|   How LOW should you go ? | Tom Bombadil
Dec 10, 2002 3:18 PM | | What is people's opinion of recorded material (although by now NONE of it is "typical") content of Low Freq ?
What is your opinion of the lowest acceptable freq and associated SPL for a subwoofer ?
I was informed that 30 Hz was enough (and I really didnt think about SPL back then). |
| It all depends on... | Ray from RI
Dec 10, 2002 3:24 PM | | How much you want to spend? :D
A 32' pipe from the larger pipe organs produce a bass note of 16Hz, and is frequently recorded on organ CDs. I will think that's a good frequency to have it reproduced, though you're more likely to "feel" this note, and only "hear" its harmonies or 32, 48Hz, etc.
-Ray |
| Pipe organs | Richard Greene
Dec 10, 2002 4:12 PM | | If the organ has a 32' pipe which happens to be used during a song, the primary energy will be at the harmonics of 32Hz. etc. That's just the way organs are designed. The threshold of audibility at 20Hz. is about 75dB.
If the fundamental tone is below 20Hz. that portion of the sound would not be heard, just felt as pressure on your body.
Unfortunately in most homes loud sounds below 20Hz. tend to cause floors and walls to resonate which is a very annoying form of distortion.
I have heard many DIY subs capable of clean high output at 16Hz.,and even 12Hz. ... but very few commercial subs (unless placed in a very small room or in a car where there was lots of room gain / cabin gain -- 16Hz. is no big deal to obtain in a sealed car -- it's a very big deal to obtain in a large home listening room).
For example, I heard a Velodyne 18" sub that sounded clean at 16Hz., a Bag End 18" that played 16Hz. ... but not very loud ... or with a lot of harmonic distortion added when played loud. That's about it. I usually use test tones no lower than 20Hz. for testing subwoofers because lower tones usually cause very unpleasant noises. |
| 30Hz. for music in very small room / 20Hz. for A/V in large room | Richard Greene
Dec 10, 2002 3:56 PM | | A small well sealed room (150-200 square feet) can have 6 to 12dB of room gain at 20Hz. which will help compensate for a small sealed enclosure subwoofer with a -3dB point of 30Hz. Also, most music has limited output below 30Hz. -- pipe organ and some rap CDs are the primary exceptions.
A large room (over 400 square feet) will have little room gain at 20Hz. so your subwoofer gets no help from the room. If there are large openings into other rooms, there may be no room gain at all at 20Hz. If you listen to action movies there is likely to be lots of output below 30Hz. To create output at 20Hz. that's as loud as at 40Hz. requires a subwoofer driver to stroke four times as far. That's a very big deal and requires lots of large drivers, usually in ported enclosures, and usually aided by room corner placement. |
| The best Subs go below zero.. | Lance Boyles
Dec 10, 2002 4:43 PM | | These subs, rather than pound on your chest, such the breath out of your lungs. At excessively low freqs, the fluids in the body evaporate and one's skin turns to powder. The US Govt was working on a super low sub that could cripple troups in the field. You don't want to go that low. One guy here lost his thingy doing this and had to get a prothesis. |
| Fahrenheit or Celcius? (nt) | Kursun
Dec 11, 2002 7:21 AM | | |
| That's a good point... | Tom Bombadil
Dec 11, 2002 8:33 AM | | That one can really go too far and basically ask for too much.
But to the not so technically inclined it is hard to appreciate what real life sounds correlate to what frequency.
I agree that it is a spoon-feeding kind of question - rather than read a stack of books - but I bought a Sub because of a deal and definitely have the cart far ahead of the horse...
PS:
Hope that prosthesis works for your "friend" :) |
| How is a negative cycle per second possible? -nt | RUSSIA
Dec 11, 2002 4:18 PM | | |
| Maybe he's dyslexic. :) (nt) | WmAx
Dec 11, 2002 7:56 PM | | (nt) |
| by flipping the phase switch on the back of the sub? :) -nt | Kursun
Dec 12, 2002 7:20 AM | | |
| It may be a good idea... | Kursun
Dec 12, 2002 7:36 AM | | for the army to also work on a servo-superlow sub that changes its frequency and phase relative to the waves on field, to neutralize it. Watch out for standing waves though! :) |
| Something like this? a link, gtg back to school now :( -nt | RUSSIA
Dec 12, 2002 9:10 AM | | http://international.jbl.com/home/products/product_detail.asp?ProdId=TI-KSUB/230&SerId=TIK&language=ENGLISH |
| Ignore my last post, here is the link... | RUSSIA
Dec 12, 2002 4:58 PM | | there should not have been the "-nt" there!
http://international.jbl.com/home/products/product_detail.asp?ProdId=TI-KSUB/230&SerId=TIK&language=ENGLISH
--Michael |
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