very interesting.. nice to see another audio buff on here
i have a custom Home audio/Video stereo shop
first off, test out a pair of Martin Logan electrostats (Home audio), that will redefine your ear to a degree that you will die trying to recreate that in your car!!
Im a little baffaled about the center driver you have (did you use that to get the center image), if so Iasca frowns upon that,... did you glass the 8"s ???, and have you had any other sub boxes, seems odd to have the two 12"s in a ported enclosure rammed against the trunk lid ... im sure you did your homework, but for all of my SQ systems i've done, ive always been happy with the smallest sealed box.. of course i usually have to build about 5 of them to get it exactly right ...
overall it seemed really cool, and i would like to hear it since you have alot of non-popular stuff
for some suggestions, have you looked into kicks, you might acheive that magical center image that will blow you away (that why you liked the senhiesers so much, the sound is equivialant at both ears!!) , i would also try moving the tweeters aroundl... the stock location is really bad.. i would just get some 2 sided tape, and stick in different places for a couple of days while you test stuff (one general idea is close to the midrange), i would also try low in the door... the tweeters are the dominant force in a soundstage, they have the ability to pull the sense of direction all over the place.. and lastly i didnt have a chance to read your whole page, but do you have tweeters in the rear.. if so try losing them for a couple of days.. keep the mid, but lose the tweet, you might be surprised
I am actually a loudspeaker designer as that is what I do and have done for a living for the last six years.
The centre speaker is there to recreate a really positive centre stage and it works very well, as I am not competing at the moment I don't have to worry about what IASCA think.
The 8's are not fibreglass in they are mounted on a MDF platform which has then been moulded to the shape of the door frame and had "Liquid Nails" type filling to finish off the job.
The debate about seal boxes vs ported box vs Bandpass boxes is wasted on my ears as I know that I can design a box using either design and get it RIGHT every time without fail,, How good a box sounds all comes down to how good a box designer is and I consider myself to b a 1st class box designer, have a look at www.efmax.co.uk/db1218.htm or www.efmax.co.uk/box.htm
To judge any box design it has to be judged against other boxes that designer has made. I reserve the believe that a sealed box is only for those who do not know what they are doing in the designing of boxes department, because in no way will I accept the argument that a sealed box is better than a ported box or a pored box is better than Bandpass box or any other combination as it all comes down to the choice of speaker and the application that it is being applied to.
My fav box is the one in my car now. It is a Triple Chamber Dual Reflex Box and to date I have never come across anything that can touch the design and I mean NOTHING, not yet in this Millennium have a look at the whole web site in full and then see what you think.. www.efmax.co.uk
Kick panels in my six do not appeal to me and once you have listen to the sound stage in mine you will understand why it is not necessary to walk that path.
I disagree with you about the tweeters being the dominate force in a sound stage. Of course badly crossed over or position tweeters can make a system sound like crap but almost without doubt it has to be the midrange as this is where the voices are and a sound stage can be made or broken by the mids especially if the tweeters are crossed over to low down. I have mine crossed at about 5K and then they are matched sensitivity wise to blend with the mids. My tweeters work fine for me in their stock position as my mids have a range of 100Hz - 20Khz and are very special. They do most of the hard work when it comes to staging at the front. Even with them missing, and my amps automatically readjust the speaker outputs to compensate for this the 8" driver in the door and the tweeters in their stock position still sound amazing.
As for tweeters or mids in the rear NO, not a chance this is a car set up to deliver the ultimate sound stage. Very few people who have sat in can tell you where the speakers are located such is the sound stage.
As always I welcome the views and comments of others and I have appreciated yours, thank you...
didnt really look at in depth before, anyway so you have a ported box, is it tuned to a certain frequency ect. ect. , I generallly like a sub that has a flat response through all of its bandwitdth, i hate when enclosures are designed to be a little louder at a given frequency, ... Most common ported enclosures do exactly that, and just by the look of your box i thought that is what you had, but you have justified that your is somewhat different with your diagram!!!! Nice... Get back with me on its response, i may try building that one next time around!!!
Taking into account the transfer function that will exists, this is where a bass box placed in a small room i.e.. your boot or similar space, will have a natural bass lift of anything up to 12-18dB between approx. 20Hz-80Hz, and will produce a level of bass that far exceeds most peoples expectations and sound good, this box is tund to 0.00dB @ 40Hz which is low if start using -3dB figures as it's judge.
The box is also pretty flat and produces a 0.5dB shift between 50Hz - 100Hz which by any measured standard is flat.
When it comes to building these boxes, they work at their best with either two or three identical drivers. My box took forever trying to find the right drivers that I ended up with to make it work and I wouldn't personal try that route again by trying to use different size drivers.
cool, i havn't really attempted the extreme mechanics of a sub enclosure yet!!! , but I think that it is really cool that that box had a .5db fluctuation on the subsonic scale!! .. which is exactly what i have been looking for, I typically have always used sealed enclosures and everytime i RTA i usually have the standard give or take 3db down the scale. Then again the last few years i have focused more or less on center imaging and midbass response... Cant get perfect with fiberglass yet!!!
ok you audio masterminds...here's a dumb question. how do you design the "perfect" box? i am going to attempt to build a box for two 12" subwoofers...what should the volume or dimensions be for the box to achieve loud and deep bass, without, like what was mentioned earlier, the problem of some frequencies sounding much louder than others. what about placement of the speakers...should they both be faced at one direction on a flat surface? what setup will help get some good kick along with boomy lows from a pair of 12"s?
The pic doesn't do right to the colour, since it changes so much from almost blue/black to electric blue and to reddish purple. I haven't succeeded to catch that reddish purple view of it with my digi cam but it does look a lot like yours when it is on right angle / light...
My audio install is ice'd until I get my MP3 player back and my DSP fixed...
There is no such thing as a perfect box, because the laws of physics will not allow your ears to be the same as mine or the next person, so I might think I have got it right, but you might think differently.
The volume and dimensions of EVERY box is determined by the speaker parameters and NOTHING else, so in the absence of knowing which speakers you are referring to there is no answer.
A couple of years ago I was well into Bandpass Boxes, they served me well as they are one of the most unforgiving boxes to design especially when using multiple speakers.
I then hit on the idea of "Why can I not have a box that offers all of the best of each of the three main designs and none of the drawbacks".. The box in my car nicknamed the AMG dB1218 was the result.
Basically it is a designed whereby the box is modelled as a complex Bandpass box which assumes a known air space in your car's trunk/boot. It is then designed in such a way as to make the multiple speakers belief that they are in a sealed box, thus they behave in a very tight punchy and accurate way. Because the box is ported it has all the loudness of such a box and is quite efficient. Because it is modelled as a Bandpass box is goes low.
In the real world I call this type of design a Triple Chamber Dual Reflex Box. It uses either two or three identical speakers. It also has a cousin called a Five Chamber Triple Reflex Box, this uses either three or four identical speakers and it also has a Two Chamber Dual Reflex Sealed or Ported mate.
In ALL the above cases these boxes kick some serious arse.
Recently I did a design for a guy using two 15"JL Audio speakers. I designed the box for SQ yet it still hit 146.6dB at this guy's first competition.
I then did a design for the same guy using the same speakers and this time with SPL in mind, it is estimated that he will hit about 151-153dB with this new design and slightly more power,, this is what he said to me when he fired it up..>>SNIP- Erskine,
I got the box going and at first it was very loud, but now it doesn't seem to be making any noise, the woofers are moving ok...just no noise..also is it a bad sign when blood comes out of your ears. On a more serious note, the box kicks some serious a$$. With the old box my vision blurred while driving, but now I can feel my lungs vibrating as well. I can get a bottle of coke to do bunny hops on my roof and I've developed a few new rattles. All this on only one amp.
What really suprised me was how good the bass sounded when I put on Darude- Sandstorm.
Thanks Again and I look forward to getting you started on the mini box design.
Without a doubt in my mind these designs are the very best that I have come across so far in my history as a Bass Box Designer.
With my box, when you take an in-car RTA reading, this is what you get, 0.00dB @ 28Hz, that is LOW.
139dB @ 300wrms @ 50Hz, that is LOUD
+ 0r - 0.5dB frequency change between 47Hz - 105hz, that is FLAT.
151dB @ 65Hz @ 1650wrms @ 1ohm, that is PRESSURE.
So to me this is the ultimate box design but no doubt there will be those who disagree.
I once had the UK Infinity rep sit in my living room and listen to my home set-up which is a scaled down version of my car audio set-up.. Same brand of speakers just smaller.. In his words "They are like class, I have never listen to a set of speakers so clear and so transparent and with so much accurate and seriously deep bass." I had played him Money from Dark Side of the Moon by Pink Floyd.. He wasn't just impressed he was in shock and declared that he had always thought that their more expensive reference speakers which cost then, something like £7K.UK were the best.
Todate there has been nobody from any of the High End Audio Shops in my area who has listen to these speakers who have disagreed.. But are they the perfect design.. Subjective questions get objective answers..
As for boomy lows... No thank you, I want deep accurate precise hard kicking gut rumbling bass that follows the recorded information to the letter.
As for speaker placement, it is considered that speakers that face a panel beit the side wheel arches or the tailgate itself, will suffer the least from in-car cancellation. This is where the speaker is so far away from a reflective surface that the build up of sound in such a small space cause the sound waves to interfere with each other and thus reduce the overall output from that speaker box, a bit like having two speakers with one wired out of phase. By placing the speaker close to a panel it suffers less from such behaviour.
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