When i try to play a and b speakers it says low impedence ??????

a bit vague ?
I am assuming you are trying to connect a sub wooofer and a normal speaker of some kind. A sub woofer works for low frequencies so you may need a crossover to pass low frequencies to the subwoofer and other frequencies to the normal speakers.
The other reason may be the impedance of the two speakers being wired together may make the total impedance out of the normal impedance level of the amplifier.

If you are running three 8 ohm speakers in parallel then the total impedance would be 2.667. If running two 8 ohm and one 6 ohm speaker in parallel you would have 2.4 ohms. This will burn out your amp pretty quick. And very possible won't play at all. Though I have never attempted to play a home amp down that low in ohms. Guessing you may have an older model Denon type amp.

Hello, Go to the bottom right hand corner and click on the speaker there and adjust the volume or go to control panel and then sound and also adjust or download new drivers.

The Low Impedance setting is for when you have even one speaker with <8-ohms nominal impedance so you can use bot speaker pairs together. You still need to have an effective total (parallel) impedance of 4-ohms minimum or there may be problems like blowing up the amps.

Press and hold the SPEAKERS A or B button until LOW IMP lights or goes out, as required.

Press either button to toggle that speaker pair on or off.

It's in the manual page 14, 22 and 25.

First of all find out the recommended speaker impedance for the receiver. Then find out the impedance of the speakers you are using along with it.
Simple rule is the speaker impedance can be higher but not lower than the recommended value. If it is so the receiver will run hot and if you turn up the volume higher it will run even hotter and then the protection circuit will cut off the Amplifier output to prevent burn out of components. Even if you have one defective speaker this cut off can happen. To confirm defective speaker -- disconnect one speaker at a time and turn on the amplifier and play it at cut off volumes.If by disconnecting one particular speaker the Amplifier does not cut off -- THAT SPEAKER HAS A SHORTED COIL and needs replacement.

Low Impedance is not a suggestion, it is a WARNING. Your receiver is telling you it senses TOO LOW a load and it's trying to protect itself from damage.

Speakers A& B are running in parallel, so their combined impedance, X, is found by using the formula: 1/X = 1/A + 1/B.

In other words, two 8-ohm speakers in parallel would yield a 4-ohm load.

If your speakers are identical, try running them in series on one speaker output pair. That would keep the impedance safely high.

Protection LED on, no output? Amplifi er is very hot = thermal protection is engaged. Test for proper
impedance at the speaker terminals with a VOM meter (see the diagrams in this manual for minimum
recommended impedance and multiple speaker wiring suggestions). Also check for adequate airfl ow around
the amplifi er. Amplifi er shuts down only while vehicle is running = voltage protection circuitry is engaged.
Voltage to the amplifi er is not within the 10–16 volt operating range. Have the vehicle’s charging and electrical
system inspected. Amplifi er will only play at low volume levels = short circuit protection is engaged. Check
for speaker wires shorted to each other or to the vehicle chassis. Check for damaged speakers or speaker(s)
operating below the minimum recommended impedance.
No or low output? Check the balance control on source unit Check the RCA (or speaker input) and
speaker output connections.

There's a reason they don't want you running parallel speakers - possible impedance being too low. You would have to CHEAT and attach them both to the same terminals to hear them at the same time. Then you run the risk of presenting too low an impedance load to the amplifier and possibly having it go into protection (turning the speakers off) sometimes. It might also just work if you're lucky and not trying to entertain the neighbors. ;-)

This is similar to protect mode in that the amp has detected a short in the output and has shutdown to prevent damage. Without seeing the unit, I'm a bit hesatant to suggest repair tips. At this point, I would suggest you get a detailed estimate from a local shop. We should be able to guide you through the actual repair once the results are posted here.

Dan

you may be using an equalizer? try to pop-up the volume with all tone controls in flat mode. see if it still cuts off. if this is the first time youencounter this then something must be wroing with either your speakers or your amp. unless your ventilation is not good enoughg, you can also try placing a blower on top of your unit to cool it down