How do I get my system louder?
Posted on 27. Jul, 2009 by Jefferson Bryant in Industry News
One of the greatest tools in the audiophile toolbox is math. What? Math sucks you say. Well I say get your calculators out and start working your brain. This will be fun, honest.
In retail, chat forums and lunch rooms across the country the single most common questions are “how do I get my system louder” or “how loud will these subs be”. I can personally guarantee you that you ask ten people this question, including the guys at the stereo shop, you will get 13 different answers and none of them will be basing their answers on facts. They simply do not know how it works. There are some basic physics at work here.
Volume, which is measured in decibels (expressed by dB), is a function of power, cone area, enclosure design, and transfer function. Oh, you knew that already? Ok, sure that last statement might seem a little obvious, but undestanding how they interact togethr is critical to calculating volume. That’s right, you can calculate exactly how loud you system will be. Enough BS, here is the worksheet. You won’t find this anywhere else, send your friends.
This formula requires a few specs. First, you need the sensitivity of the sub(s). This listed on the woofer spec sheet in dB. It is sometimes notated as the SPL of the sub. Next, you need to know how much power your amp puts out. An amp birth-sheet (usually included in the box) will have the actual power the amp displayed when it was tested at the factory. Not all amps come with these. If you do not have such a sheet, you can use the power ratings, or even better, you can test it yourself (that is whole other enchilada and we will get into that another time). Other specs you need are more simple- what type of car do you have- truck, hatchback, or sedan; and what kind of box is it installed in. The enclosure will make a big difference, if it is a crappy home-built box with lots of leaks, held together with carpet and liquid nails, it probably won’t function as well as a professionally-built enclosure (like the Q-Logic pre-fab enclosures- shameless plug) and how many woofers you have. Have fun.
Sensitivity =
Every time the cone area doubles, the output of the system increases by 3 dB, which is relative to a doubling of volume. If you have 4 subs, you would add 9 dB to the sensitivity rating of the subwoofers.
add 3 dB per doubling of cone area
i.e. 2 subs, 3 dB, 4 subs, 6 dB
Let’s consider sub sensitivity, with 3 dB per sub added and calculate the SPL. Each time the output power (wattage) of the amplifier doubles, the SPL increases by 3 dB. To figure this, use the following figures.
This represent 3 dB added per doubling of power starting at 1 watt/meter SPL.
1=0
2=3
4=6
8=9
16=12
32=15
64=18
128=21
256=24
512=27
1024=30
2048=33
4096=36
8192=39
Next we add in Transfer Function
add 12 dB for a standard car/truck
add 16 dB for a hatchback car
Now we figure in box type
For a sealed box, 0 dB, sealed offers no dB gain.
For a ported box, 3-9 dB depending on tuning frequency and air ripple. The higher the ripple, the more gain but at a cost of sound quality.
For a bandpass box, 6-12 dB again depending on the tune freq. and ripple.
For example, a 12″ Rockford Fosgate subwoofer has a sensitivity of 86 db at 1 watt/1 meter, and is capable of handling 300 watts.The sub is installed in a ported enclosure, so we are going to use a the lower output rate for the ported box at 3 dB. Powering the subwoofer is a Rockford Fosgate Punch 300-1, which is rated at 300 watts to a single 4-ohm load. All of this is installed in a 2006 Honda Civic Si, which is a hatchback and gets a boost from the 16 dB transfer function. Using the formula, we get the following results-
86+ 24 (at 256 watts, it is close, but you could add in an extra dB if you want) + 16 (trans function) + 3 (box gain) = 129 dB estimated output. This estimation will be within +\- 3 dB of the measured output. This is simple physics, and it works.
norman
13. Sep, 2009
hello I have a single 12″ bandpass box with a alpine swe-1242 sub.is this encloser good for my sub.my amp is a profile california ca 400m
JeffersonBryant
13. Sep, 2009
The Alpine SW-1242 is a great subwoofer. While the typical enclosure for this sub is a type 1 or 2, a bandpass enclosure will get you the most boom for your money. If you just want big boom and don’t really care about tonal accuracy or muscality, then it will get you there. The 1242 is not designed for a ported enclosure, so you are limited to a sealed enclosure or bandpass for that one. While you will lose some bass (to the tune of about 6 db), the Alpine subwoofer is more of a sound quality sub versus SPL, and a sealed enclosure will sound better. Good Luck with your system. Send us a pic and we will put it up with you comments.
Curtis
19. Oct, 2009
hi…
Im starting my first system and i do want some spl in there but i dont have enough money for 18s or 22s, so (to some people this might be sad but i got 2 12s from wallmart and a 200 watt peak 85 watts rms amp. the subs are VR3 VSW120, 400 watts peak and 50 watts rms. they recommend a seald enclosure but i want to try ported with them but i fiqured i would ask someone about enclosure types and tuneing freq.s. i have a 95 jeep grand cherokee if that helps any. also i have designed and built some ported enclosures for 8s and they turned out pretty good. i use 3/4 inch MDF seald with wood glue, culking and screws, L port instead of round or tube.
thanks….
JeffersonBryant
21. Oct, 2009
Curtis,
Hey, we all have to start somewhere! My first system consisted of a set of Pioneer 10″ subs from Sears, a pioneer tape deck and a Jensen amp, so I am right there with ya. As far your subwoofers, the only info I could find was basic installation directions, there were no specs. Without specs, it would be hard to build the perfect box, but I would suggest a ported enclosure. The nice thing about a ported enclosure is that it can be tuned to match the subwoofer, so once you upgrade to better subs, you can keep the same enclosure, as long as they are same size.
barry
15. Nov, 2009
Hi Jefferson,
I am getting two Kenwood KFC-W3012 subwoofers and Kenwood KAC-8104D 100 w amp. I am considering Scosche SEV122 ported dual or Atrend E12Dsv B Box Series 12-Inch Dual Vented Enclosure with Shared Chamber and even a simple Atrend E12D B Box Series 12-Inch Dual Sealed Bass Boxes. What would you do? I am a newbe.
Thank.
Barry
Jefferson Bryant
16. Nov, 2009
Barry,
I am a big fan of Kenwood gear, I used to compete in DB Drags with Kenwood back in the day. The 3012 is good sub, and with a dB rating of 86, with two subs and a ported box you will be looking at about 134 dB with that amplifier in a typical car or truck, if you have a hatchback, it will be even louder. 134 is dang loud. While the Atrend looks good, I can’t find any specs on the volume. That is a key part of the equation. Personally, I would go for an enclosure that you knew had the right internal volume, like the Q-logic dual 12″ Type 2 vented enclosure. This enclosure is spec’d at 1.5 cu ft per sub, which is the recommended vented spec for those subs. It would sound really good. If you want volume, go for the ported enclosure. I rarely run a sealed enclosure unless I either have no room for the added airspace OR it is for an SQ only system (even then I can still get loud). But I like the big boom, and its your call. Either way, have fun with it. Good Luck!
Brandon
17. Nov, 2009
Jefferson,
With a rockford P1000-1bd amp and two rockford P3D212 subs, what am i looking at for dB’s? And whats your recomendation on a box? I’m looking at getting a different box and would like a direction to look.
thanks brandon
andre
19. Nov, 2009
hey jefferson i stumble on this sight cause im building a spl system for my 1997 suburban i have 3 xplod 1300 w subs now with a 1600 power acoustic amp but im ready to but some 18″s i dont know if i should go with the four or two im not worried about the trunk space now since i have three rows of seats (just relize that.) but i seen this 01 tahoe on the net and im hooked could u give me some pointers oh yeah im upgrading everything amps,alts,battery cells and all well thanks looking forward to see what help u got if any thankx dre from south jersey!
Glen
01. Dec, 2009
Hello Jefferson
I am hopefully starting my first system in my 1994 S10 Blazer. I am looking at the Alpine type R 10′ sub model # SWR-1022D powered with the Alpine Mono block amp # MRP-M500. I was looking at your enclosures and wondering which should I go with. I noticed the Q Logic Type 2 QLH-10S110SV has a volume of 1.10 cu ft. the subwoofer specs call for a .5-.8 cu ft ported box. Would this box work? some people told me of the volume that the actual sub will take up. Is that important. I also noticed the type 4 enclosure QB-110.3 with a .58 cu ft volume, would that enclosure be large enough? I just don’t really know which enclosure would work properly. Any help would be greatly appreciated.
Thank you
Glen
Glen
02. Dec, 2009
Hello Jefferson
I will be setting up my first audio system with a sub in my 1994 S10 4D Blazer. I am going with the Alpine 10″ 2 OHM Type R subwoofer, Model # SWR-1022D. I will be using the Alpine Mono Amp, Model # MRP-M500. I was on the Q Logic site and saw two enclosures I am interested in. One is the type 4 QB-110.3 and the type 2 QLH-10S110SV. Which enclosure would you suggest. and is my calculated 128dB rating somewhat accurate? The suggested enclosure volume for a vented box is .5-.8 cu ft. is the type 2 box too large at 1.1 cu ft? is the type 4 too small at .58 cu ft? I have heard you must accomadate for the volume that the sub takes up. Is that true?
Thanks
Glen
steven
11. Dec, 2009
i have two power acoustik mofo 12s with a stax 5500 d mono amplifier in a seal enclosure how many db should i be hitting?
Miguel
08. Jan, 2010
Hi jefferson
I have a 2003 F150 extended cab. i have all kicker audio. I lifted my back seat 4″ and i have 2 12″ kicker cvr subs 2ohm each. and powering them is a kicker zx750.1 i have 61/2 kicker components in the front and kicker 6×9′s in the back powering them is a kicker zx350.4. my problem is i have each sub in there seperate box a cubic foot each and they sound alright but i want the bass to hit harder. i was thinking of rebuilding my box and taking the amp out from the middle of the two boxes and making the box just one as long as the back seat and just dividing it in the middle of the box. i wanted some experties from you. will this help my subs hit the lows better and i hear boxes in trucks sound better upside down? Or do you suggest some diffrent subs? i willing to try new stuff. thanks!
tim
13. Feb, 2010
i am getting 2 phoenix gold rsd 124 12″ competition subs and running them off a lanzar vibe 286 4000 watt 2 channel amp in a car with the back seats down so technically a hatchback? what is the decibels that i can achieve the subs are rated at 94db.
Mary
09. Mar, 2010
i have a 97 s10 blazer with 2-15 xs15D with 2-5500 spl gorilla series amps on them. i have three batteries and my alternator has been beefed up. the specs for the enclosure says 4.5cuft per sub. i have a 9.1cuft enclosure that is ported with 4×5″ ports two for each sub. i am at a 148db on the window but i am concerned that the enclosure is what is keeping me from getting the 150db that i am after. any suggestions?
Jason
22. Mar, 2010
Hello, I was wondering if I use a bigger box, will I get more DB for SPL woofers. I have 2 12” Orion HCCA 12.4 woofers. I wanted to fiberglass a box but im not sure if ported out of MDF is better and how big should this be? This will be going into a 05 Durango with 3rd row seat removed I have L 47.5” x H 30” W 22”. These are going to be powered by 2 HC2000 Kenitik batterys on a 250 amp alternater. Amp will be a power accoustic BAMF 5500/1. How would this sound? Thanks for your help.
Rodrigo
20. Apr, 2010
Hi jefferson
i just installed two re se 12″ 600rms watts each dual 4ohm. Im running them with a hifonics 1610d. the box is ported i dnt really know its turning. but i thinks its around 2.0cu ft. each of these subs are rated at 86bd. how many db you think i should be hitting? Thanks.
ethan
09. May, 2010
i have 2 12″ vr3 vsw120 in a ported box and i was wondering what would be the best budget friendly amp to buy.