subwoofer questions.
#31
RE: subwoofer questions.
ORIGINAL: falkore24
Resonant frequency is when a wave (sound, tide, engine RPM, etc.) is reflected within the object and crosses the following wave in phase so that they build on each other for a split second. Now, consider this happening at the speed of sound. The built waves split apart, but are reflected back again. Now they cross a third freshly generated wave, all in phase ..... so the wave amplitude is trippled ...... depending on the resonant frequency, mass of the system, type of wave generated and decay rate of these waves, this resonance can become several thousand times as strong as the original wave.
Resonant frequency is when a wave (sound, tide, engine RPM, etc.) is reflected within the object and crosses the following wave in phase so that they build on each other for a split second. Now, consider this happening at the speed of sound. The built waves split apart, but are reflected back again. Now they cross a third freshly generated wave, all in phase ..... so the wave amplitude is trippled ...... depending on the resonant frequency, mass of the system, type of wave generated and decay rate of these waves, this resonance can become several thousand times as strong as the original wave.
#32
RE: subwoofer questions.
Dampening and changing the resonate frequency if it's going to be seeing frequencies close to it's resonance I guess. I don't know what you would do in when engineering a structure, but when building a subwoofer box you add mass by using thicker MDF to bring the resonance frequency down, or you reduce the mass and make it stiffer to raise it.
#33
RE: subwoofer questions.
Good to know. I shouldve clarified, how do they make sure you wont hit the resonance frequency in things like a jet engine, etc. I mean, you made it out to seem like its a common thing. Or, are some of these frequencies just so high/low that its not realistic that they would ever create them within normal operating conditions?
The way I understood resonance from chemistry was the frequency of energy needed to destroy the bonds between atoms withing an element or molecule. Say, water and microwaves, for example. Your typical microwave vibrates the water molecules and increases the energy (heat) of the food. Meh, I was going to continue on this... but Im not sure if Im wrong or right and have a headache... lol
The way I understood resonance from chemistry was the frequency of energy needed to destroy the bonds between atoms withing an element or molecule. Say, water and microwaves, for example. Your typical microwave vibrates the water molecules and increases the energy (heat) of the food. Meh, I was going to continue on this... but Im not sure if Im wrong or right and have a headache... lol
#34
RE: subwoofer questions.
Well with a jet, they know about what range of frequencies the turbines and fans putout and anythign else that may produce vibrations and make sure the resonance of the structure is outside of that range. I don't even have my AA yet and I never learned this in school so forgive me if I'm a bit off, everything I know was self taught so it's not always the best answer.
#35
RE: subwoofer questions.
Jet engines have passive baffles in the various chambers to alter and help prevent resonance. Also, the throttle controls are set up to blip over the position that causes the resonance. For example, if 40% throttle caused the problem, the computer control wil let it go 37, 38,42, 43% ..... or something to that effect. I'll PM you a research project that I was involved in that is way too much to post here.
#37
RE: subwoofer questions.
Very interesting read, I've only just read a bit but it seems most to come is going to be a bit over my head. My brother in laws brother is finishing up his PHD in thermal engineering at UofM, and he's been working with some company doing R&D on turbines, every time he comes over he's always got some really interesting facts on turbines and stuff.
#38
RE: subwoofer questions.
ORIGINAL: finch13
I think you could fit 87 pages in here....
I think you could fit 87 pages in here....
#39
RE: subwoofer questions.
Polk Audio makes a really nice 12 inch sub. In something as small as an accord I would go with a good sealed box. Ported works alot better for vehicles with lots of space, for instance, I have 3 10's ported in an suv. And I'm from bama so I know the low frequency bass lines. I think some Polks would sound good with some Jeezy goin through 'em. I haven't done anything with my audio system yet, but I'm probably gonna go with Polk if not JBL.
#40
RE: subwoofer questions.
I've never heard a polk sub, but JBL isn't all that at all. Their home audio stuff ins't bad, I have nice outdoor 3-way JBLs on my balcony that I really like. But their subs haven't been top notch for many years. Also I'm pretty sure the polk subs are SQs and not SPL which you are making them sound like.