SPL - importance of what's going on inside the box vs. outside
your choice in vehicle can have a big impact on performance but once that vehicle of choice is made, there are only certain thing you can do to maximize its efficiency...you then must rely on equipment and enclosure which possibilities are nearly endless.
for example, in street you maximize performance from lower input power by use of a smaller box that can make woofers reach peak compression on say 3kw per woofer, in SS you would try to make the woofers peak on about 20-30kw each so a larger box+port combo is needed. obviously this is only a partial story but the bottom line is that with different variations of equipment+enclosure you can make the same car play on different levels...hence why we have classes like ST, st.MAX, no-wall and SS.
The only classes where the car is everything is extreme..if the basic shape of the exterior is cloe to square and the front cabin is short from b-pillar to a-pillar than a properly tuned BP can be achieved using the entire vehicle, the equipment used must only be strong enough to withstand the pressure it creates and only enough power is needed to peak compression "any more on each woofer should only break it"
for example, in street you maximize performance from lower input power by use of a smaller box that can make woofers reach peak compression on say 3kw per woofer, in SS you would try to make the woofers peak on about 20-30kw each so a larger box+port combo is needed. obviously this is only a partial story but the bottom line is that with different variations of equipment+enclosure you can make the same car play on different levels...hence why we have classes like ST, st.MAX, no-wall and SS.
The only classes where the car is everything is extreme..if the basic shape of the exterior is cloe to square and the front cabin is short from b-pillar to a-pillar than a properly tuned BP can be achieved using the entire vehicle, the equipment used must only be strong enough to withstand the pressure it creates and only enough power is needed to peak compression "any more on each woofer should only break it"
check out the JL audio web site... back in the day they had a nice tutorial on enclosure design... not sure if they still have it....
if you are into reading books... back in the day there was a nice book called the speaker box cookbook or something like that... but you shouldnt have too hard of a time finding online material either...
just try google with something like how to design a subwoofer enclosure
looks like they dont have it anymore
ok lets see this eems to be pretty good... sorry im just quickly skimming though
http://www.danmarx.org/audioinnovation/theories.html
if you are into reading books... back in the day there was a nice book called the speaker box cookbook or something like that... but you shouldnt have too hard of a time finding online material either...
just try google with something like how to design a subwoofer enclosure
looks like they dont have it anymore
ok lets see this eems to be pretty good... sorry im just quickly skimming though
http://www.danmarx.org/audioinnovation/theories.html
Last edited by MTA; Sep 3, 2010 at 07:17 PM.
0 Watt CAFz'r
Joined: Oct 2009
Posts: 42
I would like to start off by saying I have learned alot through this forum, you guys are very informative and helpful (when you are in the mood).
Based on my experience within the past 2 1/2 yrs, I do agree its all in the enclosure. But I have also learned that there is a certain relation with the Cabin/Enclosure (size). Meaning that depending on the size of the cabin you can't put to big of an enclosure into it.
Now speaking of Matting, I do disagree in matting first and building box next. All cars will have areas they need to flex in especially for Street, and matting those areas can actually hurt more than gain.
Now when it comes to enclosures thats the fun part, there are many options to go with. But its all about testing with what your vehicle likes best, since enclosure designs are infinite, but you only have one cabin!
Based on my experience within the past 2 1/2 yrs, I do agree its all in the enclosure. But I have also learned that there is a certain relation with the Cabin/Enclosure (size). Meaning that depending on the size of the cabin you can't put to big of an enclosure into it.
Now speaking of Matting, I do disagree in matting first and building box next. All cars will have areas they need to flex in especially for Street, and matting those areas can actually hurt more than gain.
Now when it comes to enclosures thats the fun part, there are many options to go with. But its all about testing with what your vehicle likes best, since enclosure designs are infinite, but you only have one cabin!
1000 Watt CAFz'r
Joined: Jan 2005
Posts: 1,149
I have to disagree, cabin size and enclosure size have nothing to do with each other. Enclosure size determines how efficiently a woofer plays at a certain position in the cabin.
Generally;
the smaller the enclosure, the higher the impedance rise.
the smaller the enclosure, the higher frequency it will peak at.
the bigger the enclosure, the lower frequency it will play in the same area
That's what happens when more woofers and bigger boxes are in crx's, they start to play lower frequencies and the total impedance stays the same because more coils are added.
so therefor there is a relationship between the enclosure size and frequency of the cabin not size.
Generally;
the smaller the enclosure, the higher the impedance rise.
the smaller the enclosure, the higher frequency it will peak at.
the bigger the enclosure, the lower frequency it will play in the same area
That's what happens when more woofers and bigger boxes are in crx's, they start to play lower frequencies and the total impedance stays the same because more coils are added.
so therefor there is a relationship between the enclosure size and frequency of the cabin not size.
0 Watt CAFz'r
Joined: Oct 2009
Posts: 42
I beg to differ, you are completely demonstrating that cabin does have an effect on your enclosure. You stated;
the bigger the enclosure, the lower frequency it will play in the same area
therefore by reducing your cabin size, you are affecting your cabins RF, also by lowering your RF or as you stated (lower the freq. it will play in the same area), you will be lowering your DBs, due to the lower hz you will be burping at. These are the same exact responses I have seen the ones you have stated, by which are the same responses on which I am basing my statement, I dont intend to offend or contradict what you are saying. I do believe we are on the same understanding just have different views of the results.
And on your comment of the bigger boxes in CRx, yes its true they do peak at lower frequencies, but consequently will lower their SPL score due to the same effect of a lower peak HZ.
That is therefore a cause and effect upon size of enclosure in relation to its cabin area, a cabin will only allow a certain size before it starts to decline in score.
the bigger the enclosure, the lower frequency it will play in the same area
therefore by reducing your cabin size, you are affecting your cabins RF, also by lowering your RF or as you stated (lower the freq. it will play in the same area), you will be lowering your DBs, due to the lower hz you will be burping at. These are the same exact responses I have seen the ones you have stated, by which are the same responses on which I am basing my statement, I dont intend to offend or contradict what you are saying. I do believe we are on the same understanding just have different views of the results.
And on your comment of the bigger boxes in CRx, yes its true they do peak at lower frequencies, but consequently will lower their SPL score due to the same effect of a lower peak HZ.
That is therefore a cause and effect upon size of enclosure in relation to its cabin area, a cabin will only allow a certain size before it starts to decline in score.
