folded up 5 times.
Happy shopping building & listening.
2 way crossovers are lot easier than 3 way, and I find 15"+1.4" CD horn covers my whole 14'wx33'long room with 1 watt if no boom box cars driving by & nobody talking. 54 to 17 khz +- 3 db and my against wall placement makes 26-54 hz audible. Copy of pispeakers.com 4 pi, or econowave https://www.diyaudio.com/community/threads/econowave-style-15.400662/
and
https://www.diyaudio.com/community/threads/2023-econowave.396586/
Pi has response charts up to 90 deg off axis. My SP2(2004) are 6 db down at 90 deg off axis.
If you can put these on stands or poles (I have poles) 2 m apart, the horn can be tilted down a bit and cover the whole room over the clutter. My SP2(2004) are 6' off the ground. I have the 1.5" tall CS800s amp under the couch (has a fan), CD players don't take much room, nor a MP3 pod or cell phone. A $14 8 to 2 RCA jack TV switch can switch sources, Or I use a mixer which gives more control including bass & treble boost & cut. Individual gain controls for different sources. I use PV8 but PV6 could work too. Alesis & allen&heath make mixers I respect. Used ones, like I buy, the master volume control usually need replacement. You'll need a $80 used graphic equalizer to kill the room reflections at 25'. Or build it into your passive crossover.
a 12" woofer can work but takes a few more watts than a 15". 8": woofers can work but takes a tuned organ pipe. I think woofers that don't hardly move at home volume have a chance of producing lower harmonic distortion than smaller ones that do. My Peaveys have HD 25 db down for 2nd & 3rd harmonic, charted in the datasheet. I bought them because they sound better than anything I've heard in this flyover town, including the meyersounds down at the ballet.
B&C Beyma & Fatal make popular European drivers. I'm building with eminence Deltapro15a (15") & N314T-8 CD, (1.4") although you can often get Peavey RX22 CD (1.4") + horn used on ebay/facebook/gumtree for $150 the pair delivered. I think a 6 db/octave (one inductor for 1200 hz) woofer treatment could tame the 1300 hz peak the deltapro-15a has plus kill anything above. The RX22 or N314T-8 can both cover 1000-17khz (up to 70 watts RX22, 100 N314T-8) and a simple 12 db/octave filter should protect them below 1000. (series capacitor, parallel inductor, series resistor to pull CD volume down to the 100 db of the woofer). Peavey SP2 makes do with 5 parts in the crossover, 2 inductors, 2 capacitors, 1 tungsten bulb to kill huge bangs from mike drops or cables pulled out. You don't have a mike, but cables can pull out with kids or parties. Big bangs & too much crunch guiltar (square waves) can blow tweeters.
Eminence has a sample box design on the website, i favor the big vented box. Eminence Kappapro-15 is worth a look although the delta has a smoother rising >1000 hz curve that exactly matches the opposite of a single series inductor curve.
Glad you are good at woodwork, I'm having a real problem with it.
MTM & TMM are what you want, more complicated read those threads. Main complication on 2 way, killing internal box reflections with stuffing. Peavey uses an elastomer sheet folded up 5 times.
Happy shopping building & listening.
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With only 50w on tap and dance volumes you'll need something sensitive. Up into the high 90s. Problem here with a compression driver and efficient midbass is you'll end up with a wider speaker.
Another option is a tall skinny multidriver option such as curt Campbell's uluwatu
https://speakerdesignworks.com/SB6pakproject_6.html
I am not saying you should build that exact speaker but trying to gauge what style you are leaning toward
Another option is a tall skinny multidriver option such as curt Campbell's uluwatu
https://speakerdesignworks.com/SB6pakproject_6.html
I am not saying you should build that exact speaker but trying to gauge what style you are leaning toward