I want to use a SS 18W8545k as a sub and it doesn't move enough air in a closed box. I like the sound of high efficiency boxes but I'm not looking for a full sized horn and I want f3 lower than 35Hz.
I've been duelling with hornresp for a couple of hours trying to get a useable response in a tapped horn but I can't find one, maybe it's just me or maybe this driver is no good and nothing I do will get it working in a tapped horn?? Should I keep trying with the tapped horn or try another enclosure?
I've been duelling with hornresp for a couple of hours trying to get a useable response in a tapped horn but I can't find one, maybe it's just me or maybe this driver is no good and nothing I do will get it working in a tapped horn?? Should I keep trying with the tapped horn or try another enclosure?
Hi
As a counter weight to David's IMO well done TH design a T-TQWT is presented here: See picture 1(2).
The T-TQWT has lower FR cut-off and uses less volume /length and is IMO far easier to damp and filter for good SQ above and below 80 Hz.
If equalized to flat pass band the TH will only gain 2.3 dB compared to the T-TQWT: See picture 2(2).
b
1(1)
As a counter weight to David's IMO well done TH design a T-TQWT is presented here: See picture 1(2).
The T-TQWT has lower FR cut-off and uses less volume /length and is IMO far easier to damp and filter for good SQ above and below 80 Hz.
If equalized to flat pass band the TH will only gain 2.3 dB compared to the T-TQWT: See picture 2(2).
b
1(1)
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AndrewT, I might have done that if I couldn't get a tapped horn to work, but thanks.
rcavictim, it's doesn't say sub on the box. Maybe I shouldn't have called it that but I want to cross over below 100Hz.
David_Web and bjorno, so it can be done. I can now see I was looking at it the wrong way but now the TH is back on
GM, I suppose I could stretch a few cubic feet or so if it was worth it. What did you have in mind?
rcavictim, it's doesn't say sub on the box. Maybe I shouldn't have called it that but I want to cross over below 100Hz.
David_Web and bjorno, so it can be done. I can now see I was looking at it the wrong way but now the TH is back on
GM, I suppose I could stretch a few cubic feet or so if it was worth it. What did you have in mind?
AllenB said:
IMO sub-bass only occurs in the first octave (20-40Hz) and a bit below. From 40 Hz up is the realm of a regular woofer. Others might argue that the range described by sub-bass is actually the region below hearing which many texts believe to be 20 Hz.
It is pretty much impossible to move enough air much below 40 Hz to be usefully audible with a tiny driver only measuring 7" frame size. The piston is what maybe 5" diameter to the middle of the surround? It is absolutely impossible to move enough air to be heard at 20 Hz with such a small driver.
Low frequency loudspeakers have to be large. You can make up for lost diameter with increasing excursion up to a point but early on along this path you start seeing the rise of harmonic distortion and 'chuffing' sounds, neither which are related to high fidelity.
The concept of hi-fi seems to have been lost by the modern music and sound reproduction industry. My proof is the popularity of MP3 files and equipment that uses only that highly compressed format being the most encountered. Companies that market home theater in a box will sell you a 1000 watt!!! (more like 1000 milliwatts) system that has six tiny speaker boxes and runs on a wall wart. People have been told through marketing so long that is is the hot sh*t that they believe it. It is all you can find in the stores where the majority of well programmed , dutifull consumer sheeple shop. The companies can sell underperforming crap and laugh all the way to the bank. The only thing that matters any more is the shareholders and the fat CEO salary and bonuses. Customer satisfaction? If you aren't satisfied with our product, you must be using it wrong.
Please do not think I was picking on you at all Allen. It is just that with what you just read all bottled up inside me, when I read 7" and subwoofer in the same sentence it kinda' hit a nerve.
Why are the rest of you here who really do know better leading Allen on?
Allen, you want low bass, sub-bass? Be prepared to buy some large drivers and make a lot of sawdust.
rcavictim said:
I have a better question, why are you erroneously slandering me? I didn't offer to design a true 'sub' design or lead him on in any way that what I presented would be capable of 'sub' BW output at any usable amplitude.
This driver's specs is more than capable of true <20 Hz sub duty at audible levels in a typical HIFI/HT app, it just has to be in a medium small room size horn, so hardly 'impossible', just a poor choice for the app.
GM
GM said:
GM, with my words "the rest of you here", I actually wasn't pointing at you so much as the group of lurkers here who have read this post and know I am right but have not chimed in and said anything along the lines of the point I was trying to make. They are guilty by their silence. I know that you are one of the advanced contributors here with lots of hands on with some large speakers and I enjoy reading your contributions.
rcavictim, I can see where you're coming from. I even think it's the reason I want to build my own. I like the way it used to sound all the way up to and including the eighties but only the good eighties stuff, not the cheap stuff.
What I'm looking for is a woofer, I know that much and I appreciate that others here have answered my question AND I appreciate that you have set me straight.
GM, I tried your design and it has more sensitivity and more extension, nice. Would you expect the crossover to take down the bump at 70Hz or isn't this going to be noticeable and could I cross it over on 100Hz if I chose to? I think this level and f3 would be good enough for what I want.
What I'm looking for is a woofer, I know that much and I appreciate that others here have answered my question AND I appreciate that you have set me straight.
GM, I tried your design and it has more sensitivity and more extension, nice. Would you expect the crossover to take down the bump at 70Hz or isn't this going to be noticeable and could I cross it over on 100Hz if I chose to? I think this level and f3 would be good enough for what I want.
Right, bigger box = more acoustic gain.
No personal experience yet, but if you browse the TH threads you can find a number of measured THs that show a much more muted response than simmed and damping the throat area will smooth it out even more, just like with a TL, so combined with the XO it shouldn't be a problem. Regardless, in a typical ~8 ft high room there's a null in the 70-80 Hz BW, so some peaking here can be advantageous.
GM
No personal experience yet, but if you browse the TH threads you can find a number of measured THs that show a much more muted response than simmed and damping the throat area will smooth it out even more, just like with a TL, so combined with the XO it shouldn't be a problem. Regardless, in a typical ~8 ft high room there's a null in the 70-80 Hz BW, so some peaking here can be advantageous.
GM
Small Drivers _ Impulse Response
Hi AllenB,
I don't really have time to chime in on the discussion, but I have to exercise my computer to try to find out if my new backup software (NTI Shadow, it came for free with a Toshiba USB harddrive) will actually at least kind of work on a Windows XP computer.
1. As to small drivers in subwoofers: there are quite a number of tapped horn examples for the TangBand W6-1139 6.5". When used in multiples, small drivers can be used successfully as subwoofers within the range you indicate, particularly in the home. The ones that come to mind without searching are in the Collaborative Tapped Horn thread, by Volvotreter, just_a_guy and littlemike. Also, something build around the general ideas of the TH-SPUD (8"dual drivers) can provide more than sufficient output for at least my home environment. I recommend geitmans thread (hopefully it has not been completely trashed up, yet ):
http://www.diyaudio.com/forums/showthread.php?threadid=134369
2. Keep an eye on the impulse response, using the impulse response tool in hornresp can give you a good idea as a starting point. After that, somebody will have to measure something someday.
3. I'll attach a hornresp simulation for a dual using the Scanspeak 18W8545K, including the impulse response. I won't have a lot of time to participate at the moment, but this might give you some ideas.
Now, back to Windows Explorer to see what happened in the shadows.
Regards,
Hi AllenB,
I don't really have time to chime in on the discussion, but I have to exercise my computer to try to find out if my new backup software (NTI Shadow, it came for free with a Toshiba USB harddrive) will actually at least kind of work on a Windows XP computer.
1. As to small drivers in subwoofers: there are quite a number of tapped horn examples for the TangBand W6-1139 6.5". When used in multiples, small drivers can be used successfully as subwoofers within the range you indicate, particularly in the home. The ones that come to mind without searching are in the Collaborative Tapped Horn thread, by Volvotreter, just_a_guy and littlemike. Also, something build around the general ideas of the TH-SPUD (8"dual drivers) can provide more than sufficient output for at least my home environment. I recommend geitmans thread (hopefully it has not been completely trashed up, yet
):http://www.diyaudio.com/forums/showthread.php?threadid=134369
2. Keep an eye on the impulse response, using the impulse response tool in hornresp can give you a good idea as a starting point. After that, somebody will have to measure something someday.
3. I'll attach a hornresp simulation for a dual using the Scanspeak 18W8545K, including the impulse response. I won't have a lot of time to participate at the moment, but this might give you some ideas.
Now, back to Windows Explorer to see what happened in the shadows.
Regards,
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