Frequency Analysis of a Drum kit: 24" kick drum; 6", 8", 10", 12", 13", 14", 15", 16" toms
Lowest fundamental = 52 Hz
Below that just noise with room rumble
Conclusion: Best SNR improvement for acoustic music = high pass/rumble filter at 40 Hz
OB bass looks good for acoustic music given the lack of music under 40Hz and that the low bass is appreciably down in SPL compared to mid bass, more then compensating for the OB -6dB roll off.
Lowest fundamental = 52 Hz
Below that just noise with room rumble
Conclusion: Best SNR improvement for acoustic music = high pass/rumble filter at 40 Hz
OB bass looks good for acoustic music given the lack of music under 40Hz and that the low bass is appreciably down in SPL compared to mid bass, more then compensating for the OB -6dB roll off.
Your theory is on point. No disputing it. However, try listening to a true full range recording with and without a subsonic filter - ie 30 Hz @ 4th order HP. I guarantee you there will be a significant noticeable difference in how the low end sounds. Subsonic filters absolutely destroy low end integrity. In live sound HP filters are vital, but in a studio recording where everything is isolated, a strict DC blocking filter (usually digital) that doesn't impart significant phase shift and HP around 5 Hz. Thats it, unless theirs noise and other junk. I'm a bassist and can tell you a highly skilled player will be able to play clean without any unmuted string rumble.
So even if your system isn't capable of lower than 40 Hz reproduction, you still need to have the phase integrity of the signal way down past 20 Hz to not destroy the low end attack. Your LF driver and crossover are already imparting phase shift past Fc. I can guarantee you there will be noticeable degradation in LF quality (including attack and slam, etc) if you further HP the signal. It will be noticeable, even on an open baffle setup or other fullrange dipoles. Even though the spectrum analysis you show doesn't indicate content past 41 Hz for a double bass or lower than that for kick drums, the attack of the waveform still has much lower infrasonic content not seen in the spectrum analysis. Its not just rumble and noise way down there. I'll have to record the full waveform of an electric bass for you, then I could show you what the attack of individual notes contains significant sub 41 Hz content.
So even if your system isn't capable of lower than 40 Hz reproduction, you still need to have the phase integrity of the signal way down past 20 Hz to not destroy the low end attack. Your LF driver and crossover are already imparting phase shift past Fc. I can guarantee you there will be noticeable degradation in LF quality (including attack and slam, etc) if you further HP the signal. It will be noticeable, even on an open baffle setup or other fullrange dipoles. Even though the spectrum analysis you show doesn't indicate content past 41 Hz for a double bass or lower than that for kick drums, the attack of the waveform still has much lower infrasonic content not seen in the spectrum analysis. Its not just rumble and noise way down there. I'll have to record the full waveform of an electric bass for you, then I could show you what the attack of individual notes contains significant sub 41 Hz content.
Group delay and phase of ideal point source with 40Hz high pass filter with various slopes, just for reference.
Can Money For Nothing track starting part drumming does it have all the bass parts of slam chest punch etc etc. I am not technical but I want to hear this track the best way possible in OB at home, not Mid High OB and a Sealed SUB everything should be OB. what drivers will I need.My CAr Audio installer has given me superb sound in CAr and I love my music in CAr. When I come home I want that sound. Even if I hear that pressure for 5 mins I am recharged. If I dont get get in OB then I will have to get Peerless STW 350 sealed Subs pair60 ltr each box and make a 2 way Purifi BookShelf.
Well, that is a really really helpful specification - not very common on this forum.
Since car audio (it seems to me as an outside observer) consists of monumental boom at 80 Hz and nothing much lower and kind of hit-or-miss treble, it should be easy for others on this forum to suggest how to get there at home.
BTW, while it is simple as could be to make your bass boom at 80 Hz with a small box (like in your car?), unlikely that OB will be a possible approach.
B.
Martian King who has done a lot of work with open baffles recomends using a
program names something like Bassieta , sorry I can't recall the exact name . But
it plots the response of the driver on an OB and even allows for where you place
the driver on the OB. Here is some of his work. http://www.quarter-wave.com/OBs/OB_Theory.html
program names something like Bassieta , sorry I can't recall the exact name . But
it plots the response of the driver on an OB and even allows for where you place
the driver on the OB. Here is some of his work. http://www.quarter-wave.com/OBs/OB_Theory.html
Very interesting discussion. My experience has been that OB gives a much more realistic result for acoustic bass instruments and percussion such as tympani yet for the pipe organ (my hero) some pressure effect is needed to fully capture sustained pedal tones. The difficulty is that the range of frequencies involved overlaps somewhat.
It almost seems like you need the OB woofer and sealed woofer to overlap in the 40-90Hz range. The thing is that would seem to be a tricky thing to do especially in a passive main speaker design. The slope of the passive crossover on the sealed woofer would have to be very carefully designed to integrate the two.
It almost seems like you need the OB woofer and sealed woofer to overlap in the 40-90Hz range. The thing is that would seem to be a tricky thing to do especially in a passive main speaker design. The slope of the passive crossover on the sealed woofer would have to be very carefully designed to integrate the two.
As an aside, listening to any system at a level such that one can 'feel' the bass for any length of time is guaranteed to cause hearing loss. Listening to just one track per day - three minutes exposure - at 110db (not an unreasonable level to actually feel the bass) exceeds the maximum daily dose allowed in industry and would require hearing protection. The OP needs to ask himself if he is comfortable with the idea of wearing bilateral hearing aids in his forties... If he insists on building such a system, I concur completely with others' suggestions of sealed subs.
One of my pet test tracks is The Boy in the Bubble by Paul Simon. A pair of B&C 18PZB100 drivers in 55l sealed enclosures actually shook dust from the rafters in the 1000 square foot vaulted upper floor of my warehouse driven by my paltry Behringer NU3000 testing amp. A setup like this will definitely produce the sound you want.