I have a very odd little 'quirk' with my current setup, which is a sony CD-R3300t head unit, infinity door and headrest speakers, longmill prophet amp and 2x pro plus 10" subs.

It is something i have heard of before from others but i cannot seem to find a sensible reason why it happens.

When i press the AF button on the stereo so it displays AF OFF on the display, it cuts the power to my amp (or should i say the remote switch circuit that feeds it) so the boot box stops working, and if i press it again, AF ON and there we are, the amp comes back on.

The thing that confuses me is this, from what i can find by researching online is that AF stands for Alternative Frequency or Frequencies, which is to do with the radio tuning i would say, which by my logic should have nothing whatsoever to do with switching the remote power supply off.

Any ideas anyone??

:...would have thought o too, could be wrong though...

Auxillary Function???

AF in radio terms will shut down the speakers and connected system untill it finds a signal stronger than the current one, so for example if you are tuned to wassabi.FM and are at the very edge of the broadcasting range and wassabi.FM has no supporting broadcast infrastructure and then you turn on AF your speakers and system will be muted untill the cows come home.

e; yeah soz - af off = power off....dunno ...

e#2!

from my powers of mental investigation I have come to a conclusion:magnify:

The FM in the stereo is botched, thus causing the AF mode to pick up the slack. If you can pick up stations with AF OFF then thats this theory out the window, but if you can't this must be the case....I remember years ago that some Jap imports needed FM converters...i don't recall ever seeing AF on those radios at the time...

it could be incorrect wiring, 12v supply to amp could be mixed with 12v supply to electric antenna, so when AF is off, power to antenna is cut to tell it to retract hence power to amp stopping.

Aaaaand lap traffic nz has solved it!

In my wisdom (aka laziness) i decided to run my remote for the amp from the antenna cable as my aeriel is in the boot, just next to the amp, plus the battery is also in the boot so i only needed one set of RCA's from the head unit to get it all working as everything else was already in the boot, although, on my head unit the wire in question (that the aeriel live is wired into) is marked rem/power ant so by that logic it should do both, so god knows really lol

So basically you bodged it and now it's come back to bite you in the ass?


been there

At first i was thinkin the AF feature wire was connected to something, while it maybe should be used with bluetooth handsfree. For example, if anyone calls you then it automatically mutes the head unit. Ive seen these kinds of systems, but well. Its solved already

Started to make a new topic but then this old one i made came up, so its bump time.

The beema camw with a vibe space 15" sub (rated at 3600w) and a JBL GTO14001 mono amp, but its the amp that is puzzling me.

despite it being clearly labelled as a mono amp, there are 2 sets of speaker connections on it its laid out in the usual way that a 2 channel amp is, like this

|+|-|+|-|

Yet the manual that i downloaded for the amp says the following...

1200W RMS x 1 Channels at 4 Ohms
1500W RMS x 1 Channels at 2 Ohms

But thats all it says, no further info, so, would i be right in thinking that the first set of connectors is the 4 ohm channel and the 2nd set is the 2 ohm one, or is that incorrect, the only reason i ask is because when i moved the box when i picked the car up (needed to get shopping in the boot) i managed to pull the wires out of the amp (screws werent done up very tight) and i dont know what i need to put where and googling hasnt helped me, my first thought was use the end 2 connections, but then i thought no, because thats how you bridge a 2 channel amp, so i then thought well ill either use the first set or the second set of connections, but theres no noticeable difference regardless of which ones i use, so then im thinking again, well, do i bridge it like i thought i should, but would i then be mixing a 4 ohm and 2 ohm channel?

The main point being that its not even that loud, it rumbles a bit yeah, but i was expecting big bad boy bass that rocks the car, but i cant get that, my sony xplod 10" sub and 600w single channel amp i had in my fiesta was louder than this is.

Sorry if this is really thick, but i was expecting a £750 sound system (thats what it cost my mate when he bought it) to be a bit more impressive than this, many thanks for any help.

A lot of mono amps have 2 sets of terminals, both internally linked, to make it easier to wire stuff up (be it for wiring multiple voice coils or subs)

Easiest way is to use a multimeter on the continuity setting to work it out - but my Vibe A7 is done like this (mono, 1 channel, but 2 sets of +/-).

Quote from danthebangerboy :

But thats all it says, no further info, so, would i be right in thinking that the first set of connectors is the 4 ohm channel and the 2nd set is the 2 ohm one, or is that incorrect

That is incorrect - you dont have a 4Ω / 2Ω channel, you have a channel which you give an xΩ load, which will then give you yW of power.

I would expect the Vibe sub to be a DVC, probably 2x2Ω. You need to make sure it's wired down to the right impedance to make sure that your getting the most power from your gear (you'd be surprised how much stuff isn't!)

Million more factors to bass than power, though...

It is usually for high power speaker inputs. In the case of older car audio some head units had no RCA outputs so amp makers had inputs from the speaker cables (usually wired in parallel to the speakers). The amp then took the low frequency from the stereo signal and converted to low pass mono for the sub.

My cars stereo goes to about 139.2db

on original battery.

Quote from lap traffic nz :

It is usually for high power speaker inputs. In the case of older car audio some head units had no RCA outputs so amp makers had inputs from the speaker cables (usually wired in parallel to the speakers). The amp then took the low frequency from the stereo signal and converted to low pass mono for the sub.

If this was the case there would be more than one (normally 4 - but I've never seen a mono amp with hi-level inputs), and it would be next to the RCA's rather than the speaker outputs.

Had a look at the manual for your amp and it says

Quote :

Speaker Output Connectors
• Connect the speakers to these terminals,
observing proper polarity. Either + or –
terminal may be used.

So it doesn't matter which set you use, as like Jakg said they will be internally linked, their are just two sets on the outside for ease of wiring.
First thing would be to check your gain, and also check your RCA's, as you might have pulled one out of the amp when moving it.

Quote from danthebangerboy :

Sorry if this is really thick, but i was expecting a £750 sound system (thats what it cost my mate when he bought it) to be a bit more impressive than this, many thanks for any help.

I don't really find a reason why you should buy a single-channel amplifier when they're more expensive, and you most likely would get a bit cheaper 2-channel amplifier and bridge the connection and you would have most likely got same, if not even more power out of it.

Quote from nikopdr :

I don't really find a reason why you should buy a single-channel amplifier when they're more expensive, and you most likely would get a bit cheaper 2-channel amplifier and bridge the connection and you would have most likely got same, if not even more power out of it.

Exactly, even a 2-channel is overprized, Get like a 4-channel Bull Audio, it's basically Rainbow, but abit more unexpensive. best would getting the 2-channel Amp from JL think it's called JX750 or something like that.

Here is my setup either way

Bull Audio 4-channel for two 4''(Alpine) speakers and two 8'' ( Renegade)Speakers
Bull Audio 4-channel for two 8'' speakers ( Renegade ) 4 6,5'' Speakers, which are bridged together ( Renegade )
Bull Audio 2-channel for 2x12'' sub from JL Audio
JL Audio 2-channel for 2x12'' sub from JL Audio


All the best
D.

Quote from nikopdr :

I don't really find a reason why you should buy a single-channel amplifier when they're more expensive, and you most likely would get a bit cheaper 2-channel amplifier and bridge the connection and you would have most likely got same, if not even more power out of it.

You can't really get a high power 2 channel, and also you wont normally find a 2 channel thats capable of being bridged and running a 1Ω load.

Quote from Jakg :

You can't really get a high power 2 channel

This is obviously lie bs.

There are made many high powered ones made for single/double subs, and obivously smaller speaker systems.

Quote from Dennis93 :

This is obviously lie bs.

Show me a 2-channel that does 2kW RMS while bridged then...

EDIT - A mono amp can still run 2 subs remember, it just can't feed them different signals (which you'd not normally want to do anyway).

Quote from Jakg :

Show me a 2-channel that does 2kW RMS while bridged then...

EDIT - A mono amp can still run 2 subs remember, it just can't feed them different signals (which you'd not normally want to do anyway).

Why would you bridge a 2channel sub? that's stupid.

Quote from nikopdr :

I don't really find a reason why you should buy a single-channel amplifier when they're more expensive, and you most likely would get a bit cheaper 2-channel amplifier and bridge the connection and you would have most likely got same, if not even more power out of it.

Quote from Dennis93 :

Why would you bridge a 2channel sub? that's stupid.

.

Oh my bad, sorry

get a 4-channel then, should be ''Healthier'', obviously i would get someone who knows about it to set it up so it's playing what it should, and not too much either way.

Monoblock for subs is normally a far better option. As it gives you a lot more freedom with how you wire your subs. Most monoblocks handle anywhere from 4ohm to 1 ohm, which is great as it makes wiring multiple subs(or multiple voice coils) a lot easier as you've got a wider range of ohms to end up with. Whereas a 2/4 channel, to give the same amount of power as a monoblock would need to be bridged, and majority of these only run at 4ohm once bridged. Which means you have to find a way to wire your subs specifically to 4 ohm, their can be no error at all otherwise you're running your subs at a resistance the amp cant handle.

Not to mention most monoblocks are Class D amplifier, which is much better for bass. Less heat and a lot more efficient.