Trouble Setting amp gains

[caintrain 0]

FI BTL 15" dual 2 ohm, wired to 1

Rockford t1500bd

The birth sheet wattage is 1700, so after calculation the voltage output should be 41.23. I tested with a dmm to find the voltage and at this level the sub is not as loud as a btl should be.

also the amp gets to this 41.23 volts with no punch eq, and very little gain.

could anyone explain this because this sub should take all the power of this amp and then some but is not sounding like a btl right now.

with twice the voltage output the sub still sounds good, is loud, but the amp gets extremely hot.

[raolito1980 2]

FI BTL 15" dual 2 ohm, wired to 1

Rockford t1500bd

The birth sheet wattage is 1700, so after calculation the voltage output should be 41.23. I tested with a dmm to find the voltage and at this level the sub is not as loud as a btl should be.

also the amp gets to this 41.23 volts with no punch eq, and very little gain.

could anyone explain this because this sub should take all the power of this amp and then some but is not sounding like a btl right now.

with twice the voltage output the sub still sounds good, is loud, but the amp gets extremely hot.

Check your ground. If you dont have it grounded properly it could be putting strain on the amp to push it. 4 gauge wiring? You double checked how you wired the sub?

[caintrain 0]

Will it matter if the amp ground is 5 awg, and the power is 4?

[jcarter1885 995]

Will it matter if the amp ground is 5 awg, and the power is 4?

No matter what your wiring you want you power and ground wire to be the same size and if you want to or have to then you make you ground wire bigger than your power wire.

So in your case I would use the 4 awg for the ground wire and 5 awg for the ground wire until you can get matching wire sizes. Just my logic and with that amp try to use 1/0 awg if you can.

Check your DMM to make sure its on the right setting as well.

[FIBLIntrigue 0]

This Is My system...... will low input voltage put stress on the amp??

[sandt38 448]

at this level the sub is not as loud as a btl should be.

And exactly how loud is that supposed to be? Every install has different variables that will affect the sound quality and output of it's components differently. If not, every competitor with a BTL would have the exact same score every time.

Perhaps you just expected too much... Perhaps it is just an average install and you are expecting a competitor's install type output.

If the output voltage is reading correctly, the amp gains are set right, period. It is now time to focus on the installation.

Edited July 7, 2010 by sandt38

[inkfx 3]

I bet if you upgrade to 1/0 wire you will notice a difference. 1/0 is going to handle that power a lot better.

[FIBLIntrigue 0]

How do I Upgrade To 1/0 Guage when it has 4 guage connections that barely eat my 4 guage

[imhungnurnot 9]

How do I Upgrade To 1/0 Guage when it has 4 guage connections that barely eat my 4 guage

They make adapters for this purpose. Or you can run the 1/0 to a distro block that is at the most 1.5 feet away from your amps, and down size the wire to 4 awg. Length is a huge factor.

[kirill007 52]

Will it matter if the amp ground is 5 awg, and the power is 4?

Yes it does matters, make sure the ground and power wire is the same size.

If it get's to 41.xx Volts, then the gain is set correctly.

It's you're install that is not good enough, or it's the car that it's in.

NO need to turn it up past 41.23V, that's when it will clip.(maybe you're already clipping a little bit, because of voltage drop but that doesn't really matters.)

In what box is the BTL?

Is it a trunk install?

[caintrain 0]

it is a trunk install and it is in a 3.5 cube box....calculated on RE calc. I know this is bad and since i have made a box calc and have gained substantial knowledge through this site. the box cant get any bigger and fit in the trunk tho.

[caintrain 0]

Also when doing the gain setting calculation...=SQrt(RMS WATTAGE*IMPEDANCE) is the impedance the sub impedance or what it is wired to?

[Impious 1,476]

The impedance the subwoofer is wired to.

This thread may help you;

gain setting questions - SSA Car Audio Forum

[caintrain 0]

Thanks impious, OK. we changed out his 5 awg, to 4. This is still not helping. With this amp and tis sub I feel it should be way louder. The amp reaches its calculated output voltage with the punch eq set on zero and the gain on just below level 3. I dont feel like the amp is kicking out the 1700 watts it is supposed to, do u think with 0 awg and big three and another battery it will be able to kick out more wattage at this 41 volts. also i tried measuring the ampheres so i could see what wattage (voltsX amps) it was putting out but i am unsure how to do this, anyone have pics or vids with this. I am really stumped here.

Thanks guys.

[sandt38 448]

Thanks impious, OK. we changed out his 5 awg, to 4. This is still not helping. With this amp and tis sub I feel it should be way louder. The amp reaches its calculated output voltage with the punch eq set on zero and the gain on just below level 3. I dont feel like the amp is kicking out the 1700 watts it is supposed to, do u think with 0 awg and big three and another battery it will be able to kick out more wattage at this 41 volts. also i tried measuring the ampheres so i could see what wattage (voltsX amps) it was putting out but i am unsure how to do this, anyone have pics or vids with this. I am really stumped here.

Thanks guys.

As was already stated, if you have achieved the recommended voltage, the gains are set. The amplifier is delivering it's output voltage, and the sub is providing the required load. The electrical demands have been met. End of story, period.

Every install has different variables that will affect the sound quality and output of it's components differently. If not, every competitor with a BTL would have the exact same score every time.

You just expected too much...

Start working on other install variables and stop, stop, stop with the gains before you have a dead BTL and an even more dissatisfied friend. There is more to installation then just putting an amp in, building a box and tossing it in a car.

Edited July 8, 2010 by sandt38

[caintrain 0]

Like I said, I want to figure out what wattage its putting out. And i asked about other electrical upgrades and if it would help the amp put out more wattage at this volt level....what else would you reccommend i look into sandt38?

[sandt38 448]

The wattage will not change. The load will be the same no matter what, unless you buy different subs.

The installation issues at hand could be sunwoofer placement, firing direction, a poorly designed or constructed box, box flex, vehicle panel flex, the trunk being too sealed off, poor crossover settings (including but not limited to SSF settings), among many, many other variables.

[caintrain 0]

OK...i know this is going to annoy you but i am asking anyway...should i test the voltage with the sub hooked up to the terminals, or some other 1 ohm resister?

[caintrain 0]

And the setting on the dmm should be on VAC right?

[imhungnurnot 9]

And the setting on the dmm should be on VAC right?

Just read the noob proof tutorial pinned to this section of the forum.. It was pinned because it was useful.. so READ!

[KU40 173]

if you want to know wattage, you need a clamp meter. Just realize that at every frequency the amp will be putting out different amounts of power because the sub's impedance changes with frequency. So with the same gain setting you may be getting 500 watts at 40 hz but 1000 watts at 60 hz.

[sandt38 448]

if you want to know wattage, you need a clamp meter. Just realize that at every frequency the amp will be putting out different amounts of power because the sub's impedance changes with frequency. So with the same gain setting you may be getting 500 watts at 40 hz but 1000 watts at 60 hz.

FWIW it is really best to model the system in an enclosure program, check the impedance graph, find the lowest impedance by frequency and run tones at or around this frequency. The point at which the dynamic impedance is lowest is the point at which the amplifier will be delivering the most power. Also, it is worth noting, the sub will typically reach it's lowest dynamic impedance at or around the enclosure's tuning frequency in the case of a ported box.

But it must be stressed that just because the system is not putting out the birthsheet power of 1700 watts doesn't mean you can turn up the gains any more. Dynamic impedance will actually never reach the manufacturer rated RE... or I should say, I have never seen a case where it has. But just because the system will not make the rated 1700 watts, doesn't mean you can turn the gains up to that point. If you turn the gains up beyond the point where clipping occurs, it will clip no matter what the measured output actually is.

[caintrain 0]

And the setting on the dmm should be on VAC right?

Just read the noob proof tutorial pinned to this section of the forum.. It was pinned because it was useful.. so READ!

I did read that but it leaves important small details out, also it does not tell you how to measure amps in a circuit so i can know the actual wattage being put out.

[KU40 173]

if you want to know wattage, you need a clamp meter. Just realize that at every frequency the amp will be putting out different amounts of power because the sub's impedance changes with frequency. So with the same gain setting you may be getting 500 watts at 40 hz but 1000 watts at 60 hz.

FWIW it is really best to model the system in an enclosure program, check the impedance graph, find the lowest impedance by frequency and run tones at or around this frequency. The point at which the dynamic impedance is lowest is the point at which the amplifier will be delivering the most power. Also, it is worth noting, the sub will typically reach it's lowest dynamic impedance at or around the enclosure's tuning frequency in the case of a ported box.

But it must be stressed that just because the system is not putting out the birthsheet power of 1700 watts doesn't mean you can turn up the gains any more. Dynamic impedance will actually never reach the manufacturer rated RE... or I should say, I have never seen a case where it has. But just because the system will not make the rated 1700 watts, doesn't mean you can turn the gains up to that point. If you turn the gains up beyond the point where clipping occurs, it will clip no matter what the measured output actually is.

Realize that the reason you can't always get the full rated output is because of the impedance increase. If you just pick, say, 40 hz to try and check output power, and find that your sub has an impedance of 2 ohms at that level, there's no way to get the full 1700 watts at that frequency without heavy clipping. If your amp is rated at 750 watts at 2 ohms and 1500 watts at 1 ohm, you can't try for the 1500 watts just because you have your subs wired for a 1 ohm load at the amp. The actual impedance at 40 hz would be 2 ohms, so you could expect 750 watts. If you try to increase the gain to get 1500 watts at that frequency, you will drive your amp well into clipping.

If you want to get full output, it's not a bad idea to hook up an oscilloscope and run a test sweep over the frequency range of the sub to see if the amp clips anywhere along there before turning the gain up to get more power.

And again, you need a clamp meter. That's why when people say they have tested the output of the amplifier, they say they clamped the amp.

[kirill007 52]

it is a trunk install and it is in a 3.5 cube box....calculated on RE calc. I know this is bad and since i have made a box calc and have gained substantial knowledge through this site. the box cant get any bigger and fit in the trunk tho.

Is that NET volume or gross volume?

How much port areea, and to what is it tuned to?

Because the BTL doesn't sounds loud enough to you doesn't means it's not getting the 1700 watts.