28 replies to this topic

[shizzle]

Heya,

Saw this on a forum I used to visit back in South Africa.

I am not convinced that they would sound that amazing, but the installer and owner say they do. They are both highly respected in the scene over there, so would imagine they sound top notch.

http://www.speednsound.co.za/forum/viewtop...47&start=75

Interesting to say the least. Although I would imagine the freq. response would be dismal for the mids, and would not being used as intended.

Its about half way down the page

[hardyards]

Wowzers!

Im confused, is that the midrange behind the tweet?

apart from that the install looks the goods

[Tiger]

An inverted midrange behind a tweeter?

VERY interesting. I'm curious to know what his theory is behind them A Pillars! Judging by his install, he looks like he's got a fair idea about things, that's for sure. And top audio gear he's using too!

Edited by Tiger, 13 February 2010 - 10:19 PM.

[shizzle]

yup, I am also confused, but I like originality, and won't bash it till I heard it (not that I can).

I would have thought though the response would be crap form the mid. The frequency it plays would be best on axis, from what I have learnt. He did admit that he had to cross it @3500hz, as everything above that went to a ball of crap. I would want to cross a small mid higher than that.
I also would think the back of a mid has alot of breakup, add to that a tweeter behind it, and the bracing on the sides, all I can say is hmmmmmmmmmm.

Anyhoo, its still original, although it looks like those snorkels you get on 4x4, but just on the inside

[~thematt~]

I've heard cars with mids and tweets that close to your face before, and its an interesting sound. Tonally, yeh, it can come across as sounding nice. One of our installers in WA used to do that stuff for a living (preferable mounting in the A-pillars). However, you'll never achieve the total picture across the entire spectrum.

Unfortunately though, its simply evidence that the installers dont understand the basics behind what they're doing. I'm talking the basics of physics, sound propagation etc.

Instead, they take systems that sound bad, and tune the crap out of them to sound good. That makes them skilled, and good on 'em. However, I've seen and heard systems since that work with the basic fundamentals and sound better after installation (before tuning), so that when you tune them, they end up being far superior.

In the end, these are just a visual blight, despite how much effort and customization goes into it.

[jas]

i wounder if this would sound even better with a small car tweeter rather than the adapted home audio driver. Then you could place a cone over the back of the magnet and try and have a smooth transition to the tweeter (imagine a phase plug with the tweeter in the end of it with the cone shape starting at the end of the 4inch drivers basket/magnet assembly in order to get the sound defrating forward as well as sideways). A small tweeter like a 19mm JL C5 or something small like that might work better to a certain db output point. I know the big form tweeters sound much much better but for this application maybe its a step backwards.


anyway great idea and setup well done to the installer for doing such an unusual install. Personally i would never want to be in this car when its moving with such big pod near your head. Its a little on the dangerous side for a front impact crash.

Edited by jas, 14 February 2010 - 12:04 AM.

[FreQuence]

Now thats taking "in your face" sound to another level. Surely having speakers cm's away from your face cant be a good thing?

[2LOUD2OLD]

boot looks nice though

[Luke352]

jas, on Feb 14 2010, 12:03 AM, said:

i wounder if this would sound even better with a small car tweeter rather than the adapted home audio driver. Then you could place a cone over the back of the magnet and try and have a smooth transition to the tweeter (imagine a phase plug with the tweeter in the end of it with the cone shape starting at the end of the 4inch drivers basket/magnet assembly in order to get the sound defrating forward as well as sideways). A small tweeter like a 19mm JL C5 or something small like that might work better to a certain db output point. I know the big form tweeters sound much much better but for this application maybe its a step backwards.

Agreed would've been better if they had mounted the mid conventionally and then placed a small tweeter over the centre of the cone, so as to try and get a point source setup, which is what they were trying to achieve obviously.

That is actually a Car audio market tweeter though, it's the new DLS Scandanavia tweeter and midrange.

[Pulse-R]

looks like an air circ knock-off.

[Luke352]

Pulse-R, on Feb 14 2010, 12:27 PM, said:

looks like an air circ knock-off.

Probably, DLS doesn't build any of there own stuff, they just get it built to there specs by other people. The midrange looks very similar to a Vifa TG9.

Edited by Luke352, 14 February 2010 - 12:33 PM.

[xMplar]

looks like some sort of passive radiator type deal like a push pull design interesting i wonder how it sounds tho if nothing else it looks unique

Ren
xMplar

[shizzle]

This is the reply from the guy who did it :

To answer your question properly, I have to give you some fun work to do.


Remembering that speakers are wave propagators, and that sound is a series of waves traveling through the air in the car, here is a nice applet with different settings possible. Move the source to the middle, then click on the 3d box
http://www.falstad.c...pple/index.html


then choose 2 sources, 2 frequencies in the 2d screen, move them towards the centre of the tank, then click on 3d

notice:
1. areas of exaggerated peaks
2. and areas of exaggerated dips
3. and areas of nulls(complete wave cancellation)

so the theory behind the design is that of coherent wave fronts
on the downside, if not done correctly, you can also end up with modulation. To give a really rough idea of modulation: it’s similar to what happens when you speak into a fan up close.

In home hi-fi situations the effect of wavefront and source coherence is slightly less important because you sit much further away from the source, but in the car, especially with mids and tweeters on the dash, we can – nearly always - hear the 2 separate mid and tweeter sources which plays havoc with all of the stereo holographics we are trying so hard to achieve.
Generating a coherent wavefront goes a long way towards a more coherent sound(many drivers acting together to sound like one) which is why I ended up doing what I did.

I hope this answers your question

[Luke352]

They would be very close to coherent if he had a small tweeter mounted just off the cone, but with his setup with the tweeter several inches infront of the mid they have lost all the benefits, not to mention all the reflections the wave front of the mid is going to experience. Using his ripple tank thing move one source further out and you'll see what I mean you get multiple areas with cancellation and modulation etc...

[shizzle]

yup, I agree 100%, just thought I would share his reasoning.