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View Full Version : p1000 and 12 inch Memphis SPL box?



04tiburongt
01-29-2012, 04:12 AM
I have a 04 Tiburon GT hatch, everything in car is mepmphis, looking to make a SPL box for this Mojo, to be around 44 Hrtz thats what the car is peaking at, but have looked every were trying to find some help with designs and nothing yet, if anyone could help me i would be greatful, using Berch

Moble Enclosurs
01-29-2012, 09:50 AM
If you want to purchase a design, I can help you out. Check out my website for all the details on what I do. Let me know if you would be interested. :D

pro-rabbit
01-29-2012, 10:11 AM
For SPL purposes there is no need for a "design" of sorts. You will build about 10 or more enclosures for every .01 db you want to increase.

I have done the SPL thing many times over, and there is just a simple method behind this. Build...test....rebuild....repeat........repeat... .and then repeat.

There is no way for any designer/builder to design a "perfect" SPL enclosure via the internet. I get asked this all time and it really cracks me up. I will give you my advice on what I think you should do, but in the end it boils down the "method" to get loud.

For instances, if we model the car and it peaks at 40hz or so and we build an enclosure around that it may or may not perform how you want. Sub and port placement as well as enclosure placement play a massive roll in SPL as does the method in which you want to be metered. Since each org has a range of rules for various classes you need to figure out where and what class you want to run in. Then read the rules(very carefully). The next thing is to test sub/port/enclosure placements to see what will net the best result. Then start playing with enclosure size and tuning. Before long you will be a decent number and it will take drastic improvements to increase the score as you will be hitting that threshold of where you can no longer do quick easy things to increase even .1 of a DB.

Moble Enclosurs
01-29-2012, 11:08 AM
For SPL purposes there is no need for a "design" of sorts. You will build about 10 or more enclosures for every .01 db you want to increase.

I have done the SPL thing many times over, and there is just a simple method behind this. Build...test....rebuild....repeat........repeat... .and then repeat.

There is no way for any designer/builder to design a "perfect" SPL enclosure via the internet. I get asked this all time and it really cracks me up. I will give you my advice on what I think you should do, but in the end it boils down the "method" to get loud.

For instances, if we model the car and it peaks at 40hz or so and we build an enclosure around that it may or may not perform how you want. Sub and port placement as well as enclosure placement play a massive roll in SPL as does the method in which you want to be metered. Since each org has a range of rules for various classes you need to figure out where and what class you want to run in. Then read the rules(very carefully). The next thing is to test sub/port/enclosure placements to see what will net the best result. Then start playing with enclosure size and tuning. Before long you will be a decent number and it will take drastic improvements to increase the score as you will be hitting that threshold of where you can no longer do quick easy things to increase even .1 of a DB.

True, only because perfection is still even a variable in the audio world. But a basis of something is ALWAYS the best route to go, or you WILL find yourself going through over 10 enclosures to get there. We also have the ability as a designer to DESIGN a variable tuning port incorporated for those tweaks on the go. Though, the perfect method is ALWAYS testing and getting your OWN numbers, you might as well get a better start than just build and test. The closer you are to your goal, the quicker and more accurate you can find that goal. So, I will have to disagree that using a designer is likely not a smart route to take.

Someone who says that may have no idea of what one designer may be capable of. Sound is not just an art, it is a science. And behind the science lies solutions. And the fact that they are mathematical, then they are absolute in all cases. Its a matter of how many solutions you are willing to go through to get a better average for a single design. Those who do not know anything about transfer function need to stay away from things like this as that is the key to pressure related sound wave reproduction.

Saying that a car peaks is not even accurate. A car does not peak at a single frequency. It has a multiple gain across the spectrum at which there are actually two points within the range we look at in sub-design where a car has the same efficiency increase. And they are no harmonics of each other either, though some can be very close. How many other designers know that? You would be surprised what can be understood about propagation if the study is extensive enough. You will find that yes, perfection is impossible, ESPECIALLY with only mere calculations, but we have come a long way from build and test, build and test. In order to build and test, you still need a base.like anything else. This is the structure of SPL designing, considering there are no general rules that work for every design.......much like designing bandpasses.

I see what you are saying, but I have to believe that what I do does make a difference in this form of audio output as well as any other. I can tell you one very important factor about car functions that many do not realize.......the actual 'peak" that is spoke of is not even a full wave peak. Its not even a half wave peak. Is is not even a quarter-wave peak. It is a function based on a big part of what the enclosures performance is, not the other way around. For instance, if I have a 72Hz resonance node in the vehicle, and my enclosure is based around a 44Hz peak resonance (very popular frequency used as a general resonance for small suvs), then the obvious peak will show on the meter to be around 44Hz. This is where the logarithmic output of the enclosures increase overrides the gain levels of a reference 0dB level and hides the transfer function of the vehicle behind the enclosures peak.
If that same enclosure was "tuned" to around the 72Hz, the SPL levels will be increased quite a bit near that level. I do not know of any vehicle that has lower than a 50Hz resonance without including enclosure factors in figuring for this. This is why some comps allow for up to an 80Hz frequency to be utilized.

Im sure those who know SPL understand some of this, or maybe all of it, idk. But I have to feel that a contribution on the part of a designer is a valuable asset in figuring for SPL figures as long as the designer is knowledgeable in what they are figuring for. Because the designer can give advice on what will work best for the application of the owner's build, and hopefully save time in the process if anything is accomplished as a minimum.

There will always be an underlying conflict between this "designer" and "OJT" type of enclosure construction accuracy, and both parts have their strong points. But, knowing sound in and out is a valuable asset in car audio SPL designing as well as any other audio application. There are quite a few things about sound that many people do not consider. Which is why rebuilds are done so frequently. I, nor any other designer can give perfection. But, ACAP is better than, "lets try 2 cubes on 34Hz and see what it does first". Or "I want to tune low cause its impressive but still be in the 150s" without understanding the limitations involved, not just physically, but acoustically. And I think you can agree that only a true audio designer can get those figures close enough for only tweaks if any.

Every other point made, I agree with. :D

Moble Enclosurs
01-29-2012, 11:14 AM
Keep in mind that what I am saying is not in disagreement, but to portray the importance of design in all aspects of audio. The method you speak of....that cannot be argued. That is not what I wrote about...... just what was in bold. I wanted to clarify that....and that this was not written in argument, but to impose a possible importance of designing even though other methods can be utilized in a final solution.