About 8 years ago I started building a pair of speakers and, well life got in the way; new house, new girlfriend (now wife), another house and a few renos later…and the parts were all still sitting around. I found them all during a post-Christmas cleanup.
The options were: get rid of the stuff or finally finish the project. I figured it was just as much work to sell all the stuff off as to finally build the boxes (ok, maybe not, but it was good justification).
Drivers:
- Tweeters – a pair of original Heil AMT1’s. ~96 dB/ wm
- Mids – two Vifa P13MW-00-08 per side ~89 dB/ wm
- Subs – two scanspeak 23w/4557t00 per side, with matching passive radiators, ~84 dB/ wm
Each are great on their own, but when combining them, the challenge is balancing the efficiencies.
- Tweeters ~96 dB/ wm
- Mids ~88 dB/ wm. Using two raised the efficiency to 91
- Subs ~84 dB/ wm. Using two raised the efficiency to 87. Ok, using 4 per side would even things out better. However that’s a much bigger box and these are ******* expensive!
When I previously tried doing this with a B&K pre-amp, I could never get rid of line noise and a wicked 60hz hum. I finally decided it was the mix of home and pro audio gear that caused grounding issues – and I never figured it out. So I gave up.
I later I decided to go all pro-audio, no mixing of standard and with the grounding natively built right in. So the setup is now as follows:
Music source: an old IBM S50 PC that I’ve been running forever. Its small, quiet, fits normal audio cards and best of all…its already set up!
Software: MediaMonkey. Most of the music is ripped as Windows Lossless, some FLAC, some lower quality. I like that MM will play almost any file type, without converting and it allows me to organize the files the way I want. (Genre\Artist\Album\Filename) The plug ins are great.
Perversely, for all other computer usage, I’ve gone all Apple. Desktop, iPad, iPhone, iPods and couldn’t be happier
But for really playing MUSIC, I have to say that iTunes is a really a total POS, that just can’t deal with at all. It drives me crazy by constantly converting, manipulating files, names etc…. So I’m sticking to the old tried and true.
Audio card: Lynx One. It provides both digital and analog output with XLR outputs. It only runs under Win XP, but hell…Windows has not really improved much since then. Currently its set for analog out. Haven’t figured out the digital out capabilities yet
Tweeter and Mid Amps: Tweeters & mids: Crown D-75 amp. 45w, high quality, rugged, no fuss. Sound very good and are cheap (used)
Sub amp: Crown K2. A workhorse, more power than I can use, excellent damping, no fan. I don’t care about any frequencies above 200 hz, so tonality and most of the other characteristics that are used ot judge amps just don’t matter.
Crossover: Behringer DCX2496. Allows for analog or digital in (haven’t figured out the digital path yet) and 6 analog out. A buddy builds custom analog gear for studios and just roll his eyes at the silliness of using digital crossovers. However, the DCX allows me a ton of flexibility to get all the values worked out. If there really are issues with the sound, then I’ll know the crossover points, gain, EQ and see if he can build that in analog. I can’t see how, for under the $300 that the DCX costs.
Crossover levels and type (Linzwitz, Bessel etc, 12/24/48) can be set independently. Low and high pass filters are easy are easy to set up. Parametric equalizer is built in. Compared to the DBX Driverack the only thing I’m missing is the AutoEQ, but it’s a fraction of the price. I have tried the DBX Driverack PA and can’t honestly say its much better
The DCX has dynamic EQ, so I can boost bass when volumes are low (romantic fireside moods). I rarely turn it up VERY loud.
Conversely, I can set maximum limits to protect the amps / drivers, for when drunken idiots (friends/brothers…) get near the gear. And best of all, I can lock the settings so drunken idiots (friends/brothers…) can’t push buttons while saying “DOH..what does this do????” Guess who blew the last set of amps….
Interconnects: all standard pro-audio XLR’s. Cheap, easy to get and have the signal path inside of the static sleeve for excellent noise suppression and higher signal strength for a lower noise floor. My brother-in-law is a sound engineer. We discussed it for a while and couldn’t find a single reason way unbalanced RCA’s are better. The ends lock into the gear so can’t come loose. Color coded to keep things straight.
Speaker Cables: 6 wire x 13 gauge cable from the amps to the speakers. Neutrik Speakon connectors at the back. I love these. A bit of a pain to assemble and solder, but later its just push/click and its locked in, never come loose by themselves. Strain relief on the cables so the cable won’t pull loose (when someone trips over it or the cleaners move the speakers)
Cabinets: So all that was left was the build the Cabinets. As a budding woodworker, I had all kinds a grandiose plans to build “Reference speakers” that sounded great, looked great and had great WAF. I had TONS of great ideas. All are a ton of work, never came to fruition and hence the stuff sat on the shelf for 7 years. Sound familiar to anyone?
So I scaled it back to….a BOX! 😀
And damn the WAF, she gets to pick the finish color(s).
- All sections were separately modeled in WinISP for the correct volume/tone/cone excursion.
- Dual subs in the bottom, mirrored passive radiators on the back. LOTS of bracing. The F3 should down around 25 hz. Crossover planned for about 125hz
- The mids have their own separate section in the top part. Their F3 is around 100 hz. I expect the subs to take over from there.
- The Heil tweeters will get bolted on top. The recommended crossover values are all over the map, so I will just experiment and see (hear) to what works.
The box is actually 2 layers, lap joins for each layer. The “inside” layer is standard ¾” spruce ply and braced like crazy. The outer layer is ¾” Baltic birch ply laminated on. I found a mix of plywood is the best for damping the resonance (and a bit cheaper). The standard ply is softer and has a lower resonance frequency. The birch is much harder with a much higher resonance.
Questions
1. Are all the drivers connected in phase? I have mids and subs in parallel and will obviously connect them carefully, so the drivers are in parallel. No idea how so check if the sets of drivers are in phase at the crossover points.
2. Setting filters: the DCX gives me options (maybe too many!). if will be easy to set a high pass for the subs to prevent excessive woofer excursion.
I don’t know how pick the filter types: Bessel, Linkwitz Riley, Butterworth, or what slopes.
3. Objective measurements: What tools are available to properly test the speakers (and make adjustments). My ears are pretty good and I’ve listen to enough speakers to be educated. However, I find that I can easily physic myself out and start believing things. So some form of objectivity will really help. I have a condenser mic but have never used it this.
This project has been a long time coming. I had all the components hooked up and playing (on the shelf) last night or testing. The next steps are installing and tuning. I look forward hearing them – finally!
I appreciate any help and suggestions. Thanks
Olaf
The options were: get rid of the stuff or finally finish the project. I figured it was just as much work to sell all the stuff off as to finally build the boxes (ok, maybe not, but it was good justification).
Drivers:
- Tweeters – a pair of original Heil AMT1’s. ~96 dB/ wm
- Mids – two Vifa P13MW-00-08 per side ~89 dB/ wm
- Subs – two scanspeak 23w/4557t00 per side, with matching passive radiators, ~84 dB/ wm
Each are great on their own, but when combining them, the challenge is balancing the efficiencies.
- Tweeters ~96 dB/ wm
- Mids ~88 dB/ wm. Using two raised the efficiency to 91
- Subs ~84 dB/ wm. Using two raised the efficiency to 87. Ok, using 4 per side would even things out better. However that’s a much bigger box and these are ******* expensive!
When I previously tried doing this with a B&K pre-amp, I could never get rid of line noise and a wicked 60hz hum. I finally decided it was the mix of home and pro audio gear that caused grounding issues – and I never figured it out. So I gave up.
I later I decided to go all pro-audio, no mixing of standard and with the grounding natively built right in. So the setup is now as follows:
Music source: an old IBM S50 PC that I’ve been running forever. Its small, quiet, fits normal audio cards and best of all…its already set up!
Software: MediaMonkey. Most of the music is ripped as Windows Lossless, some FLAC, some lower quality. I like that MM will play almost any file type, without converting and it allows me to organize the files the way I want. (Genre\Artist\Album\Filename) The plug ins are great.
Perversely, for all other computer usage, I’ve gone all Apple. Desktop, iPad, iPhone, iPods and couldn’t be happier
But for really playing MUSIC, I have to say that iTunes is a really a total POS, that just can’t deal with at all. It drives me crazy by constantly converting, manipulating files, names etc…. So I’m sticking to the old tried and true.
Audio card: Lynx One. It provides both digital and analog output with XLR outputs. It only runs under Win XP, but hell…Windows has not really improved much since then. Currently its set for analog out. Haven’t figured out the digital out capabilities yet
Tweeter and Mid Amps: Tweeters & mids: Crown D-75 amp. 45w, high quality, rugged, no fuss. Sound very good and are cheap (used)
Sub amp: Crown K2. A workhorse, more power than I can use, excellent damping, no fan. I don’t care about any frequencies above 200 hz, so tonality and most of the other characteristics that are used ot judge amps just don’t matter.
Crossover: Behringer DCX2496. Allows for analog or digital in (haven’t figured out the digital path yet) and 6 analog out. A buddy builds custom analog gear for studios and just roll his eyes at the silliness of using digital crossovers. However, the DCX allows me a ton of flexibility to get all the values worked out. If there really are issues with the sound, then I’ll know the crossover points, gain, EQ and see if he can build that in analog. I can’t see how, for under the $300 that the DCX costs.
Crossover levels and type (Linzwitz, Bessel etc, 12/24/48) can be set independently. Low and high pass filters are easy are easy to set up. Parametric equalizer is built in. Compared to the DBX Driverack the only thing I’m missing is the AutoEQ, but it’s a fraction of the price. I have tried the DBX Driverack PA and can’t honestly say its much better
The DCX has dynamic EQ, so I can boost bass when volumes are low (romantic fireside moods). I rarely turn it up VERY loud.
Conversely, I can set maximum limits to protect the amps / drivers, for when drunken idiots (friends/brothers…) get near the gear. And best of all, I can lock the settings so drunken idiots (friends/brothers…) can’t push buttons while saying “DOH..what does this do????” Guess who blew the last set of amps….
Interconnects: all standard pro-audio XLR’s. Cheap, easy to get and have the signal path inside of the static sleeve for excellent noise suppression and higher signal strength for a lower noise floor. My brother-in-law is a sound engineer. We discussed it for a while and couldn’t find a single reason way unbalanced RCA’s are better. The ends lock into the gear so can’t come loose. Color coded to keep things straight.
Speaker Cables: 6 wire x 13 gauge cable from the amps to the speakers. Neutrik Speakon connectors at the back. I love these. A bit of a pain to assemble and solder, but later its just push/click and its locked in, never come loose by themselves. Strain relief on the cables so the cable won’t pull loose (when someone trips over it or the cleaners move the speakers)
Cabinets: So all that was left was the build the Cabinets. As a budding woodworker, I had all kinds a grandiose plans to build “Reference speakers” that sounded great, looked great and had great WAF. I had TONS of great ideas. All are a ton of work, never came to fruition and hence the stuff sat on the shelf for 7 years. Sound familiar to anyone?
So I scaled it back to….a BOX! 😀
And damn the WAF, she gets to pick the finish color(s).
- All sections were separately modeled in WinISP for the correct volume/tone/cone excursion.
- Dual subs in the bottom, mirrored passive radiators on the back. LOTS of bracing. The F3 should down around 25 hz. Crossover planned for about 125hz
- The mids have their own separate section in the top part. Their F3 is around 100 hz. I expect the subs to take over from there.
- The Heil tweeters will get bolted on top. The recommended crossover values are all over the map, so I will just experiment and see (hear) to what works.
The box is actually 2 layers, lap joins for each layer. The “inside” layer is standard ¾” spruce ply and braced like crazy. The outer layer is ¾” Baltic birch ply laminated on. I found a mix of plywood is the best for damping the resonance (and a bit cheaper). The standard ply is softer and has a lower resonance frequency. The birch is much harder with a much higher resonance.
Questions
1. Are all the drivers connected in phase? I have mids and subs in parallel and will obviously connect them carefully, so the drivers are in parallel. No idea how so check if the sets of drivers are in phase at the crossover points.
2. Setting filters: the DCX gives me options (maybe too many!). if will be easy to set a high pass for the subs to prevent excessive woofer excursion.
I don’t know how pick the filter types: Bessel, Linkwitz Riley, Butterworth, or what slopes.
3. Objective measurements: What tools are available to properly test the speakers (and make adjustments). My ears are pretty good and I’ve listen to enough speakers to be educated. However, I find that I can easily physic myself out and start believing things. So some form of objectivity will really help. I have a condenser mic but have never used it this.
This project has been a long time coming. I had all the components hooked up and playing (on the shelf) last night or testing. The next steps are installing and tuning. I look forward hearing them – finally!
I appreciate any help and suggestions. Thanks
Olaf
some ideas FYI
Very happy to be the first reply.
Very happy I have been living in Canada for years, still love the place but not the cold.
I had the same mid and woofer as yours once, changed the woofer to 12" but still keep the mid.
At one time I was thinking of building a speaker like B&W 802D and got most of the do able ideas but just too much work. If you want I can share some and hope you can get it done.
now I am running biamp but still thinking about active crossover just like your idea.
Very happy to be the first reply.
Very happy I have been living in Canada for years, still love the place but not the cold.
I had the same mid and woofer as yours once, changed the woofer to 12" but still keep the mid.
At one time I was thinking of building a speaker like B&W 802D and got most of the do able ideas but just too much work. If you want I can share some and hope you can get it done.
now I am running biamp but still thinking about active crossover just like your idea.
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Okay, this is a big 'un.
Set off with 24dB Butterworth high-pass around 5Hz lower than your passive radiator tuning frequency, on the subwoofer output. I'd then recommend 4th order (24dB/octave) Linkwitz-Riley crossovers on everything else.
Use the time-alignment feature to align phases around the crossover, and try to pick frequencies where there'll be plenty of overlap between the drivers. That way, the crossovers will swamp anything the driver is doing in terms of rolloff, giving you electrical slope = acoustic slope.
2 ways to set relative levels of drivers...
A) - dial back the gain controls on the amps. Noise performance would (I suspect) improve slightly, and you're making sure the DCX is running at the highest bitrates possible throughout. Problem is that people can mess with amplifier volume controls, rendering any careful setting of limiters etc useless.
B) - run all amps wide open, and alter the gains on each output of the DCX. That's what we do in the PA world, but slight background hiss is of very little concern. Limiters etc work exactly as you've set them.
Matching efficiencies is no problem with something like a DCX.
Chris
Set off with 24dB Butterworth high-pass around 5Hz lower than your passive radiator tuning frequency, on the subwoofer output. I'd then recommend 4th order (24dB/octave) Linkwitz-Riley crossovers on everything else.
Use the time-alignment feature to align phases around the crossover, and try to pick frequencies where there'll be plenty of overlap between the drivers. That way, the crossovers will swamp anything the driver is doing in terms of rolloff, giving you electrical slope = acoustic slope.
2 ways to set relative levels of drivers...
A) - dial back the gain controls on the amps. Noise performance would (I suspect) improve slightly, and you're making sure the DCX is running at the highest bitrates possible throughout. Problem is that people can mess with amplifier volume controls, rendering any careful setting of limiters etc useless.
B) - run all amps wide open, and alter the gains on each output of the DCX. That's what we do in the PA world, but slight background hiss is of very little concern. Limiters etc work exactly as you've set them.
Matching efficiencies is no problem with something like a DCX.
Chris
Apart the fact that the sub is 84 dB at 2.83V (and not 1W), connecting 2 in parallel gives roughly 90 dB, but then you are driving a 2 Ohm load. Is your amp able to do that?
I never used a digital crossover, so I don't know if it is able to deal with the baffle step effect. You need to address this effect because it is impossible to mask it with a wise choice of the crossover point between woofer and mid. I say so because using a true sub you are limited in a crossover point well below the baffle step frequency.
Ralf
Really? Not this year I guess. 🙂
It finally got warm enough to wash the car - exciting times!
But back to -30 C tomorrow.
One reason this project has been on hold is that I'm doing the work in the basement. Fully finished, but still bloody cold.
Olaf
Thanks for all the responses
One speaker is functional, the other still in the works.
Overall, without tuning, it already sounds pretty decent.
Full base, but not boomy. The sub are wire in parallel. The Crown K2 will be able to play 2 oms, its rated for that. Since the drivers will only take about 225 W and the amp can put out far more
Mids are very clear, maybe a bit too forward.
The highs are very clear as expected with excellent dispersion.
Unlike my previous attempt, there is absolutely no hiss or 60 hz hum, when I turn down the volume. Dead quiet. A great start.
I've attached a few few pics to help visualize them.
Sorry about these being sideways. I guess the iPad keeps orientation data....funny looks fine on my Mac when viewing them.
Chris661
Thanks for the details. I'll have to dig out my notes to see what frequency I tuned the sub section for. I use WinISD, then switched to Mac which doesn't support it. From my (admittedly flakey) memory, it was in the neighbourhood of 100 - 120.
From playing around with the crossover, I've settled on 98 Hz. Above that the sub get very active.
A high pass is set for 30 hz currently LR48. Any lower and it gets very boomy.
Currently I'm balancing the drivers with volume adjust on the amps. Yes the noise floor is very low as a result.
When ready, I'll likely put these in a locked cabinet. Anyone else is allowed to play with the master volume and and other attempts to play with the toys will result in expulsion from the house. 🙂
(well, except for my wife, I kinda like her...)
Interestingly, I played with various crossover types and settled on 24 - it just sounded best.
TBD:
1 - Time alignment is something I've not played with. And have no idea how to determine if/when I have it right.
Any suggestions are very welcome.
2 - I'm just setting up RTA, have a mic, but need some time to hook it all up and learn.
Adding some objectivity to my ear is very welcome. And I'll end up learning a ton more.
(ok - I was a physics geek in high school)
3 - figure out digital in from the PC to the DCX.
4 - changing Bit rates - no idea.
5 - when the DCX turns on, its always on Mute. Makes sense, so that you don't blow the speakers with turn on thumps. Its also means a lot of fussing when turning on 3 amps, a PC, and the DCX. some centralized switching would be great.
Overall, this is going much better than any previous attempt and I'm optimistic that I can tune these better with some more knowledge. Moving toward pro-audio thinking has really helped me.
thanks
Olaf
One speaker is functional, the other still in the works.
Overall, without tuning, it already sounds pretty decent.
Full base, but not boomy. The sub are wire in parallel. The Crown K2 will be able to play 2 oms, its rated for that. Since the drivers will only take about 225 W and the amp can put out far more
Mids are very clear, maybe a bit too forward.
The highs are very clear as expected with excellent dispersion.
Unlike my previous attempt, there is absolutely no hiss or 60 hz hum, when I turn down the volume. Dead quiet. A great start.
I've attached a few few pics to help visualize them.
Sorry about these being sideways. I guess the iPad keeps orientation data....funny looks fine on my Mac when viewing them.
Chris661
Thanks for the details. I'll have to dig out my notes to see what frequency I tuned the sub section for. I use WinISD, then switched to Mac which doesn't support it. From my (admittedly flakey) memory, it was in the neighbourhood of 100 - 120.
From playing around with the crossover, I've settled on 98 Hz. Above that the sub get very active.
A high pass is set for 30 hz currently LR48. Any lower and it gets very boomy.
Currently I'm balancing the drivers with volume adjust on the amps. Yes the noise floor is very low as a result.
When ready, I'll likely put these in a locked cabinet. Anyone else is allowed to play with the master volume and and other attempts to play with the toys will result in expulsion from the house. 🙂
(well, except for my wife, I kinda like her...)
Interestingly, I played with various crossover types and settled on 24 - it just sounded best.
TBD:
1 - Time alignment is something I've not played with. And have no idea how to determine if/when I have it right.
Any suggestions are very welcome.
2 - I'm just setting up RTA, have a mic, but need some time to hook it all up and learn.
Adding some objectivity to my ear is very welcome. And I'll end up learning a ton more.
(ok - I was a physics geek in high school)
3 - figure out digital in from the PC to the DCX.
4 - changing Bit rates - no idea.
5 - when the DCX turns on, its always on Mute. Makes sense, so that you don't blow the speakers with turn on thumps. Its also means a lot of fussing when turning on 3 amps, a PC, and the DCX. some centralized switching would be great.
Overall, this is going much better than any previous attempt and I'm optimistic that I can tune these better with some more knowledge. Moving toward pro-audio thinking has really helped me.
thanks
Olaf
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