High aspect ratio slot port?
I don't really need lots of power below 30hz, but ofcourse it's fun sometimes to show off with some really deep bass like none of my friends have heard before.
So, you think the new SDX10 will play music nicely in a 50l 25hz box?
I don't really need lots of power below 30hz, but ofcourse it's fun sometimes to show off with some really deep bass like none of my friends have heard before.
So, you think the new SDX10 will play music nicely in a 50l 25hz box?
High aspect ratio slot port?
The Mar-Kel have high aspect ratio slot ports.
In a room, you will have a peak at the bottom of its passband.
Not huge. High aspect ratio.
The sims are anechoic. Add room gain at a 3-6/octave dB upward slope starting at somewhere between 70-100 hz and you end up with a big peak.
dave
The sims are anechoic. Add room gain at a 3-6/octave dB upward slope starting at somewhere between 70-100 hz and you end up with a big peak.
dave
Uhm, i don't know much about octaves really to be honest.
So you say i will end up with a massive peak or what? Or will a high aspect ratio slot port tame this peak?
So you say i will end up with a massive peak or what? Or will a high aspect ratio slot port tame this peak?
Every doubling or halving of frequency is an octave.
The high aspect slot port adds resistance making the response somewhere between what it looks like as a BR in the sim, and the response in the same volume sealed.
dave
The high aspect slot port adds resistance making the response somewhere between what it looks like as a BR in the sim, and the response in the same volume sealed.
dave
Ah, so it sounds like a BR but the driver think it's in a closed box?
What about a design like this but with a slot port? http://homepage.mac.com/planet10/CSS/ShadowSD12-NBVR-0v9-map.pdf
I like the design actually.
What about a design like this but with a slot port? http://homepage.mac.com/planet10/CSS/ShadowSD12-NBVR-0v9-map.pdf
I like the design actually.
Ah, so it sounds like a BR but the driver think it's in a closed box?
Nope. In between. Scott has taken the slot port and added a horn load at the end. I leave it to design those. If you chop off the horn you have what i was suggesting.
dave
Yeah, that ending makes the box quite much taller. And the woofer is side-mounted. I want to get the box as thin as possible being able to fit a CSS SDX10 (ver1 or ver2). So... How to get the right size of the port?
Take the port you have modeled (and model a fairly long one -- i usually try to get it close to one of the dimensions), and then take the cross-section of the port and change it to a rectangle... if you can get it as wide as the side that the vent fires out of and then as short a height as needed to fit the calculated xSection. For a woofer you probably want to keep it at least 2 cm high. You can add vent spacers to reduce the width if it is too long to fit the depth of the box without making it into an L.
An example attached
dave
An example attached
dave
Attachments
Well, i guess i will have to make it an L to be able to get the port to get to the front. The box will be max 40cm deep. Or wait... If i mount the woofer on the side i can still have the slot port at the front of the box.
While checking in WinISD i can have a port that is 250x30x604mm.
How wide does the box have to be to be able to fit a SDX10? Should the driver be placed as low as possible or as close to the Mar-Kel70 as possible?
One of the boxes will be placed in a corner and the other next to a door, anything i can do to even out the boost?
While checking in WinISD i can have a port that is 250x30x604mm.
How wide does the box have to be to be able to fit a SDX10? Should the driver be placed as low as possible or as close to the Mar-Kel70 as possible?
One of the boxes will be placed in a corner and the other next to a door, anything i can do to even out the boost?
There will be new SDX10 coming since Bob is almost out. I don't expect them to be significantly different.
In what way?
GM
In a room, you will have a peak at the bottom of its passband.
The question is where?
For example, mine's around 12 Hz, so is down where it doesn't matter even if it causes a technically under-damped alignment due to how we hear.
It can matter though if the peak is strong enough to resonate such things as TT tonearms, a problem I 'chased' for quite awhile since I had nothing that could measure it, ergo couldn't figure out for sure what was causing it until in desperation I moved the TT around the room until I found a large enough null along a side wall. Even then, I had to 'borrow' one of the wife's macrame' plant slings to suspend it from the ceiling...........
Rooms, ugh! I'm way past ready for the elastic bio-dome 'home of tomorrow' that was prophesied by the 21st century!
GM
How wide does the box have to be to be able to fit a SDX10?
Should the driver be placed as low as possible or as close to the Mar-Kel70 as possible?
One of the boxes will be placed in a corner and the other next to a door, anything i can do to even out the boost?
Don't know, look it up on the CSS site.
Ideally you want drivers to be < 1/3 WL apart (Pi is what I use) at the XO's -12 dB point to sum ~ as one large point source. For example, you use an 80 Hz/2nd order XO:
Since each order is a 6 dB octave increase in slope roll off, 2nd order is rolling off at 12 dB/octave, making the -12 dB point one octave away at 160 Hz. < 1/3 WL of 160 Hz then is ~34,400 cm/sec/160/pi = ~68.44 cm apart.
In this case, the (sub)woofer can be down at the floor for max boundary gain loading and the mids/HF can be up at ear height without sounding as two separate sound sources.
One really needs to measure these two different speaker locations at the listening position (Lp) since the doorway is acting as a large reflex port that is only 'active' over 'x' BW.
IME, a doubling of 'subs' by the door plus an acoustically large enough vertical baffle (narrow 'wall' extension gasketed to the room's wall) to make the mids/HF 'feel' a corner has worked well enough. That, or mass quantities of EQ to even them out with the obvious loss of system efficiency/dynamic headroom.
GM
Seems to be atleast 154mm to be able to fit the driver. 170mm when flush-mounted. So i guess it has to be around 200mm wide?Don't know, look it up on the CSS site.
Making the box 81x20x31.1 inside dimensions gives 50l. Having the box just 35.6cm deep (including 22mm material thickness) makes it possible to get a slot port at the front.
Ideally you want drivers to be < 1/3 WL apart (Pi is what I use) at the XO's -12 dB point to sum ~ as one large point source. For example, you use an 80 Hz/2nd order XO:
Since each order is a 6 dB octave increase in slope roll off, 2nd order is rolling off at 12 dB/octave, making the -12 dB point one octave away at 160 Hz. < 1/3 WL of 160 Hz then is ~34,400 cm/sec/160/pi = ~68.44 cm apart.
In this case, the (sub)woofer can be down at the floor for max boundary gain loading and the mids/HF can be up at ear height without sounding as two separate sound sources.So, you recommend placing it as close to the floor as possible?
Only "active" over "x" BW?One really needs to measure these two different speaker locations at the listening position (Lp) since the doorway is acting as a large reflex port that is only 'active' over 'x' BW.
So i will have to make a wall in my room? That will be impossible :SIME, a doubling of 'subs' by the door plus an acoustically large enough vertical baffle (narrow 'wall' extension gasketed to the room's wall) to make the mids/HF 'feel' a corner has worked well enough. That, or mass quantities of EQ to even them out with the obvious loss of system efficiency/dynamic headroom.
Hi Rullknufs,
If you are interested in good bass in a room, you need to read this thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html
,and particularly the link in Post #5 to get you started.
Regards,
If you are interested in good bass in a room, you need to read this thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html
,and particularly the link in Post #5 to get you started.
Regards,
Hi Rullknufs,
If you are interested in good bass in a room, you need to read this thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html
,and particularly the link in Post #5 to get you started.
Regards,
Thanks. I read the first 4-5 pages but didn't learn anything from that really :S
You suggest i should have another woofer to place randomly in my room somewhere?
????
dave
I gotta quit posting before the morning caffeine kicks in....... I read it simply as 'significantly different'............ 🙁
GM
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