Hi, I'm going to build an active subwoofer hidden in a small table next to the sofa, the problem is that I have no experience in speaker design.
I have already built several loudspeakers, Full Statements, Natalie P, Kairos, Rogers Ls3 / 5a so I have at least a good build experience.
Currently I tried to use the SpeakerBoxLite software using the Dayton Audio ULTIMAX UM12-22 as a driver, I was able to combine something but I want to understand if my result makes sense or not. Can anyone take a look at the attached pictures and give me an opinion? Thank you.
I have already built several loudspeakers, Full Statements, Natalie P, Kairos, Rogers Ls3 / 5a so I have at least a good build experience.
Currently I tried to use the SpeakerBoxLite software using the Dayton Audio ULTIMAX UM12-22 as a driver, I was able to combine something but I want to understand if my result makes sense or not. Can anyone take a look at the attached pictures and give me an opinion? Thank you.
Hi, the woofer is at risk when people accidentally kick in it. I'd rather mount it down firing on the bottom, and elevate the table on feet. Also the vent tube seems too long, resulting in the "organ pipe" effect (one note booming). Recalculate with larger diameter that would result in reduced length. Or perhaps you can use two shorter tubes. You can terminate the outer end of the tube(s) with some rounded flange for reducing wind noise, something like this:
https://www.amazon.co.uk/Winwill-Speaker-Subwoofer-Reflex-53x100mm/dp/B0719L4XZR
Important is strong cross bracing of the top, bottom and sides, otherwise they will vibrate. 21 mm is not very thick. What material will you use: MDF, plywood?
https://www.amazon.co.uk/Winwill-Speaker-Subwoofer-Reflex-53x100mm/dp/B0719L4XZR
Important is strong cross bracing of the top, bottom and sides, otherwise they will vibrate. 21 mm is not very thick. What material will you use: MDF, plywood?
Larger diameter means LONGER.
One note booming is the result of too high a Q. Not that the port is long. Typical too small a box, tuned too high
Subs do need to be quite stiffly built. I find bitch ply to be the better material for subs. 21 mm minimum if correctly braced. . I have not tried the ultra high density fiber board.
You can radiate backwards as easily as to the front. Subs do not matter much.
I do not build ported subs. A low Q sealed sub ( .6 to critical .5) blends with room gain much better. The less eq needed the better.
Give me a chance and I will toss the driver into WinISD and see what I get for tuning options.
What are you planning for the amplifier?
One note booming is the result of too high a Q. Not that the port is long. Typical too small a box, tuned too high
Subs do need to be quite stiffly built. I find bitch ply to be the better material for subs. 21 mm minimum if correctly braced. . I have not tried the ultra high density fiber board.
You can radiate backwards as easily as to the front. Subs do not matter much.
I do not build ported subs. A low Q sealed sub ( .6 to critical .5) blends with room gain much better. The less eq needed the better.
Give me a chance and I will toss the driver into WinISD and see what I get for tuning options.
What are you planning for the amplifier?
That driver seems to be designed for a sealed box. Very low EBP. BIG box. 130L and stuff to lower the Q.
400W would give 108 dB without exceeding X-max. LOUD!
400W would give 108 dB without exceeding X-max. LOUD!
Thanks for the answers. I am reading a lot of discussions on the web about subwoofer construction and I am beginning to realize that a reflex cabinet is really difficult to make and involves a degree of knowledge that I obviously do not possess.
Too much missing information and too many doubts ...
For a novice like me, perhaps it is better to focus on a closed case project.
In this regard, I would like to have some clarifications:
Can the shape of the case be changed at will as long as the recommended volume is respected?
Does the crate need to be filled with material such as dacron?
Do I need a dedicated amplifier with dsp or is the calibration done with the Denon x3100 audissey enough?
Thanks so much for the help.
Too much missing information and too many doubts ...
For a novice like me, perhaps it is better to focus on a closed case project.
In this regard, I would like to have some clarifications:
Can the shape of the case be changed at will as long as the recommended volume is respected?
Does the crate need to be filled with material such as dacron?
Do I need a dedicated amplifier with dsp or is the calibration done with the Denon x3100 audissey enough?
Thanks so much for the help.
You are exactly right, sealed is more forgiving. A sub is an excellent first project as they are very not critical. Sealed less than ported. Ported subs can give yo fits with port dimensions big enough not to "chuff" I found even a 5 inch on a 10 to be audible! Passive radiators are the fix, but cost doubles.
We prefer to not have dimensions in even multiples to reduce resonances, but for a sub, it really does not matter. The volume matters. Actually, a sealed box is a special case of a ported box with the port closed. Same math. Mother nature likes things tidy.
Many viewpoints on stuffing material. In the old days we used fiberglass in sealed boxes. Plain pillow stuffing is slippery so not the best. You can get better generic stuffing from Parts Express. Poly or shredded blue jeans. Back when I started all the hype was for "long hair wool" Hype.
If you build a cabinet to the modeled size, then lightly stuffing will bring it into the target Q. Lower the Q, the better INMO. I target .5 for subs, but that is often a big box. .7 is the electrical "perfect" for a 2nd order roll-off. Most of mine wind up more like .6. If the box is too small, you get a little hump and a higher roll off.
Audessy will take care of it. Any old plate amp will do fine. They are not that critical. I run old O-audio plates that were lower distortion than most, but nothing really wrong with a Dayton plate. We use DSP plates for main stereos where we do not have host EQ.
If you get the bug, I suggest building a 2-way kit, and use it to do the full design process following what the kit designer did to see what tradeoffs they used and think about why. Lower risk than jumping in and not knowing the outcome. You can work out your measurement and CAD procedures. It takes some learning as it is real engineering. At least we have programs that do the math now. When I started, no such luck.
One of the hardest things is understanding a rational target. Beginners often think " I want it flat to 20 Hz". Well, no. You want it to be smooth in a room and rooms are part of the equation. Room gain, placement etc. Turns out, a sub that is rolling off not much below the crossover is actually what works. Some also have insane ideas on level. 130 dB or something. ( 4 15's will do it) But in reality, you need no where near that much. I see a lot of sub "speed, impact, punch" all of which actually have nothing to do with the sub.
A lot to learn. If you are in the Piedmont, PM me.
We prefer to not have dimensions in even multiples to reduce resonances, but for a sub, it really does not matter. The volume matters. Actually, a sealed box is a special case of a ported box with the port closed. Same math. Mother nature likes things tidy.
Many viewpoints on stuffing material. In the old days we used fiberglass in sealed boxes. Plain pillow stuffing is slippery so not the best. You can get better generic stuffing from Parts Express. Poly or shredded blue jeans. Back when I started all the hype was for "long hair wool" Hype.
If you build a cabinet to the modeled size, then lightly stuffing will bring it into the target Q. Lower the Q, the better INMO. I target .5 for subs, but that is often a big box. .7 is the electrical "perfect" for a 2nd order roll-off. Most of mine wind up more like .6. If the box is too small, you get a little hump and a higher roll off.
Audessy will take care of it. Any old plate amp will do fine. They are not that critical. I run old O-audio plates that were lower distortion than most, but nothing really wrong with a Dayton plate. We use DSP plates for main stereos where we do not have host EQ.
If you get the bug, I suggest building a 2-way kit, and use it to do the full design process following what the kit designer did to see what tradeoffs they used and think about why. Lower risk than jumping in and not knowing the outcome. You can work out your measurement and CAD procedures. It takes some learning as it is real engineering. At least we have programs that do the math now. When I started, no such luck.
One of the hardest things is understanding a rational target. Beginners often think " I want it flat to 20 Hz". Well, no. You want it to be smooth in a room and rooms are part of the equation. Room gain, placement etc. Turns out, a sub that is rolling off not much below the crossover is actually what works. Some also have insane ideas on level. 130 dB or something. ( 4 15's will do it) But in reality, you need no where near that much. I see a lot of sub "speed, impact, punch" all of which actually have nothing to do with the sub.
A lot to learn. If you are in the Piedmont, PM me.
As a table you should consider doing push-push woofers so as to greatly minimize box resonances by actively removing the driving force. So i would choose a couple 10” intead of a single 12”
While a BR will model as a lower cutoff do not forget room gain. I much prefer sealed for really low.
And the kick the driver, if one can make that difficult (a single woofer would be used down firing), here is a sketch i did of an isobarik push-push box with woofers hidden away.
It could be done with just a pair of woofers as well.
dave
While a BR will model as a lower cutoff do not forget room gain. I much prefer sealed for really low.
And the kick the driver, if one can make that difficult (a single woofer would be used down firing), here is a sketch i did of an isobarik push-push box with woofers hidden away.
It could be done with just a pair of woofers as well.
dave
You don't need even HDF if you brace it correctly, and I've seen very few that are.
Face it down, or up with a spaced top, towards the seating or recess it and use a perforated metal grille. Just giving practical implementations, not aesthetic ones especially for the last one.
I have been looking at HDF as it machines so well. More for baffles. But much stiffer and still somewhat "dead"
Then "real" MDF, and another step down to the junk sold in big box stores as MDF.
My current sub is 1/2 play with ceramic plates laminated inside, then 1/8 oak on the outside. Only 2 cubic feet but I can't lift one.
Then "real" MDF, and another step down to the junk sold in big box stores as MDF.
My current sub is 1/2 play with ceramic plates laminated inside, then 1/8 oak on the outside. Only 2 cubic feet but I can't lift one.
It sounds very cool but I think it is currently too complicated a project for me.As a table you should consider doing push-push woofers so as to greatly minimize box resonances by actively removing the driving force. So i would choose a couple 10” intead of a single 12”
While a BR will model as a lower cutoff do not forget room gain. I much prefer sealed for really low.
And the kick the driver, if one can make that difficult (a single woofer would be used down firing), here is a sketch i did of an isobarik push-push box with woofers hidden away.
It could be done with just a pair of woofers as well.
dave
Actually I was thinking of increasing the thickness, I still have to decide what material to use, usually for the speakers I use mdf and for the front baffle I make a double thickness sandwich with mdf and bamboo or plywood.
Brett,
True, but given the physics, and that in a woofer it is easy to move any resonances up above the bandwidth, it is WAY easier to do with quality plywood.
For instance a good sub can be built from 15mm quality ply. If you want o try to get the same performance out of MDF you are probably working with 25mm MDF.
Your back will thank you for not using MDF.
dave
True, but given the physics, and that in a woofer it is easy to move any resonances up above the bandwidth, it is WAY easier to do with quality plywood.
For instance a good sub can be built from 15mm quality ply. If you want o try to get the same performance out of MDF you are probably working with 25mm MDF.
Your back will thank you for not using MDF.
dave
I have tried to sandwich MDF, the pva glue seemed to soak in and expand the mdf on one side, so each board curved away from the other, leaving a gap around the outside edge. Perhaps a load of screws would have prevented this. I'd be tempted to make a double chamber aperiodic sub, preferably with opposed firing drivers. On the second last speakers I made, I used PLY for opposing sides, and layers of PLY for the other sides, so they look like VERY thick PLY.
Matrix brace an 18mm mdf build on 200mm centres and there'll be no resonances in or near sub BW. A bonus is a sheet of BB is about $300 here vs $38 for 18mm mdf.
Again, don't agree and I did a fair amount of testing of this with my accelerometer some years back. I see no reason to revisit as physics hasn't changed in the interim.
Edit: I generally build with 12 or 18mm MDF and brace with 12mm. Brace centres vary with the size and frequency range of the enclosure.
Not really relevant as I don't move subs or speakers often. Home speakers are not PA constantly being loaded in/out.