Cameron Glendin said:
I still say that's total B.S.
Think about it. If you needed a certain amount of space to recreate a certain bass frequency, then you wouldn't hear anything below 2000Hz with headphones and probably nothing below 60Hz in an average sized room.
I have been to plenty of pipe organ recitals over the years, not to mention going to churches, music halls and colleges tuning pipe organs with my father for years. I'm quite aware of what "real" low bass frequencies sound like and how they load a room/building. I am also quite aware that my subwoofer in my room comes very darn close to the real thing within reason. It measures flat to 12Hz, and I can hear pretty good down to 16Hz on my own.
An instrument may need to be a certain scale, size and length to produce a certain bass frequency, but a driver and/or room does not.
pinkmouse said:
Agree completely!
Cameron Glendin said:
Planar wave generation is a fascinating subject, but has absolutely nothing to do with room size. If your hypothesis were correct, all film mixdown studios would have to be the size of the average cinema auditorium, whereas most are about the size of a large living room.
Yes, but they act to increase the size of the apparent horn loading to support lower frequencies and increase efficiency, again nothing to do with room size.
Back on topic...
What software would you use to design a below 40hz monster sub?
Is Unibox's models accurate enough for vented?
And what software is capable of doing a transmission line prediction?
(BTW... will try GM's TL and my own vented and let my friend pick the one that he likes better)
What software would you use to design a below 40hz monster sub?
Is Unibox's models accurate enough for vented?
And what software is capable of doing a transmission line prediction?
(BTW... will try GM's TL and my own vented and let my friend pick the one that he likes better)
I have never said that, my issue is about distortion. Its really not a hard concept. Very hard to doubt when you have heard the difference demonstrated.
Seeing the same movie in a huge 1000 seat cinema is certanly a different experience to seeing it in a 100 seat cinema. Not that the experence isnt good in the smaller screen, just different and give me the bigger venue anyday.
I still can not believe you if your saying that listening to a recording of an organwork featuring a note from a 64ft or perhaps 110 ft long pipe sounds/feels exactly like experiencing it in your living room. I dont doubt that your living room would/could sound amazing, just not EXACTLY the same as the original church or town hall it was recorded at.
As for plain wave fronts, if you were to mount your speaker flush into your brick walled or super thick multi panneled acoustic gyprock walled house, the effect would be more realistic sounding than that speaker in any timber box.
Cameron Glendin said:
If you need to fill a larger venue, then you're most likely going to be running into more distortions with multi arrays of speakers and gobbs of amplifier power.
As for the low CCCC 64ft stop (8Hz) on a pipe organ (which there are few), my system falls a little short on keeping up. However, a lot more pipe organs that have a low CCC 32ft stop (16Hz)... Well my system is quite capable of that range.
And just to clear up something, I never said anything being "EXACTLY", I said "my subwoofer in my room comes very darn close to the real thing within reason"
Anyway, that's all I wanted to say.
This is directed to everyone who has experience with lower than 25hz audio frequencies.
I am interested those frequencies. I have never heard a deeper one than 20hz, as my TH sub quickly lost output below 22hz and my mains have trouble below 40hz. How much does it add to music and movies, to have even lower frequency response? A 20hz sine wave was rather a feeling of pressure, (which could modulate my voice in funny ways) than a tone one could hear. Does this trend towards more feeling and less hearing continue towards lower frequencies? Those questions are directed at subjective experience, so please tell me yours.
I am thinking of building a 10-40hz TH as a new sub and try to evaluate if it will be a rewarding diy venture, compared with a 20-80hz TH. I consider myself quite fascinated by low bass, but i wont build it, if there is nothing i can feel or hear below 20hz.
I am interested those frequencies. I have never heard a deeper one than 20hz, as my TH sub quickly lost output below 22hz and my mains have trouble below 40hz. How much does it add to music and movies, to have even lower frequency response? A 20hz sine wave was rather a feeling of pressure, (which could modulate my voice in funny ways) than a tone one could hear. Does this trend towards more feeling and less hearing continue towards lower frequencies? Those questions are directed at subjective experience, so please tell me yours.
I am thinking of building a 10-40hz TH as a new sub and try to evaluate if it will be a rewarding diy venture, compared with a 20-80hz TH. I consider myself quite fascinated by low bass, but i wont build it, if there is nothing i can feel or hear below 20hz.
Also, anyone tried this design?
http://www.billfitzmaurice.com/THT.html
"Add in the cabin gain of an average room (12dB per octave below 30 Hz) and you end up with flat response to 1Hz with 110dB sensitivity."
http://www.billfitzmaurice.com/THT.html
"Add in the cabin gain of an average room (12dB per octave below 30 Hz) and you end up with flat response to 1Hz with 110dB sensitivity."
Thanks for the replies so far,
yes i hear alot of experimental electronic music with digitally generated tones and i think (judging by the cone movement without highpass filter of the woofers) there is significant content below 25hz. I remember a post from Tomas Danley, where he spoke about the importance of a woofer which can get well below the fundamental of a bass (the instrument, not the tonal area) to get a real feeling of it. So maybe a deep response is also nice for acoustic music.
I have not tried this design, but i generally dont count on room gain. My current setup uses 4 12inch PA woofers in closed boxes, which should be flat to DC if i had room gain, since they are closed boxes and have quite some volume displacement capability. But in reality, they start to get trouble below 50hz and 30hz is the maximum i can get out of them before there is too much distortion at home listening levels. So i think this design needs a special room for it. My music room has concrete walls room and is in a basement, so i figured there should be enough room gain, but there isnt. Doors and windows probably leak too much. I fear, that room gain is more wishfull thinking than reality.
yes i hear alot of experimental electronic music with digitally generated tones and i think (judging by the cone movement without highpass filter of the woofers) there is significant content below 25hz. I remember a post from Tomas Danley, where he spoke about the importance of a woofer which can get well below the fundamental of a bass (the instrument, not the tonal area) to get a real feeling of it. So maybe a deep response is also nice for acoustic music.
I have not tried this design, but i generally dont count on room gain. My current setup uses 4 12inch PA woofers in closed boxes, which should be flat to DC if i had room gain, since they are closed boxes and have quite some volume displacement capability. But in reality, they start to get trouble below 50hz and 30hz is the maximum i can get out of them before there is too much distortion at home listening levels. So i think this design needs a special room for it. My music room has concrete walls room and is in a basement, so i figured there should be enough room gain, but there isnt. Doors and windows probably leak too much. I fear, that room gain is more wishfull thinking than reality.
I see what you are saying, you can never rely on room gain.
It may be worth looking into horn designs tho, as they often tend to go lower than the Fs of the driver. I've seen a driver with an Fs of 45 go down to 30Hz with a good horn enclosure, so a driver with an Fs of 20Hz and a suitable horn enclosure would maybe good for 15 or even 10Hz?
The box would have to be big tho...
It may be worth looking into horn designs tho, as they often tend to go lower than the Fs of the driver. I've seen a driver with an Fs of 45 go down to 30Hz with a good horn enclosure, so a driver with an Fs of 20Hz and a suitable horn enclosure would maybe good for 15 or even 10Hz?
The box would have to be big tho...
AndrewT said:
with tapped horns, you need a horn maybe 8 to 10 meters long to achieve -3db at 10hz. with the right driver this can be done in a few hundred liters of box.
@ fizzard: normals rooms have losses, because they are not completely sealed. If they are completely sealed you would suffocate sooner or later
but before the point of your death, you would have a true 12db rising slope per octave of lower frequency. this would result in flat response down to dc. you can imagine a near dc tone as a pressure rise in the room, because the membrane makes the room volume slightly smaller as it pushes forward or slightly bigger as it moves into the box. a similar effect to weather or diving, but much more subtle.@ despotic931: i have heard one, better to say i could feel it. it was subtle, despite my voice being modulated alot because of the loud volume. but it was definitely a thing i dont want to miss in audio.
@ MikeHunt79: Thats true, front loaded horns do this, depending on the design, they even have response below their horn gain cutoff frequency just like a sealed box. I am for tapped horns as subwoofers because they can be alot smaller than front loaded ones. but they unload below their low cutoff frequency, so they cant play to dc. but i think below 10hz a normal house would get structural problems before i could hear / feel the tone.
MaVo said:@ fizzard: normals rooms have losses, because they are not completely sealed. If they are completely sealed you would suffocate sooner or later
Are you sure you're not picking up another roll-off as the frequency approaches zero? One not related to imperfect seal.
I think of the perfectly sealed room as a volume with a certain number of air molecules in it. if the volume gets smaller, the pressure gets bigger, as is shown in the gas law: pv = nRT (nRT is constant in our case). This model doesnt have another mechanism which could cause a rolloff, but describes a gas completely within some accuracy limitations. Ok that was the long answer, the short is, i know no such mechanism
MaVo said:
I only bring it up because many people dont realize the SPL that must be attained to allow a 20hz sine wave to sound as loud to the human ear as say a 200hz sine wave.
http://en.wikipedia.org/wiki/Equal-loudness_contours
I'm not for or against going down to 20hz, or even lower for HT use, I'm just a spectator in this conversation, curious where it will go. I can tell you I have only hear one HT setup that went down to 20hz, and it sounded terrible, way too many peaks in the frequency response of the sub, I personally would have rather done without it on that system.
-Justin
despotic931, this equal loudness contour is an interesting thing. I never bothered looking further into it, but to have a subjectively linear speaker, one should take it into account. On moderate volumes i allways boost the <100hz frequencies by some db because it sounds better to me. But maybe i just like bass
Many people do not realize that our ear does not hear all frequencies at the same volume, here is another thing to read...
http://en.wikipedia.org/wiki/Fletcher-Munson_curves
This is the actual reason for the "loudness" button on your average store bought shelf system. The "loudness" is supposed to be engaged when listening at lower level, and boosts the bass and treble frequencies to a point where they are as audible as they are when listening at higher levels (if you look, the higher the spl, the more the curves flatten out)
I guess the whole point I'm trying to make is that people are saying they want 20hz at 90db, and I am wondering if they realize that this is not going to have the same effect, or volume, as 40hz at 90db.
-Justin
http://en.wikipedia.org/wiki/Fletcher-Munson_curves
This is the actual reason for the "loudness" button on your average store bought shelf system. The "loudness" is supposed to be engaged when listening at lower level, and boosts the bass and treble frequencies to a point where they are as audible as they are when listening at higher levels (if you look, the higher the spl, the more the curves flatten out)
I guess the whole point I'm trying to make is that people are saying they want 20hz at 90db, and I am wondering if they realize that this is not going to have the same effect, or volume, as 40hz at 90db.
-Justin