Hi there,
I have a couple of early 1970s 12" bass drivers - Philips AD 1256/W8 and I'm looking to do my first speaker build. I had orginally intended to build 2-way speakers using some other preloved tweeters (Electro Voice T35), but there would have been a large gap in the middle of the freq spectrum. The DIY audio forum was super helpful with this.
So, rather than spend more $$ and build a 3-way, I'm thinking of using the 12"drivers to build subs instead, and pair them with my current hifi speakers - Celestion Ditton 33 (also 1970s, 8W). According to WinISD, the Philips drivers will extend down to mid 30s Hz in an approx 100L sealed enclosure. Given that I'd be pairing the DIY subs with full range speakers - and to avoid really expensive crossover components - I'm thinking of a crossover freq of about 500Hz.
This post is just to sense-check my idea:
I see this exercise very much as a trial run/learning experience - but I would like to avoid any obvious errors and build something useful at the end of the day!
thanks in advance,
Steve
PS there are some more parameters/photos of the drivers in my post here: https://www.diyaudio.com/community/...sing-t-s-parameters-for-vintage-driver.396183
I have a couple of early 1970s 12" bass drivers - Philips AD 1256/W8 and I'm looking to do my first speaker build. I had orginally intended to build 2-way speakers using some other preloved tweeters (Electro Voice T35), but there would have been a large gap in the middle of the freq spectrum. The DIY audio forum was super helpful with this.
So, rather than spend more $$ and build a 3-way, I'm thinking of using the 12"drivers to build subs instead, and pair them with my current hifi speakers - Celestion Ditton 33 (also 1970s, 8W). According to WinISD, the Philips drivers will extend down to mid 30s Hz in an approx 100L sealed enclosure. Given that I'd be pairing the DIY subs with full range speakers - and to avoid really expensive crossover components - I'm thinking of a crossover freq of about 500Hz.
This post is just to sense-check my idea:
- does this approach make sense? Is done often?
- might there be any issues crossing over at 500Hz? (Note I'm planning to build and run 2 subs in stereo)
- any other issues/challenges?
I see this exercise very much as a trial run/learning experience - but I would like to avoid any obvious errors and build something useful at the end of the day!
thanks in advance,
Steve
PS there are some more parameters/photos of the drivers in my post here: https://www.diyaudio.com/community/...sing-t-s-parameters-for-vintage-driver.396183
I had a client with a pair of those (or simialr), we built a sub out of them for him. Pushed the Fs down a bit with lots of ModPodge, loaded them push-push, stuck them in a (very likely) too-small a box and made them aperiodic. Added a plate amp. They work quite wel.
dave
dave
500Hz seems to be a ridiculously high crossover point, rendering the 10" woofer in the Celestions semi-redundant. I'd cross between 80 and 100Hz, reducing the cone movement of the Celestion woofers and increasing mechanical power handling.
If you want a sub, you should set for 150Hz or Lower. Even 150Hz is high, , 120 to 100 is probably best. Thx standard, for AVR , set to below 80 with a second order xover (i believe).
What kid of amp, sub amp and xover system are you planning to use?
What kid of amp, sub amp and xover system are you planning to use?
I'd like to build the xover myself.
I originally planned to xover around 100Hz, but the component values (especially inductor) for the xover were difficult (using this online calculator: https://soundcertified.com/speaker-crossover-calculator/) - 100uF caps, 25mH inductors for 2nd order 2way Linkwitz-Riley
The amp is a vintage hifi - Kenwood KA-7100 (60 watt). No subwoofer output ;-)
I was hoping to drive subs and the Celestions with this amp. However, I'm open to taking a different approach, with a sub amp. If there's a good beginner thread on this, please link.
I'd appreciate any suggestions!
I originally planned to xover around 100Hz, but the component values (especially inductor) for the xover were difficult (using this online calculator: https://soundcertified.com/speaker-crossover-calculator/) - 100uF caps, 25mH inductors for 2nd order 2way Linkwitz-Riley
The amp is a vintage hifi - Kenwood KA-7100 (60 watt). No subwoofer output ;-)
I was hoping to drive subs and the Celestions with this amp. However, I'm open to taking a different approach, with a sub amp. If there's a good beginner thread on this, please link.
I'd appreciate any suggestions!
A passive XO at that frequency is a nightmare, will not work well, and the parts size can make just getting a plate amp cheaper.
dave
dave
Cool looking amp, those oldies can sound great specially with vinyl.
I agree with planet10, but I would also add that a plateamp will give you the freedom to find the best frequency for the xover, change the phase and all in a very simple and intuitive way. Just make sure that you choose one with speaker inputs.
I agree with planet10, but I would also add that a plateamp will give you the freedom to find the best frequency for the xover, change the phase and all in a very simple and intuitive way. Just make sure that you choose one with speaker inputs.
If your amp has a line out, you can also get a mini DSP or similar sistem, do the filtering in the digital domain and then send the signal to the final amp.
I use both plate subs and dsp and amplifier subs; the dsp gives you better control and easier multiple sub integration but nothing beats the simplicity of use of a plate amp.
I use both plate subs and dsp and amplifier subs; the dsp gives you better control and easier multiple sub integration but nothing beats the simplicity of use of a plate amp.
A plate amp is an ill-conceived proposal. He's using TWO subs. A plate amp requires the extra work of equalizing cabinet volumes. A pair of 2nd-order passive low pass filters are relatively cheap.
Low Pass
Other than that an active crossover and another amp is possibly the way forward. For amplifying the 20 - 120Hz range almost any amp will do (there's not a lot of quality down there).
Low Pass
Other than that an active crossover and another amp is possibly the way forward. For amplifying the 20 - 120Hz range almost any amp will do (there's not a lot of quality down there).
Sub/plate amps without phase continuous-fine-adjustment (knob) sounded less full to me due to interference and seriously constrained the XO point.
Hey, where are you in Australia. I am in Adelaide and have built more than a sensible number of speakers and subs.
eerk - exept now I look that flag looks subtly different. NZ? .... that notwithstanding, feel free to reach out😉
I agree with the above that a sub is a good idea for them, and that an active system (plate amp or other) is simple and quick.
My experience, which I am sure will have people with alternate expreiences, is that a sub is better as a sub. i.e. keep away from lower midrange and vocals and have an XO at 100Hz or preferably a touch lower.
You have options in DSP (miniDSP is fast and simple but not cheap, but very tuneable) or analogue which is cheaper but not tuneble. Truth is that once set up you will never (ever) touch them again, so while I am a DSP-O-phile I both see value in and use analogue. OK, I am a technophile instead😉
anyway, happy to help out, and if you are not 200km away, I can help with test and measurement and a bunch of spare kit if you need.
eerk - exept now I look that flag looks subtly different. NZ? .... that notwithstanding, feel free to reach out😉
I agree with the above that a sub is a good idea for them, and that an active system (plate amp or other) is simple and quick.
My experience, which I am sure will have people with alternate expreiences, is that a sub is better as a sub. i.e. keep away from lower midrange and vocals and have an XO at 100Hz or preferably a touch lower.
You have options in DSP (miniDSP is fast and simple but not cheap, but very tuneable) or analogue which is cheaper but not tuneble. Truth is that once set up you will never (ever) touch them again, so while I am a DSP-O-phile I both see value in and use analogue. OK, I am a technophile instead😉
anyway, happy to help out, and if you are not 200km away, I can help with test and measurement and a bunch of spare kit if you need.
Thanks again everyone -
@googlyone - yep it's a NZ flag!! Thanks for the offer anyway!
I'm sold on the plate amp idea. Will probably go for one of these as it'll run on NZ power (240V), adjustable XO, and has high-pass filter for the main speakers: https://www.daytonaudio.com/product/1092/spa250-250w-subwoofer-plate-amplifier
Will it be possible/advisable to drive 2 sub enclosures with one amp? In parallel?
Alternately I could build a 2x12 sub but the modelling in WinISD (Sealed enclosure, approx 100L) makes it look like I'll get better extension from a 1x12. If i make a matching pair i can sit the Celestions on top.
@googlyone - yep it's a NZ flag!! Thanks for the offer anyway!
I'm sold on the plate amp idea. Will probably go for one of these as it'll run on NZ power (240V), adjustable XO, and has high-pass filter for the main speakers: https://www.daytonaudio.com/product/1092/spa250-250w-subwoofer-plate-amplifier
Will it be possible/advisable to drive 2 sub enclosures with one amp? In parallel?
Alternately I could build a 2x12 sub but the modelling in WinISD (Sealed enclosure, approx 100L) makes it look like I'll get better extension from a 1x12. If i make a matching pair i can sit the Celestions on top.
Are you sure that plate amplifier has a high pass filter for your main speakers? I had a read and came away with the understanding that it does a pass through, not HPF for your mains.
To me, having that high pass filter or your mains is essential to really getting the full benefit of having a sub in a system. So I would not compromise on that, even thouh it will probably make things more complicated and reduce your options.
I think you will find that one 12" sub does a good job. Of course two is ALWAYS better than one, even if unnecessary and excessive. If you have family members to keep on board with this, that may add a challenge.
To me, having that high pass filter or your mains is essential to really getting the full benefit of having a sub in a system. So I would not compromise on that, even thouh it will probably make things more complicated and reduce your options.
I think you will find that one 12" sub does a good job. Of course two is ALWAYS better than one, even if unnecessary and excessive. If you have family members to keep on board with this, that may add a challenge.
Yeah agreed re: HPF. Thanks for point it out. I had assumed the ‘freq’ Knob was a sort of variable 2-way XO…!
According the user manual, the high level ‘through’ has a HPF at 125Hz, -6dB/octave.
So that would mean I’d be crossing over pretty high for a sub, but all the more reason to build 2 for a stereo image, right? I have a supportive family!
According the user manual, the high level ‘through’ has a HPF at 125Hz, -6dB/octave.
So that would mean I’d be crossing over pretty high for a sub, but all the more reason to build 2 for a stereo image, right? I have a supportive family!
Attachments
Your speakers seem to be 16 Ohms, that is a little bit high for most plate amps. By going patallel with one amp, your impedance will be halved. I am assuming that you want to use both as an extension to the mains close to them
That 125Hz at 6dB rolloff for your majns is i guess better than nothing. You will need external amplification for your mains. Given you are not crosding to tiny speakers i think you will be ok.
I have some of those old philips 12 inch drivers in my shed. If i am right they were used in an old ETI kit. They should work a treat for you.
I would definitely go one per side. 😉
I have some of those old philips 12 inch drivers in my shed. If i am right they were used in an old ETI kit. They should work a treat for you.
I would definitely go one per side. 😉
@Frabor - Yes the subs will be an extension to the mains and close to them. The Philips 12" drivers are 8 ohm.
If I run the 12" drivers in parallel it'll be a 4ohms load for the plate amp, right? Series would be 16 ohm. Do you think parallel would work best?
The Celestion Ditton 33s are 8ohm but powered by a different source
@googlyone - cool, I'll go with this plan - thanks again.
The main speakers will be driven by a Kenwood KA-7100 (60 watt) vintage integrated amp that drives the celestions well at present. The new set up will mostly be put to use for house parties. I presume the celestions will be happier at higher volumes for longer periods with the plate amp and subs doing all the work below 125Hz - that's the idea anyway.
Some day I might build some 2-ways to replace the celestions. I'm keen to use the Electro Voice T35 horn tweeters and make my own passive XO.
Philips 12" drivers were from an old pair of monitors from a television studio. Sealed in quite a small enclosure (approx 40-40L) with a strange array of tweeters and mids. Sounded okay but i want to DIY something nicer sounding and looking
If I run the 12" drivers in parallel it'll be a 4ohms load for the plate amp, right? Series would be 16 ohm. Do you think parallel would work best?
The Celestion Ditton 33s are 8ohm but powered by a different source
@googlyone - cool, I'll go with this plan - thanks again.
The main speakers will be driven by a Kenwood KA-7100 (60 watt) vintage integrated amp that drives the celestions well at present. The new set up will mostly be put to use for house parties. I presume the celestions will be happier at higher volumes for longer periods with the plate amp and subs doing all the work below 125Hz - that's the idea anyway.
Some day I might build some 2-ways to replace the celestions. I'm keen to use the Electro Voice T35 horn tweeters and make my own passive XO.
Philips 12" drivers were from an old pair of monitors from a television studio. Sealed in quite a small enclosure (approx 40-40L) with a strange array of tweeters and mids. Sounded okay but i want to DIY something nicer sounding and looking