Hi,
I'm looking at extending the bottom range of my system a bit with a sub. This is in a small room (12 square meters ~4m x 3m).
I have 2way speakers I built with Accuton C173 drivers and Mundorf AMT tweeters. 17l vented enclosure. They sound wonderful but sometimes, I little more "oomph" at the low end would be nice.
Amp is tube based 35W. Loud enough for this room.
I figure an active sub is called for that would feed off the speaker connection from the amp (hi-level connection). That needs to happen in a way that doesn't do wired things to the impedance that the amp sees. The speakers have a very well designed impedance lineraziation which works well with the tube amp and I don't want to mess that up. I don't know much about active sub-woofer designs but in theory, it shouldn't be a problem I think as that input would have super high impedance that is totally getting dominated by the impedance of the speakers. But then again, I have not done this before so I'd rather use a prooven design if possible.
Obviously, bringing a solid-state active subwoofer into a tube setup might feel like a bit (or a lot) of blasphemy to some but I think it's a good option in my case. I don't have space in this room for huge full-range speakers so I'm good with mixing whatever gets the job done as long as the quality is right.
Given that the system is of quite high quality, I want the sub to match that and use high a high quality driver and electronics. Using ready-made modules would be OK but I'd rather build the electronics myself so I have some say in parts selection.
With the limited expirience I have, just looking around, I think I'd build a closed box (60l) for a 15" Timphany STW. I think a vented design would be too huge given that this is a small room. I don't need a lot of volume. I'ts just about extending the range of the system into the lower regions while maintaing tightness and definition of the sound.
Rather then figuring this all out on my own (which is fun but also error-prone), if someone knows about an exiting project which has proven itself in practice, I'd rather start with that than building from scratch.
General question about high-level inputs/outputs and crossovers in active subs. Would this be design in such a way that it represents a high-pass to the signal that is going to the main speakers or would it just represent a voltag divider and sit in parallel with the main speakers and then use a low-pass internally when feeding its own output stage that's hooked up to the driver?
Thanks,
Lars
I'm looking at extending the bottom range of my system a bit with a sub. This is in a small room (12 square meters ~4m x 3m).
I have 2way speakers I built with Accuton C173 drivers and Mundorf AMT tweeters. 17l vented enclosure. They sound wonderful but sometimes, I little more "oomph" at the low end would be nice.
Amp is tube based 35W. Loud enough for this room.
I figure an active sub is called for that would feed off the speaker connection from the amp (hi-level connection). That needs to happen in a way that doesn't do wired things to the impedance that the amp sees. The speakers have a very well designed impedance lineraziation which works well with the tube amp and I don't want to mess that up. I don't know much about active sub-woofer designs but in theory, it shouldn't be a problem I think as that input would have super high impedance that is totally getting dominated by the impedance of the speakers. But then again, I have not done this before so I'd rather use a prooven design if possible.
Obviously, bringing a solid-state active subwoofer into a tube setup might feel like a bit (or a lot) of blasphemy to some but I think it's a good option in my case. I don't have space in this room for huge full-range speakers so I'm good with mixing whatever gets the job done as long as the quality is right.
Given that the system is of quite high quality, I want the sub to match that and use high a high quality driver and electronics. Using ready-made modules would be OK but I'd rather build the electronics myself so I have some say in parts selection.
With the limited expirience I have, just looking around, I think I'd build a closed box (60l) for a 15" Timphany STW. I think a vented design would be too huge given that this is a small room. I don't need a lot of volume. I'ts just about extending the range of the system into the lower regions while maintaing tightness and definition of the sound.
Rather then figuring this all out on my own (which is fun but also error-prone), if someone knows about an exiting project which has proven itself in practice, I'd rather start with that than building from scratch.
General question about high-level inputs/outputs and crossovers in active subs. Would this be design in such a way that it represents a high-pass to the signal that is going to the main speakers or would it just represent a voltag divider and sit in parallel with the main speakers and then use a low-pass internally when feeding its own output stage that's hooked up to the driver?
Thanks,
Lars
Take also a look at the SB34NRX75-6, that is one of the better subwoofer drivers arround i think for high quality music. It goes low but don't becom:e a jackhammer like so many subs that go low are. This driver can work in a 75L sealed (or bigger to about 150L) for an F6 of 30Hz and an F10 of 23Hz without any eq. And it can do that 30Hz at +102dB also.
I really like the Dayton Audio DCS 205 in a small closed 14 liter sub with a 580 uF high pass capacitor. Very clean and plays loud. I used a cheap Mivoc plate amp (Europe), this may come close enough: https://www.parts-express.com/Dayton-Audio-SA100-100W-Subwoofer-Amplifier-300-802 depending on your x-over point, a plate amp with boost is necessary.
I used it with a variety of speaker tube-amp combinations with the high level inputs on the Mivoc. Especially with classical music, it enhances spatiallity. Boost and sensitivity of the plate amp needs attention, you do not want to have the sub switching on and off all the time, because the "high level" input is to small to keep it awake.
I know the Dayton DCS is not seen as high quality, the group delay however is HQ.
I used it with a variety of speaker tube-amp combinations with the high level inputs on the Mivoc. Especially with classical music, it enhances spatiallity. Boost and sensitivity of the plate amp needs attention, you do not want to have the sub switching on and off all the time, because the "high level" input is to small to keep it awake.
I know the Dayton DCS is not seen as high quality, the group delay however is HQ.
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With regard to plate amps, th Monacor Sam-2 looks promising for my purposes.
The Dayton-Audio PlateAmp is interesting b/c it also has outputs for the high-level inputs. Do you know if those are filtered, or are they just a pass-through?
I think an 8" driver is a bit on the small side but using closed box and some capacitance to create a HPF for a resonance bump and also save on box-size that way seems like a nice approach.
The Dayton-Audio PlateAmp is interesting b/c it also has outputs for the high-level inputs. Do you know if those are filtered, or are they just a pass-through?
I think an 8" driver is a bit on the small side but using closed box and some capacitance to create a HPF for a resonance bump and also save on box-size that way seems like a nice approach.
I would not call 2+ cubes "small" in any regard. In your 13' x 9' (approx) room, you really don't need anything that big either.
Wouldn't a box closer to 1ft^3 trip your trigger easier? Especially if it's extremely capable?
You should check out my Overdrive10 design, as it has attributes that can favor smaller rooms like;
Warning, may need heavy cab to prevent design shaking violently. Spiked feet or rubber grippy feet encouraged.
Later,
Wolf
Wouldn't a box closer to 1ft^3 trip your trigger easier? Especially if it's extremely capable?
You should check out my Overdrive10 design, as it has attributes that can favor smaller rooms like;
- the steeper lowpass due to alignment. This means it gets outta the way and lets the stereo pair do what they do without it running through their range.
- physical size is 26 ltrs.
- unboosted has response to 30Hz, so room can contribute to the very low end. Boosted option for more oomph if required for movies.
- high-level inputs on the amplifier used.
- clean, low HD, bandpass system without port noise due to passive radiator exit.
- reduced excitation of higher room mode frequencies due to rolloff.
Warning, may need heavy cab to prevent design shaking violently. Spiked feet or rubber grippy feet encouraged.
Later,
Wolf
Thanks. I have not read up much on bandpass designs. This looks really interesting. I‘ll read into that some more. Could be a great solution for my scenario…
A push-push design would be great say 2 x 10 inch in closed box with or without high pass capacitor. Maybe alu cone wavecor or peerless xxl's in 8 ohm. That would eliminate most of the "box" sound.
push-push closed box with highpass is what I have also been reading up quite a bit on so far.
2x NE265W-08 with a 40l box and ~1400µF looks quite nice when I run it...
I'll also check out the wavecor you mentioned but I also want to read up on the bandpass stuff as that sounds quite interesting as well
Monacor SAM-2 looks like a nice plate amp for my purposes: https://www.monacor.com/products/components/energy-measuring-and-diy/diy--/sam-2/
2x NE265W-08 with a 40l box and ~1400µF looks quite nice when I run it...
I'll also check out the wavecor you mentioned but I also want to read up on the bandpass stuff as that sounds quite interesting as well
Monacor SAM-2 looks like a nice plate amp for my purposes: https://www.monacor.com/products/components/energy-measuring-and-diy/diy--/sam-2/
There is no like button on DIY-audio. So here we go: NICE! Both the Peersless and Wavecor have a tad higher Qts compared to the NE265W-08 with same Fs.
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The Wavecor SW259WA02 might be something. I can get a nice looking simulation with a 2 drivers in a 30l closed box and 2000µF (black line is w/o cap)
I like that the wavecor drivers have an aluminium cone. I find that nice to go with the ceramic accutons on the main speakers (accutons for the sub would not be worth it price/performance wise, I think). The stiffer alu cones should make for good transient response which is what I love about the accutons.
Transient response is also something which might be something that is hard to get right on a bandpass design and margis for error are slim there. I find the idea of a bandpass design really intruiging but given my level of expirience it might not be the right thing for me to do at this stage... I feel like a closed push-push is more in line with my skill level...
I like that the wavecor drivers have an aluminium cone. I find that nice to go with the ceramic accutons on the main speakers (accutons for the sub would not be worth it price/performance wise, I think). The stiffer alu cones should make for good transient response which is what I love about the accutons.
Transient response is also something which might be something that is hard to get right on a bandpass design and margis for error are slim there. I find the idea of a bandpass design really intruiging but given my level of expirience it might not be the right thing for me to do at this stage... I feel like a closed push-push is more in line with my skill level...
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Closed box, would be the most "exact" subwoofer too, especially in push-push. Best of luck! Be sure it does not dip too low in impedance with the capacitor added.
Some other tweaks: strictly symetric cabinet for the opposing woofers. Seperate volumes for the woofers, seperate volume for the plate amp. And watch the voltage rating of those bipolar caps.
No experience and high ambitions sparkled with overconfidence is a sure way into audio DIYS disaster.
You want to design a sub woofer, build a cabinet, modify electronics and make it all work in your room? May be a bit too much for a start?
First, for your room you will need a DSP.
Second, high filter your tube amp, as it and your speakers will play on another level that way. So get a 2 in 4 out DSP.
Third, basics: The smaller the woofer, the higher the power needed, even for moderate levels.
Don't even consider a sub amp below a clean 150W into 4 Ohm ever.
Two subs work better than one. One amp per speaker is better than one serving two. If on a budget, get a PA amp. No sound quality downsides, just no fancy high end Mundorf look...
The more complicated the cabinets design gets, the worse the impulse response.
Closed = fine
Closed HP = just as good
Vented = may be OK
Band Pass = no high end HIFI, for Car-Fi OK
Horn = too large.
(This is very basic, but closed sure will get you the best result, while leaving very little room for mistakes)
If you believe blondes are naive and red headed girls are always horny, keep talking about metal, ceramic and paper cones, Kevlar and Carbon.
The truth is, there are good subwoofer chassis, even made from plastic. Try to see it this way: Making a good speaker from a material not really good for speakers is more expensive than using a simple, well suited material. If you want to spent a lot of money, go exotic. In most cases paper is best and good sound does not come from ceramic just because it is expensive to make.
The size of the cone:
I would never consider as sub woofer smaller than 10" /25cm. Leave that to JBL and Logitech. You want fast response. The larger the cone, the less movement for the same sound pressure, the faster the sub. Even if scientifically speaking, this fast bass talk is nonsense.
Small cone, high x-max subs get expensive, a good 10" will often cost less than a high excursion 8". The smaller a cabinets gets, the worse the net volume to outer volume becomes. If you can integrate a 25cm cube in your room, one with 35cm sides will not be a real problem, but volume jumps from 16 to 43 liters. Should even fit a few 12".
You should be able to realize a great sub installation made from raw MDF for 600€ . Do not spent money on too small mediocre parts you have to replace later. If unsure, look for used eBay prices. People sell stuff they don't like cheap and keep the good parts.
Even as this is a huge sales argument with commercial sub's, an amp build into a bass cabinet is not the best place for electronics. To be precise, it is the worst you can find in your room. Think about it and spell "Plate Amp".
If you build your cabinet first, you can use sellers like Thomann with a money back offer to try out components. Be warned, after tuning in your system with a DSP (a cheap measuring system helps a lot) there is no way back. 100%.
A box is not just a box. For a subwoofer the cabinet is just as important as the speaker , amp and DSP. Some forums in Germany do not see it this way and the lazy fools tell you to ignore reinforcements and bracing. Do not ruin your project by falling for these traps.
You want to design a sub woofer, build a cabinet, modify electronics and make it all work in your room? May be a bit too much for a start?
First, for your room you will need a DSP.
Second, high filter your tube amp, as it and your speakers will play on another level that way. So get a 2 in 4 out DSP.
Third, basics: The smaller the woofer, the higher the power needed, even for moderate levels.
Don't even consider a sub amp below a clean 150W into 4 Ohm ever.
Two subs work better than one. One amp per speaker is better than one serving two. If on a budget, get a PA amp. No sound quality downsides, just no fancy high end Mundorf look...
The more complicated the cabinets design gets, the worse the impulse response.
Closed = fine
Closed HP = just as good
Vented = may be OK
Band Pass = no high end HIFI, for Car-Fi OK
Horn = too large.
(This is very basic, but closed sure will get you the best result, while leaving very little room for mistakes)
If you believe blondes are naive and red headed girls are always horny, keep talking about metal, ceramic and paper cones, Kevlar and Carbon.
The truth is, there are good subwoofer chassis, even made from plastic. Try to see it this way: Making a good speaker from a material not really good for speakers is more expensive than using a simple, well suited material. If you want to spent a lot of money, go exotic. In most cases paper is best and good sound does not come from ceramic just because it is expensive to make.
The size of the cone:
I would never consider as sub woofer smaller than 10" /25cm. Leave that to JBL and Logitech. You want fast response. The larger the cone, the less movement for the same sound pressure, the faster the sub. Even if scientifically speaking, this fast bass talk is nonsense.
Small cone, high x-max subs get expensive, a good 10" will often cost less than a high excursion 8". The smaller a cabinets gets, the worse the net volume to outer volume becomes. If you can integrate a 25cm cube in your room, one with 35cm sides will not be a real problem, but volume jumps from 16 to 43 liters. Should even fit a few 12".
You should be able to realize a great sub installation made from raw MDF for 600€ . Do not spent money on too small mediocre parts you have to replace later. If unsure, look for used eBay prices. People sell stuff they don't like cheap and keep the good parts.
Even as this is a huge sales argument with commercial sub's, an amp build into a bass cabinet is not the best place for electronics. To be precise, it is the worst you can find in your room. Think about it and spell "Plate Amp".
If you build your cabinet first, you can use sellers like Thomann with a money back offer to try out components. Be warned, after tuning in your system with a DSP (a cheap measuring system helps a lot) there is no way back. 100%.
A box is not just a box. For a subwoofer the cabinet is just as important as the speaker , amp and DSP. Some forums in Germany do not see it this way and the lazy fools tell you to ignore reinforcements and bracing. Do not ruin your project by falling for these traps.
PS
just found this. You can build it a bit smaller, as closed box does not react that critical to +-10% volume. Two of these, back to back, should have anything you need, but even one should rock the house.
https://www.oaudio.de/lautsprecherb...usaetze/subwoofer-sw10-8-pc.html#&gid=1&pid=2
Very nice modern chassis.
just found this. You can build it a bit smaller, as closed box does not react that critical to +-10% volume. Two of these, back to back, should have anything you need, but even one should rock the house.
https://www.oaudio.de/lautsprecherb...usaetze/subwoofer-sw10-8-pc.html#&gid=1&pid=2
Very nice modern chassis.
Bandpasses are not only for car audio, nor are they unclean to not work in hifi situations. You have to design them right. Using a PR is the first benefit. They are really clean systems in terms of HD.
The idea by Zackplonk was to use the high level in from a plate amp. The signal for the subwoofer plate amp, is coming from a 2 x 30 Watt tube amplifier. In this case there will be a correlation between the size of the subwoofer plate amp and the effiency of the mainspeakers. A calculation of max SPL of the main speakers would be a good starting point to figure out this relation. No need for two 1.000 Watt subwoofer amps waiting on a "GO" signal never to come.
You might find this approach not usefull, since no multiple subs, DSP etc, etc. It's is still a valid approach. I don't think he is getting rid of that tubeamplifier soon. I asume there is no low level output on this tubeamp.
About the "never below 150 Watt subamp" So also for cornerhorns with 107dB? No relation to the mainspeakers? This is a tube driven system in a small room.... Do the math.
Also Tone, you seem to make some strawman assumptions about Zackplonk and his "love" for expensive cone materials. He seemed ok with aluminium cone's for the sub, instead of ceramic's and quite understanding of the difficulty of bandpass, br and closed box.
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I do run subs in a waw (woofer assisted wideband) 2 way config with a passive crossover and a 35w tube amp and got all the bass i want from it. The driver is 89dB sensitive and box is tuned to 32Hz so that you need +150w for a hifi sub is ********. That 35w is even way to powerfull for my space (4x6x2.5m) and when half open my neighbours alredy start to complain...
Is it just fundamental opposition or a lack of experience with HIFI that drives some to write such nonsense?
A usual 2x 30W tube amp can be driven much harder than a transistor amp of the same rating.
Then have a look at the energy distribution of music if you cut of your mains at 100 Hz. 60W from a tube for the mains will easily keep up with 150W for the sub. That is what I wrote is the minimum. 150W is not 1000W.
Stronger amps have other advantages than being able to drive cones to extreme excursions. I know that owners of little plate amps do not like this truth and often take this fact very personal. Look : "Dinky Toy subwoofer amps".
Maybe some have never experienced a strong amp in exchange for small one on the same sub chassis. If so, enlarge your horizon or you will miss a lot of really impressing audio. Much of the so called slow and smeared bass is an amp to weak to control the resonance of the woofer. Yes, different amps can sound different!
He has presented his ideas for a system, that does not mean he wants it exactly this way. He wanted ideas.
Not high passing the mains signal will take away more than 50% of the advantage a good subwoofer solution can give. Extracting power from the tube amp and heating up the voice coil of the mains mid bass is no piece of art. There is absolutely no advantage in doing this.
Using the output of a power amp to drive another power amp is a usual no-no with HIFI. Again, I smell cheap car HIFI.
A DSP today is the best way to integrate an audio system into a room. Less complicated than a passive or active x-over, better and cheaper. Maybe too much win for some who have invested heavily in solutions of the past and don't want to admit we can do better today for a fraction of the cost.
On the day the thread starter will activate his new subwoofer for the first time, he will hear what "modes" do inside of his room. He will not be happy having them present. The same physics that made his small speakers sound more acceptable will turn against him.
People at forums will happily tell him about things he "might try", like building bass traps, getting an expensive "Anti Mode" or other high cost and room consuming solutions.
With a DSP he will have a perfect cure on his fingertips at no extra costs. All he needs to do is to set a few simple filter. Often even a simple calculator will tell him what to do, a good 100$ USB microphone will show him a clear picture of cause and cure.
I do not start a discussion about band pass woofer. I have build a few and still use one for a sound system. There are a few out there that might even work well for HIFI. Anyway, the chance to predict the (neutral) sound of a closed subwoofer is near to 100%, maybe 5% for a band pass. Over the years I never experienced a principle that was disliked by so many people, for the "one note bass out of a box" sound.
If I give advise to people I don't know, I do not talk about things that "might work in some cases", but about the solution that will have the least chance to fail while full filling his expectations. Often better than he could imagine.
Ignoring the 40-200 € expense for a cabinet, a 100€ DSP, a 220 € amp, 30€ wires and a 120€ speaker with the option to double up, he will get something to make him very happy. Throw in a 110€ calibrated USB microphone and he will even know why he likes it so much plus enable a fine tune at the edges.
Measuring is disliked by many, I know that much to well. It is the end of guessing and talking nonsense.
A usual 2x 30W tube amp can be driven much harder than a transistor amp of the same rating.
Then have a look at the energy distribution of music if you cut of your mains at 100 Hz. 60W from a tube for the mains will easily keep up with 150W for the sub. That is what I wrote is the minimum. 150W is not 1000W.
Stronger amps have other advantages than being able to drive cones to extreme excursions. I know that owners of little plate amps do not like this truth and often take this fact very personal. Look : "Dinky Toy subwoofer amps".
Maybe some have never experienced a strong amp in exchange for small one on the same sub chassis. If so, enlarge your horizon or you will miss a lot of really impressing audio. Much of the so called slow and smeared bass is an amp to weak to control the resonance of the woofer. Yes, different amps can sound different!
He has presented his ideas for a system, that does not mean he wants it exactly this way. He wanted ideas.
Not high passing the mains signal will take away more than 50% of the advantage a good subwoofer solution can give. Extracting power from the tube amp and heating up the voice coil of the mains mid bass is no piece of art. There is absolutely no advantage in doing this.
Using the output of a power amp to drive another power amp is a usual no-no with HIFI. Again, I smell cheap car HIFI.
A DSP today is the best way to integrate an audio system into a room. Less complicated than a passive or active x-over, better and cheaper. Maybe too much win for some who have invested heavily in solutions of the past and don't want to admit we can do better today for a fraction of the cost.
On the day the thread starter will activate his new subwoofer for the first time, he will hear what "modes" do inside of his room. He will not be happy having them present. The same physics that made his small speakers sound more acceptable will turn against him.
People at forums will happily tell him about things he "might try", like building bass traps, getting an expensive "Anti Mode" or other high cost and room consuming solutions.
With a DSP he will have a perfect cure on his fingertips at no extra costs. All he needs to do is to set a few simple filter. Often even a simple calculator will tell him what to do, a good 100$ USB microphone will show him a clear picture of cause and cure.
I do not start a discussion about band pass woofer. I have build a few and still use one for a sound system. There are a few out there that might even work well for HIFI. Anyway, the chance to predict the (neutral) sound of a closed subwoofer is near to 100%, maybe 5% for a band pass. Over the years I never experienced a principle that was disliked by so many people, for the "one note bass out of a box" sound.
If I give advise to people I don't know, I do not talk about things that "might work in some cases", but about the solution that will have the least chance to fail while full filling his expectations. Often better than he could imagine.
Ignoring the 40-200 € expense for a cabinet, a 100€ DSP, a 220 € amp, 30€ wires and a 120€ speaker with the option to double up, he will get something to make him very happy. Throw in a 110€ calibrated USB microphone and he will even know why he likes it so much plus enable a fine tune at the edges.
Measuring is disliked by many, I know that much to well. It is the end of guessing and talking nonsense.
On topic, where is the nonsense in the Wavecor Push-Push 2 x 10 inch closed box with high pass capacitor subwoofer? Nobody is talking about "toy" amplifiers, that's another strawman. The last suggestion from the topic starter was this 200 Watt amp: https://www.monacor.com/products/components/energy-measuring-and-diy/diy--/sam-2/
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