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sub to the front or rear
What are the advantages / disadvantages to facing an under-strut sub to the front or the rear?
Thanks |
the longer the wave of bass has to develope to greater the end result
facing back is going to yeild louder, deeper bass facing woofers foward toward windsheild will give more punchie result |
As a newcomer here on my350z.com's audio forums, I really hate to disagree with one of the forum's regular contributor's opinions, but I would answer your question *quite* differently. I hope everyone can take my opinions in the spirit they're offered as I am certainly not trolling or attempting to start a flame war.
In my opinion the only true advantage/disadvantage to forward or rear facing subwoofers, in general terms, is for aesthetics and mounting options. In other words, how it's going to look and how you're going to build your box. Here's why I state that and, again, please note, I'm only quoting his post for reference. I am not trying to "call out" anyone. Here's where our opinions differ: the longer the wave of bass has to develope to greater the end result A bass note at: 80hz - Wavelength: 14.125 feet A bass note at: 50hz - Wavelength: 22.600 feet A bass note at: 20hz - Wavelength: 56.500 feet The signifigance of those numbers? Well, they explain two properties of subbass frequencies in general audio environments, and mobile audio in particular. Why subbass frequencies are really not "directional" in the car audio environment and, more importantly for the OP's question, whether one of forward or rear facing driver setups are superior to the other. Take a look back at those numbers, as you can see, none of those distances are available in the interior of most mobile audio environments. As a result, when your subwoofer plays a note at those frequencies the end result is it's basically "pressurizing" the air inside the car. Oh don't worry, I can hear some of the car audio guys screaming already, "but but but... you're wrong dude. Pointing the subs to the rear will effectively "corner load" them from the rear hatch area and they'll be louder!" I mean, heck... facing back is going to yeild louder, deeper bass facing woofers foward toward windsheild will give more punchie result I would simply offer the opinon that you're much better off, to the extent possible, by designing your system where the sound qualities of punchy, loud, tight, etc are being governed by the physical characteristics of the amplifier, such as power levels, the amplifier damping factor, characteristics of the sub driver you choose and the manner in which your box design and construction color the sound. And, while I would tend to concede that a subwoofer may be a bit louder when it's corner loaded, I would argue that this is really only truly generally applicable in home audio. Here's why. In my livingroom I can easily exceed some of the distances quoted above for one full wave at certain frequencies so corner loading the enclosure and giving it those reflective surfaces to fire off can make it a bit louder, though personally I don't care for the "boominess" corner loading can induce. But that's in a livingroom and it's a different thread, besides, my main contention why corner loading really isn't generally applicable here in the car audio environment is simply because it's usually trumped bigtime by a little thing known as "cabin gain". You want "loud" bass? Corner, no corner, front facing, rear facing drivers the car is the perfect enviroment. Why? Cabin Gain. Cabin Gain occurs below the frequency at which a single half wave can no longer occur in the cabin. For example, if the longest measurable distance within the car is 10 ft, then anything below about 60 Hz will have a gain. Obviously the amount of measured cabin gain will vary based on the interior size of the car in question, but it's there, always there. I'm going to cut this reply off now because I'm getting wordy and I could go on. And on. And on. LOL My simple point is that someone's going to have to work really, REALLY hard to prove to me that in these cars forward or rear facing drivers make a difference that can be heard by the average listener, such as the OP, at all. I just know better through both extensive research in the subject matter and the hands-on experience of applying that knowledge over the last 20 years. I'll condense all this down for you to a couple of simple rules. If it's a sealed box, build it how it'll fit and you'll like the look and you'll be happy. If it's a ported box, go ahead and point it to the back to eliminate the possibility of hearing port noise which might otherwise bother you. Outside of that, don't sweat it. Just my $0.02 worth. Regards, ClarkEMTP |
Your overall concept is great clark. The only exception I hvae to bring up is the limited space within a vehicle. With the limited amount of space angles become a HUGE factor in sound. IMO a rear facing sub would give you a better sound (not loudness) gain as facing them towards you would give you a direct path for the waves making it sound somewhat "sloppy". In a Z the rear facing design creates an enclosure in it self to a certain extent with the only path for the air to flow would be above the strut bar between the glass. This would give an amplification effect the average person hears.
The lower frequencies of a sub are much different than the frequencies put out by a mid and high driver. The mids and highs are much better when directed towards the driver while lower frequencies aren't. Lower frequencies when facing directly at the person listening become distorted as they are much wider in wave length. This is different from "port noise" but can sound very similar when larger subs and lower frequencies are emitted. This varies from vehicle to vehicle. IMO the Z just loves the subs facing away from the driver. |
Good response Clark!
You're simply just moving air, add more cone surface area if it's more sub bass you desire... I would focus more on dampening and installation in order to minimize localizing the sub. This is a bit harder to do in a basic install and have only perfected the process by mounting the sub in the dash, under the front seats or engine compartment to eliminate this - not the most practical thing to do in most cases but offers the best results... Sound is so subjective and unfortunetly we live in a headphone generation - the majority of people like what they know and don't know what they like... I've had some pretty funny experiences with novices listening to my car and commenting that the sound is coming from in front of the car and it should be coming from the back... :confused: I just ask them when was the last concert they went to where the sound stage and band was position behind them... :icon38: |
Originally Posted by Philthy
Good response Clark!
You're simply just moving air, add more cone surface area if it's more sub bass you desire... and if you are having issues with "localizing" the sub (im guessing you mean being able to point out where the sub location is), then your crossovers are too high. sub-bass, by definition, is roughly 63Hz and down. 63Hz is the standard benchmark for where frequencies become omni directional, and thus you cant identify a location :) but i whole agree that foward firing vs rear firing is not going to make a difference in our cars. firing upwards might, but not forward vs rear. this is definitly not giong to make any difference in sq or output in our cars. |
Originally Posted by Philthy
the majority of people like what they know and don't know what they like
I have tuned many systems (back in the day) using an RTA, and a couple customers used to tell me it sounded like crap, then they changed the EQ settings to the classic "smile" that eveyone seems to think is the way sound is meant to be heard. Anyway, on topic. I will agree that there is no straight forward "right way" when discussing front or rear firing subs. It is VERY car specific. just like setting up a home theater room. You have to play with placement. The only difference is in the car you are way more limited in your playing. In a trunk, it makes almost no difference front or rear (corner loading can make a slight difference though). In a hatch is a whole different story. Because the wave lengths are so long in the nether regions of bass, you "can" run into cancellation between what's coming from the sub behind you and what is reflected off the windshield. Take the 80Hz at ~14' for example. If the sub was front-firing, measure the distance from the subwoofer to the windshield, then from the windshield to the driver's head. If it is 14' then there will be some cancellation around 80Hz and you will notice a bit of dropout in that frequency. Now turn that sub to a rear firing setup and measure.....it will be more like 20'....which will cause cancellation around 50Hz. The human ear will notice the missing 80Hz more than it will the missing 50Hz, so the rear firing setup will just sound better. So until automakers can invent sound-absorbent glass instead of sound-reflective glass, there is a difference but it is vehicle specific. ***The numbers above are for illustration purposes only and are not actual measurements*** |
speaking not in theory but in experience with these 350z
i have done woofer back port back woofer up port up woofer up port to driver side woofer up port to passenger side woofer back port to passenger side loudest on the meter woofer up port back best sounding woofer back port back i have done no woofer aimed forward cause i would only do that in a wall |
Originally Posted by hoss4131
not neccisarily true... more output can be achieved solely through the install, or also by using a woofer with a higher xmax or higher efficiency rating.
and if you are having issues with "localizing" the sub (im guessing you mean being able to point out where the sub location is), then your crossovers are too high. sub-bass, by definition, is roughly 63Hz and down. 63Hz is the standard benchmark for where frequencies become omni directional, and thus you cant identify a location :) Higher xmax = moving more air ;) higher efficiency = less wattage required... You CAN localize freq below 63Hz in a car- I'll give you a good exersize that will immediately reveal localization - get a hold of 'The Planet Krypton' by Erich Kunzel and the Cincinnati Pop, there's an organ pedal tone at about 18Hz, 1:09 into the track and a great example of what I mean by localizing the sub... You can post data that support path lengths at freq below 100Hz, and sub is omni directional, etc, etc... but it's the vibration and resonance that comes from the areas around the sub enclosure that cause localization. Ideally, having a car that is vibration free would negate this effect and there is just ONE car in my 20 plus years of top level competition that was able to execute solid upfront bass (Mark Eldridge 4-Runner) and the measures that he went through to accomplish this task were endless - Mark is now utlizing subs mounted up front in his new comp car, go figure because it works best! The 'realness' of subs upfront is hard to put into words and must be experienced. There's nothing like the impact of a kick drum coming from upfront subs - that sound should have some weight to it and it does with up front subs. Next time you go to a play, concert or any other live performance event, try sitting in the front row or really close to the stage - you'll experience what I mean when I say tacticle effect, you really FEEL the music, not just hear it... |
I experimented with the sealed sidebox I had in my Z. I started with it facing the side. Moved it facing up, backward and forward.
The differences between each position were very slight. The front facing position provided the most "accurate" sound. And back, up and side provided more of a "boom" or muffled type of sound. |
Originally Posted by Driven1
Your overall concept is great clark.
With the limited amount of space angles become a HUGE factor in sound. IMO a rear facing sub would give you a better sound (not loudness) gain as facing them towards you would give you a direct path for the waves making it sound somewhat "sloppy". In a Z the rear facing design creates an enclosure in it self to a certain extent with the only path for the air to flow would be above the strut bar between the glass. This would give an amplification effect the average person hears. IMO a rear facing sub would give you a better sound (not loudness) Sorry, I'm really NOT picking on you. I just use this as an example to illustrate what I said because it immediately jumped out at me. That's why I try to leave out my opinions and provide the facts of what happens and why. I'll let the person asking the question decide for themself what sounds good. That way, not only will they know what they like when they hear it, but hopefully they'll understand a little of why it sounds the way it does. Maybe knowing just a little will shorten the long and winding path to get there for them. lol The lower frequencies of a sub are much different than the frequencies put out by a mid and high driver. The mids and highs are much better when directed towards the driver while lower frequencies aren't. Lower frequencies when facing directly at the person listening become distorted as they are much wider in wave length. Regards, ClarkEMTP PS - Richard Clark is one of my hero's. No, we're not related. lol |
Originally Posted by clarkemtp
PS - Richard Clark is one of my hero's. No, we're not related. lol
|
Originally Posted by Philthy
There's a name from the past :icon38: The last time I hung out with Richard he was playing around with his five foot subwoofer in the bread box truck! I should give him a call and catch up with him...
hahaha I wondered if I was the only "old fart" around here old enough to actually know who Richard Clark was/is? lol :icon44: |
Originally Posted by clarkemtp
I wondered if I was the only "old fart" around here old enough to actually know who Richard Clark was/is? lol :icon44:
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Originally Posted by StreetOC192
Nahhh, there's a few of us older dudes around, LOL
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forward!
|
Originally Posted by clarkemtp
As a newcomer here on my350z.com's audio forums, I really hate to disagree with one of the forum's regular contributor's opinions, but I would answer your question *quite* differently. I hope everyone can take my opinions in the spirit they're offered as I am certainly not trolling or attempting to start a flame war.
In my opinion the only true advantage/disadvantage to forward or rear facing subwoofers, in general terms, is for aesthetics and mounting options. In other words, how it's going to look and how you're going to build your box. Here's why I state that and, again, please note, I'm only quoting his post for reference. I am not trying to "call out" anyone. Here's where our opinions differ: Sound, like ripples on a pond, radiates from it's source in waves. The length of these waves vary with the frequency. The lower the frequency, the longer the physical length of the wave. Picture the tiny interior of these cars, now think about the following: A bass note at: 80hz - Wavelength: 14.125 feet A bass note at: 50hz - Wavelength: 22.600 feet A bass note at: 20hz - Wavelength: 56.500 feet The signifigance of those numbers? Well, they explain two properties of subbass frequencies in general audio environments, and mobile audio in particular. Why subbass frequencies are really not "directional" in the car audio environment and, more importantly for the OP's question, whether one of forward or rear facing driver setups are superior to the other. Take a look back at those numbers, as you can see, none of those distances are available in the interior of most mobile audio environments. As a result, when your subwoofer plays a note at those frequencies the end result is it's basically "pressurizing" the air inside the car. Oh don't worry, I can hear some of the car audio guys screaming already, "but but but... you're wrong dude. Pointing the subs to the rear will effectively "corner load" them from the rear hatch area and they'll be louder!" I mean, heck... ...that's the basic result of "corner loading" in a nutshell right there. I would simply offer the opinon that you're much better off, to the extent possible, by designing your system where the sound qualities of punchy, loud, tight, etc are being governed by the physical characteristics of the amplifier, such as power levels, the amplifier damping factor, characteristics of the sub driver you choose and the manner in which your box design and construction color the sound. And, while I would tend to concede that a subwoofer may be a bit louder when it's corner loaded, I would argue that this is really only truly generally applicable in home audio. Here's why. In my livingroom I can easily exceed some of the distances quoted above for one full wave at certain frequencies so corner loading the enclosure and giving it those reflective surfaces to fire off can make it a bit louder, though personally I don't care for the "boominess" corner loading can induce. But that's in a livingroom and it's a different thread, besides, my main contention why corner loading really isn't generally applicable here in the car audio environment is simply because it's usually trumped bigtime by a little thing known as "cabin gain". You want "loud" bass? Corner, no corner, front facing, rear facing drivers the car is the perfect enviroment. Why? Cabin Gain. Cabin Gain occurs below the frequency at which a single half wave can no longer occur in the cabin. For example, if the longest measurable distance within the car is 10 ft, then anything below about 60 Hz will have a gain. Obviously the amount of measured cabin gain will vary based on the interior size of the car in question, but it's there, always there. I'm going to cut this reply off now because I'm getting wordy and I could go on. And on. And on. LOL My simple point is that someone's going to have to work really, REALLY hard to prove to me that in these cars forward or rear facing drivers make a difference that can be heard by the average listener, such as the OP, at all. I just know better through both extensive research in the subject matter and the hands-on experience of applying that knowledge over the last 20 years. I'll condense all this down for you to a couple of simple rules. If it's a sealed box, build it how it'll fit and you'll like the look and you'll be happy. If it's a ported box, go ahead and point it to the back to eliminate the possibility of hearing port noise which might otherwise bother you. Outside of that, don't sweat it. Just my $0.02 worth. Regards, ClarkEMTP |
Originally Posted by clarkemtp
Tisk tisk tisk. Shame on you. "Name dropping" is sooooo ugly. LOL LOL LOL :p
hahaha I wondered if I was the only "old fart" around here old enough to actually know who Richard Clark was/is? lol :icon44: Reading some of these threads reminds me of the write in q/a that Car Audio used to publish in their mag - too funny... |
theory can be argued all day
until you try every position ,on a meter, than that will tell you what is the loudest , that is cut and dry as far as what sounds better it may sound better foward to some and backward to others, and up to others no right or wrong just subjective taste |
Originally Posted by 350zspl
theory can be argued all day
until you try every position ,on a meter, than that will tell you what is the loudest , that is cut and dry as far as what sounds better it may sound better foward to some and backward to others, and up to others no right or wrong just subjective taste |
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