4 replies to this topic

[ryzaa]

Hi guys, just thought it would be useful to have a thread about your loud system, and how it can affect the rest of your system. I would like to explore it a bit myself, and have a few ideas on how to combat some of the effects, but am also interested in others theories and ideas.

Basically I am in the process of purchasing a new vehicle. Something that I will use as a daily. Coming from an SPL background, I of course want it loud. The type of music I listen to, means that it will have to play low. However I am also a bit of an SQueer, so itll be all about the quality up front and a bit of fun down the back for when I feel like floating midgets in my door or not being able to see out my windshield.

Anyways, moving on, I have been concerned for a while on what will happen with large SPLs on my beautiful, expensive front stage. Obviously I do not wish to compromise them in any way, shape or form. I have seen the damage that loud daily set ups do to cars, blowing windshields, ripping welds, tearing sheet metal. What is to stop this from happening to my 1 inch silk domes at the same levels?

So anyways, I am just working on 158 as a max that could be achieved, last time I checked around the 160 mark was highest bass race scores, not saying I am aiming for that, but it is always good to have some head room, plus others may read this who are aiming much higher. I am more likely to be in the 40s.

Distorted waveforms due to air variances and the like can cause fluctuations, lets be safe and assume 3db, so that puts us in the range of 155-161 [realistically 145-151 ]
Using appropriate methods of conversion, we can turn SPL into PSI, 155 should be around 0.15-0.2psi and 161 around 0.35psi. A bit of variance there, but SPL is an exponential function, so it is to be expected to see such an increase over a [relatively] small increase in SPL.

So by my calculations [Its a long day at work]
pi[3.1415] x r[0.5]^2 x 0.2psi
= 0.157 pounds
~ 71 grams

I close enough to 70 grams of force being exerted on my 1 inch dome tweeter at 155db, it is a bit more then this, due to the spherical nature of the tweeter, but that is taking it a tad far at this point.
Now, we have the variance to take into account, so at 161, we are close on double the force, at 0.35psi, its close to 124 grams of force on the tweeter.

Now I am wondering if anyone knows what sort of force, or how to work out how much force the average soft dome tweeter can with stand...
I will also be using Paper cone mid ranges and mid bass's, to try and combat the force against them, I will experiment with them in smaller then recommended [sealed] enclosures first, so as to try and combat the force against them. Obviously the nature of a moving coil in a magnet will ensure some force against the force on the cone, and then having them in sealed enclosures should help also.

Can anyone think of any other measures to try and combat such an issue, is it really not an issue at all? Or will I have to scrap any ideas of having a nice front stage using the components I want and turn to PA drivers and super tweeters?

Any other thoughts/ideas/suggestions by people are much appreciated and I hope that you may gain some knowledge or information from this thread as well.

[RAD]

I'll simply say, anything around 150db or more is silly trying to combine it with a nice front stage.

So i had Polk Momo's up front in my excel, which did 150@32hz. Pushing the subs hard would simply cause the midrange drivers to move sympathetically to the bass. This might not happen (or as much) if you were to put the midrange drivers in a sealed enclosure, but in the doors the poor polks nearly bottomed out. And there was'nt much sound to be heard once the windshield started to flex.

IMO grab a series of nice coax drivers (morel/hertz/arc/focal etc) to keep up with the subs, perhaps an 8" to give you some semblance of midbass, install said coax drivers to give your desired stage height and width, and don't stress about SQ in a groundpounder.

[ryzaa]

Hey Ross, thanks for your thoughts. I can see how having them venting into the door can have a negative effect on your front stage. For the most part, it wont be a groundpounder, SQ is the main priority in it, but the fun of a loud system taunts me all the same.

The Team Ampl Laser is doing over 150 at the moment at 34hz, with 4 6.5" woofers in a sealed pod currently, and they are barely moving at full noise, which has led me to believe that I may be able to work it by using smaller sealed enclosures then what is recommended by the manufacturer. Bracing is going to be a major part of this car well before it even starts to get loud, So as to eliminate flex as much as possible before anything starts to give. I have seen enough cars and watched them tear themselves apart to know a few of the short comings of them, and hopefully with experiments in the laser as well as my own car we can stop the worst of it. I will most likely be competing in SQ and enjoying that more often then I will the rippling of sub bass through my body..

I think perhaps the best start would be to try out a few different things in the laser [after it actually gets put back together all sealed up properly], to try and simulate what will be happening in my car, so I can experiment and document what happens to woofers in various situations. I dont think that will be of most concern however, more the 1" silk domes and how they are affected.

I shall experiment and try nonetheless, just wary of what could happen.

[D34M0N.inc]

Or use some drivers like the Anarchy 6.5" drivers to try counteract the cabin pressure with its high xmax and motor strenght could help? Just an idea anyway.

[ryzaa]

Just spent a bit of time experimenting with various woofers in various boxes inside the laser, doing 150s from 30-60 odd hertz..
Ported box = no no for woofers, bottoming out, etc.
Sealed box was fine, nearly no movement
And free airing was seeing next to no movement either.

Couldnt see anything happening to the tweeters, no visible movement on silk domes, but we shall see how they hold up I suppose..