26 replies to this topic

[Mr. Drifter]

Yet another thread for advice :3

Ok, So I'm going to get some pods made up in my kicks, but wanted to know what the best design would be.. Eg 15l sealed and facing the opposite side head/ high area near the head

The speakers are Rockford prime R1653.
Car is 1977 Honda civic sedan
There are no cavities behind the trim panels to tap into.. it's pretty much just plastic over metal :|
I'm going to be using these later on for splits, so that may be a factor too...


Cheers, and sorry for all the questions, just want to make sure I don't go in without any knowledge

Edited by Ben-Drifter, 09 February 2012 - 02:43 AM.

[shiny_car]

Bigger than 15L will help with midbass. Probably up to 30L. But the smaller it is, the less midbass you'll have, so you may need to rely on the subwoofer to play a bit higher, say to 150Hz.

The angle will take some experimenting. The 'opposite seat headrest' is a good place to start. It just depends how well the speakers play off-axis, or whether they tend to 'beam' and need to be very on-axis.

[Mr. Drifter]

Ah true, thanks for that shiny

I'll have a chat with the guys at aa, see how large they think we can shove in there, without interfering with pedal room and what not
Not sure how much the rockfords beam, but we can only hope not much.
and the sub option may be one to consider.. might get kicks beating through the sub. wewt

[Mr. Drifter]

ok, excuse the double post, but i felt this question didn't deserve it's own thread, for sillyness...

But, a subwoofer free air, wouldn't sound anywhere near as loud as when it's in a box, would it?

[shiny_car]

It can, presuming the sub can handle good power, that the amplifier is powerful enough, and the cone has decent excursion. Same factors as with a normal sub. So, no reason it can't be loud.

[Big_Valven]

It'll work, but if you like the odd street beat, you will probably find most ordinary subwoofer drivers won't cut it IB.

[Mr. Drifter]

yeah, I had it just sitting in the boot off the amp, and it wasn't very loud at all :|

But yeah, thanks for that ^^

Edited by Ben-Drifter, 30 January 2012 - 12:36 PM.

[Big_Valven]

Oh, you can get it much better than that, by actually having a baffle ie the parcel shelf, but there are still limitations.

[Mr. Drifter]

ohok, fair enough
Thanks callum and... (doesn't know shiny's name, so will just call him shiny) Shiny

[shiny_car]

Ben-Drifter, on 29 January 2012 - 10:05 PM, said:

But, a subwoofer free air, wouldn't sound anywhere near as loud as when it's in a box, would it?

Ben-Drifter, on 30 January 2012 - 12:34 PM, said:

yeah, I had it just sitting in the boot off the amp, and it wasn't very loud at all :|

Ah. 'Sitting in the boot' is not actually a proper 'free air'/infinite baffle installation, despite the literal interpretation. In a hypothetical environment (ie: for the purpose of explanation), infinite baffle would entail a huge open space/room, divided into two by an 'infinite size baffle'; imagine a huge gymnasium with a dividing wall, that divides the place into two. That's the concept, but even bigger in the hypothetical world. Now mount your sub onto the baffle. The result is having 'the front of the cone on one side' and the 'rear of the cone on the other side', with no communication between the two sides.

Applying this to a car, the idea is to have the sub mounted either on the parcel shelf, or on a baffle board where the rear fold-down seat is.The 'two spaces' become the boot, and the cabin. In the car, the boot ends up being the enclosure for the sub, instead of a conventional subbox, but more importantly you must seal off the boot from the cabin (ie: seal over all air gaps) to create those two separate air spaces.

You can gather that your attempt is far from a proper free-air/IB installation. The sound waves off the front of the cone are mixing with the waves off the rear of the cone, resulting in mega phase issues and negligible subbass. So, it wasn't proper free-air, and therefore not proper sound, and therefore an incorrect presumption that free-air is not very good/loud.

And as discussed, a sub properly designed for free-air/IB offers the best results. These typically have a pretty high Qts spec (>0.50).

Ben-Drifter, on 30 January 2012 - 01:14 PM, said:

Thanks callum and... (doesn't know shiny's name, so will just call him shiny) Shiny

"shiny" will do.

[Mr. Drifter]

Ah, of course xD My bad for misinterpreting :3

But that does make lots of sense, thanks shiny ^^

[Mr. Drifter]

Another question, not worthy of making a thread over...
The amp has a switch on the speaker channels which is '12db-24db' and it's db slope or something.. no idea what it's for :| maybe frequency slope?
Had a look at the online manual (mine didn't come with one) and it doesn't mention it as far as my skim reading could tell.. Anyone know what it is? what it does, and what I should set it as?

Cheers

[Spink!]

That will be your crossover frequency slope, I'm not sure what sort of front stage you are running so can't help, but if it's passive I'd say the 12dB will be suitable, 24dB would be pretty steep to run to you midwoofer and tweeter.

[Mr. Drifter]

ohok, fair enough, thanks for that
guess I'll keep it on 12db then. thanks for that man

[Mr. Drifter]

So, Another question for the fantastic short question thread..

If the speakers pop when the amp turns on, is this a bad sign? if yes, how does one fix said issue of speakers popping? If no, how does one fix said issue?

cheers ;D

Edited by Ben-Drifter, 09 February 2012 - 02:45 AM.