Hello all,
I'm designing my first subwoofer around a 300 euro budget. It will run in a stereo 2.1 setup for music, in a small room. So my preference would be an f3 just below 30hz, keeping it small, and a focus on SQ rather than SPL.
I landed on the following components, but i'm open for suggestions:
Setting FS at 29Hz gives me the following TF in WinISD:
Adding filters:
Now, my question is is it safe to assume that the SPA-100D will HP roll-off around 23Hz? Because if I go below 22Hz we will hit Xmax at 100W. I will probably never use this amount of power, but it would be great to know my design can handle the full output available.
I have read a review of the monacor sam-200D, where the roll-off is desirable. So would I benefit from the 8Ohm version of the driver (Which has slightly worse properties?) and running the 200W amp to get a safe roll-off?
Excursion at 100W:
I designed a slot port for the full lenth of the cabinet, which means 2cm x 26,4cm and a lenth of 50cm. 2cm seems oddly small, but I assume it won't be a problem? Port resonance at 350Hz.
Air velocity at 100W:
Which is right around the recommended maximum.
So for fun I went to designing in fusion 360. The big cutout is for the plate amp. Is this the correct way to design a slot vent? I will add some bracing later.
As this is my first attempt, all general feedback is welcome. Regardless of the previous questions, would you think it is worth to design this sub for SQ music application instead of buying an entry level 300 euro sub or saving up for something like a rel t5x or svs sb1000? Please keep in mind that i don't have any way to measure and I dont have any way to EQ outside of APO.
Thanks in advance.
I'm designing my first subwoofer around a 300 euro budget. It will run in a stereo 2.1 setup for music, in a small room. So my preference would be an f3 just below 30hz, keeping it small, and a focus on SQ rather than SPL.
I landed on the following components, but i'm open for suggestions:
- sb acoustics sb23mfcl45-4 (I assume the 4Ohm version is preferable) - 140 euro
- Dayton SPA-100D (or monacor SAM-200D for double the power if necessary, same price) - 145 euro
Setting FS at 29Hz gives me the following TF in WinISD:
Adding filters:
Now, my question is is it safe to assume that the SPA-100D will HP roll-off around 23Hz? Because if I go below 22Hz we will hit Xmax at 100W. I will probably never use this amount of power, but it would be great to know my design can handle the full output available.
I have read a review of the monacor sam-200D, where the roll-off is desirable. So would I benefit from the 8Ohm version of the driver (Which has slightly worse properties?) and running the 200W amp to get a safe roll-off?
Excursion at 100W:
I designed a slot port for the full lenth of the cabinet, which means 2cm x 26,4cm and a lenth of 50cm. 2cm seems oddly small, but I assume it won't be a problem? Port resonance at 350Hz.
Air velocity at 100W:
Which is right around the recommended maximum.
So for fun I went to designing in fusion 360. The big cutout is for the plate amp. Is this the correct way to design a slot vent? I will add some bracing later.
As this is my first attempt, all general feedback is welcome. Regardless of the previous questions, would you think it is worth to design this sub for SQ music application instead of buying an entry level 300 euro sub or saving up for something like a rel t5x or svs sb1000? Please keep in mind that i don't have any way to measure and I dont have any way to EQ outside of APO.
Thanks in advance.
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Should work just fine
This is what I put together:
It's Dayton Audio DCS205-4 in a 34 liter slot ported box tuned to 32Hz. Slot is 25x350x710mm. Box is built with 18mm birch ply with double stacked baffle. The only thing I would do different is I would brace the hell out of the box.
The pictured measurment should be taken with a grain of salt since it's measured with a handheld smart phone and imm6 mic without calibration. But gives the Idea what's coming out of that box.
The driver should reach xmax at 90W and put out 107db IIRC (should have a look those sims agai)
This is what I put together:
It's Dayton Audio DCS205-4 in a 34 liter slot ported box tuned to 32Hz. Slot is 25x350x710mm. Box is built with 18mm birch ply with double stacked baffle. The only thing I would do different is I would brace the hell out of the box.
The pictured measurment should be taken with a grain of salt since it's measured with a handheld smart phone and imm6 mic without calibration. But gives the Idea what's coming out of that box.
The driver should reach xmax at 90W and put out 107db IIRC (should have a look those sims agai)
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I'd also put round overs on those 3 edges to minimise turbulences and somehow apply a radius in that corner of the slot
Yes, the red graph is the measured frequency response and no, there is no EQ or DSP involved. I'm using my PC with audigy fx soundcard as a source and cheap ayima tpa3255 amplifier.
I have yet to measure the FR in the room
Correct me if i'm wrong but that would mean f3 is at 57Hz and 30Hz would be -11dB. That doesn't seem to be worth the effort, considering that I don't have dsp to boost the extension. Is sealed that much of a SQ improvement?
I have also read that closed subs prefer a higher Qts and as this driver is around 0.344, wouldn't it make sense to buy another driver altogether?
Well that complicates things, so my original design will probably have a significant boom due to room gain, as I will be placing it in a corner.
I was going to say the same thing about your alignment, but thot it had already been built.
It should be tuned lower so that you have a long, smooth roll-off. On your sim the timy bit at teh bottom where the FR curves first derivative passes thru zero twice will have at least some “booming”. And that will ve exacerbated by corner placement.
First round fix, tune them lower.
dave
I'd say design the box so you don't have to bend the vent.
Have a look at the "Boom Unit" design on my website (see link below) for an example of how the box can be designed to remove the need for a bent vent. Yes, it's a MLTL, but that's basically a vented box with consideration given to what happens to the harmonic resonances. ...
http://www.diysubwoofers.org/projects/home/boomunit/
Have a look at the "Boom Unit" design on my website (see link below) for an example of how the box can be designed to remove the need for a bent vent. Yes, it's a MLTL, but that's basically a vented box with consideration given to what happens to the harmonic resonances. ...
http://www.diysubwoofers.org/projects/home/boomunit/
If your box size is 30*30 why not go to a 250mm driver and take advantage of the usually lower Fs and greater SPL?
Just use a stuffed sealed box?
How are you handling the crossover to the sub ?
Just use a stuffed sealed box?
How are you handling the crossover to the sub ?
Thank you all so much for your input, I will redesign to produce a smoother roll off and probably reduce the box size a bit. And post my results here again.
Good question, the driver itself is 234mm in diameter, so the minimum size would be 270mm, I just left a bit of margin to get to 34L. I don't really need better Fs and SPL, I rather reduce the box size a bit.
I wasn't planning on adding a crossover, relying on the plate amp provide the LP and HP filters. Is that a problem?
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It isn't if the plate amp has decent XO facilities, I didn't think that amp had any tho, but I've been wrong many times before
I would suggest placing the woofer on the side instead of bottom. Otherwise it will sag over time and voice coil get missaligned out of the gap. Your calculations will be off.
The HiPass in most plate amps is not much use. With a plate amp you usually just dial it in REL-Style. ie mains run all the way down and the sub(s) are feathered in below.
dave
I've used this woofer and like it, but found that it liked a fair amount of power. I think mine was .75 cu ft tuned to 32hz or there abouts with a 300 watt plate amp.