Hi,
I am long time lurker in subwoofer thread, but that is all the knowledge I have. The subwoofers I ever used were those pathetic from 2.1 computer systems. Now it is a time for me to build my own DIY one.
My requirements are:
-Adequate box size. I am thinking about 6-8 inch drivers, so if there is very similar result - I prefer smaller size box
-f3 ~35Hz. The lower - the better. Can be a little higher if that makes box a lot smaller.
-No stamped steel speaker drivers. This one is pretty much the only "hard req" - please do not flame about this. Thank you.
-Would like to spend no more than 120EUR for driver. It has to be available in EU. Yes, I know, Dayton is pretty much out of my range.
Preference to SQ over SPL, still haven't decided if it will be powered by plate amp or will be passive. The only plate amp in my budget range is Monacor 200D, that is ~200W, but I doubt that I will ever use more than 50W.
That is pretty much it.
What box type, size and what driver should I look at?
As I understand I should look for some woofer-but-not-so-subwoofer divers with decent Xmax and then think about the box?
Look at only pure subwoofer drivers?
SB23MFCL45-4 is a little too expensive and probably will result in too big box. Right?
I am long time lurker in subwoofer thread, but that is all the knowledge I have. The subwoofers I ever used were those pathetic from 2.1 computer systems. Now it is a time for me to build my own DIY one.
My requirements are:
-Adequate box size. I am thinking about 6-8 inch drivers, so if there is very similar result - I prefer smaller size box
-f3 ~35Hz. The lower - the better. Can be a little higher if that makes box a lot smaller.
-No stamped steel speaker drivers. This one is pretty much the only "hard req" - please do not flame about this. Thank you.
-Would like to spend no more than 120EUR for driver. It has to be available in EU. Yes, I know, Dayton is pretty much out of my range.
Preference to SQ over SPL, still haven't decided if it will be powered by plate amp or will be passive. The only plate amp in my budget range is Monacor 200D, that is ~200W, but I doubt that I will ever use more than 50W.
That is pretty much it.
What box type, size and what driver should I look at?
As I understand I should look for some woofer-but-not-so-subwoofer divers with decent Xmax and then think about the box?
Look at only pure subwoofer drivers?
SB23MFCL45-4 is a little too expensive and probably will result in too big box. Right?
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Hofmann's Iron Law: low response, efficient, or small-pick two 
What's an "adequate box size", and what's too big for you?
Without EQ, getting an f3 ~35Hz is not going to happen with an inexpensive driver in a small box.
The Monacor 200D has no adjustable EQ, just a fixed boost ~+3dB at 40Hz.
The SB Acoustics SB23MFCL45-4 specs are good for what you seem to want to do.
It has 12mm Xmax (24mm peak to peak), and an Fs of 27Hz, in a 0.5 cubic foot (14 liters net) the F3 is ~ 65Hz.
It would require near +10dB (ten times the power..) to lower the f3 to 35Hz.
In a 28 Liter (net) ported box it could get near the same response with no boost.
The Alpine S-Series subs may be a good option, similar performance, and perhaps lower price, not up on what's available in Lithuania.
Oops, they have a steel frame.
Cast frames aren't inexpensive..
What's an "adequate box size", and what's too big for you?
Without EQ, getting an f3 ~35Hz is not going to happen with an inexpensive driver in a small box.
The Monacor 200D has no adjustable EQ, just a fixed boost ~+3dB at 40Hz.
The SB Acoustics SB23MFCL45-4 specs are good for what you seem to want to do.
It has 12mm Xmax (24mm peak to peak), and an Fs of 27Hz, in a 0.5 cubic foot (14 liters net) the F3 is ~ 65Hz.
It would require near +10dB (ten times the power..) to lower the f3 to 35Hz.
In a 28 Liter (net) ported box it could get near the same response with no boost.
The Alpine S-Series subs may be a good option, similar performance, and perhaps lower price, not up on what's available in Lithuania.
Oops, they have a steel frame.
Cast frames aren't inexpensive..
If you want a small box and low price, then you should be looking at exclusively at subwoofer drivers. If MFCL45 is too expensive then I can't help with that, but it's an excellent sub driver and it's box will be relatively small. You should read manufacturer's recommendations and use speakerboxlite and loudspeakerdatabase to gauge the box size and performance.
Regular woofers have weak motors that require a big box to hit low. They have higher sensitivity and lower inductance which helps with higher end of the bandwith but for sub-100Hz output you should focus on a 6-8" sub. You should expect something like 40Hz f3 from a reasonable box.
If your room is small then you may want to consider a sealed box and use some software to gauge the room gain down low.
Subwoofers tend to drink a lot of power even with a slight turn of the volume knob. Small drivers are laughably inefficient below their resonance and since you want to keep the box small, you should lower your expectations. 200W is not a lot, but 35Hz f3 is quite low actually. Maybe try to find a used driver.
I can see some drivers from Wavecor and SB discounted on Polish marketplaces so it should be possible for you to find something nice.
Regular woofers have weak motors that require a big box to hit low. They have higher sensitivity and lower inductance which helps with higher end of the bandwith but for sub-100Hz output you should focus on a 6-8" sub. You should expect something like 40Hz f3 from a reasonable box.
If your room is small then you may want to consider a sealed box and use some software to gauge the room gain down low.
Subwoofers tend to drink a lot of power even with a slight turn of the volume knob. Small drivers are laughably inefficient below their resonance and since you want to keep the box small, you should lower your expectations. 200W is not a lot, but 35Hz f3 is quite low actually. Maybe try to find a used driver.
I can see some drivers from Wavecor and SB discounted on Polish marketplaces so it should be possible for you to find something nice.
Reckhorn sub drivers are not expensive and have cast frames.
6.5":
https://reckhorn.com/en/speaker/speaker-chassis/167/d-165i-subwoofer-built-in-loudspeaker?c=119
8":
https://reckhorn.com/en/speaker/speaker-chassis/243/d-200-subwoofer-built-in-loudspeaker?c=119
6.5":
https://reckhorn.com/en/speaker/speaker-chassis/167/d-165i-subwoofer-built-in-loudspeaker?c=119
8":
https://reckhorn.com/en/speaker/speaker-chassis/243/d-200-subwoofer-built-in-loudspeaker?c=119
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Oops, this went wrong! Here is the correct url link:
https://reckhorn.com/en/speaker/speaker-chassis/167/d-165i-subwoofer-built-in-loudspeaker?c=119#
Dear weltersys,Hofmann's Iron Law: low response, efficient, or small-pick two
What's an "adequate box size", and what's too big for you?
Definitely low resp and small.
Probably thinking about ~40-45 Liters internal volume as upper limit, that is 1.4-1.6 cu ft for imperial units friends.
If the difference is very small, 30-35 Liters is optimal
This is still a budget build. If 35Hz is not easy achievable - 40Hz is also ok. This plate amp is pretty much the only option for this build... The other is to put DSP somewhere in the way of the sound, but for now I want to avoid that. I am still playing with PC based equalizers, and not at the level to go for full DSP. Also an option is to look for cheap chinese amp with 3 channels output, but they seem to lack subwoofer controls, like phase, cut freq and so on.
That fixed boost at 40Hz probably is exactly what I need, right?
8 inch is much more what I need. IMO F3 65Hz is not worth the effort and ~300EUR on parts alone...
I can easy live with 40 Liters box if that will get me to 40Hz
Thanks for advice, but Alpine series you mentioned is not available here. SWG series is in my budget, but they are steel frame. Everything from car audio up to 120EUR is stamped steel, also very very little tech data available. Do not want to play lottery.
Cast frame is pretty much the only hard limit.
rhalf,
Thanks for reply. No, buying used is not an option. Maybe if something available to see and check in person locally to drive with car, but I seriously doubt that.
If MFCL45 is the driver of choice AND 40Hz f3 is the new target - is 40Hz achievable?
I tried to play with speakerboxlite... Do not understand that program at all...
If it is to paint the box, that is not a problem, I can design box with CAD easily.With WinISD I get this result:
MFCL45-4
Vented, 40L box, 38Hz tuning, vent diameter 10cm, vent length 33.3cm.
Vented, 40L box, 35Hz tuning, vent diameter 10cm, vent length 40.6cm.
Vented, 30L box, 35Hz tuning, vent diameter 10cm, vent length 56.6cm. Attached
WinISD shows cone excursion limit at this tuning is ~25Hz at 100W.
Seems too good to be true. I made mistake somewhere in driver parameters or WinISD is not suitable to calculate boxes?
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GM,
From your pictures I see that:
Vented 30 Liters, ~36Hz, 0.5% efficiency
Closed 30 Liters, ~36Hz, ~0.3% efficiency
Does that mean, that I will lose Watts or just that the slope of the closed box is not suited at all without DSP?
In other words: vented box is the only option with simple plate amplifier in reasonable size able to play low Hz?
From your pictures I see that:
Vented 30 Liters, ~36Hz, 0.5% efficiency
Closed 30 Liters, ~36Hz, ~0.3% efficiency
Does that mean, that I will lose Watts or just that the slope of the closed box is not suited at all without DSP?
In other words: vented box is the only option with simple plate amplifier in reasonable size able to play low Hz?
this was discussed in a german forum: Winding height seems to be 24 mm and 8 mm is the magnet gap height.
So up to 8 mm (1way) excursion the voice coil remains in the magnet gap.
I think you can find some posts about D165 here on diyaudio. But these drivers are probably not well known outside germany.
Depending a bit on how cheap you can find the SAM-200D, I'd consider using a cheap SMPS brick (or a board) and something like a mono TPA3255 board instead and putting the saved money on the driver.
I would also not hesitate using DSP. TinySine TSA1701 for example is pretty damn good value. But considering the SB23 seems quite ideal for your needs and sits comfortably in 30 liters or so vented, that would be even better value
I would also not hesitate using DSP. TinySine TSA1701 for example is pretty damn good value. But considering the SB23 seems quite ideal for your needs and sits comfortably in 30 liters or so vented, that would be even better value
Yes, it may be a little cheaper, but the Monacor plate is ~130EUR, if I opt to go with separate components and put them into some nice aluminium "control box" - it will be much more fun but even more expensive.
Thank you for showing that DSP. 20EUR for DSP is a good deal.
For this project I am leaning towards plate amp. Even the simplest one will have everything I need.
Now I am looking into reviews of Reckhorn drivers. I think the choice will be between them and that SB.
Sofa is in the middle of the room, alternate dimensions and types like transmission line will be much bigger. Simple cube, golden section or smth in between is the way to go.
Thought about more small woofers - there are pretty much no advantage here: it will cost more, will have similar or even smaller Sd and Xmax and most important - there no subwoofer drivers in my price range which are small, except that Reckhorn 165
