If I have lets say a sound amplifer similiar to the one on this link It has two 35w loudspeaker outputs. So i'm assuming each loudspeaker will be 35W. My question is lets say I wanted to put 4 louds speakers instead and I didnt really need 35W per speaker. If I was to lets say connect two louds speakers per port in parallel, will that work? I'm assuming the wattage on each output will then just be shared. If I put two speakers on a single 35W output then each speaker will get about 17.5W. Not sure if i'm thinking this right?

 

The full wattage will be applied to each speaker, the Volume of the speakers depends on the Impedance of the coil, they should all be the same rated for the Amplifier output, if you're putting speakers in parallel, then the impedance will half, so if your amp is rated for 8 Ohms speakers, and you put two 8 Ohms in parallel, it will be 4 Ohms...
If you put 4 speakers per channel then it will be 2 ohms..


Best to keep the impedance rated for the Amplifier, the wattage can be higher rated..

 

A lot will depend on the amplifier design. Some can double their output power into half the impedance, some cannot, for various reasons. Long story short, read the specification sheet for the amplifier and it will tell you what the amplifier is capable of. Some spec sheets are more honest than others..

 

If I have lets say a sound amplifer similiar to the one on this link It has two 35w loudspeaker outputs. So i'm assuming each loudspeaker will be 35W. My question is lets say I wanted to put 4 louds speakers instead and I didnt really need 35W per speaker. If I was to lets say connect two louds speakers per port in parallel, will that work? I'm assuming the wattage on each output will then just be shared. If I put two speakers on a single 35W output then each speaker will get about 17.5W. Not sure if i'm thinking this right?

(Divide the voltage,=half the power) put two 4 ohm speakers in series equals 17.5 watts each.

 

So if I bought this amp which is known as a low impedance amp as long as the ceiling speakers are either rated at 4 or 8ohms then technically the speakers should work with the amp? In the pictures of the amp at the back where the black and red speaker wires are, it says 2x 55w at 4ohm or 2x 40w at 8ohm. I've found some ceiling speakers that are rated at 8ohms 40watts so if I connect two of those speakers to this amp it should work? Is there a limit to the distance of the speaker cable from the amp to the ceiling speakers?

 

8 ohms 40W will do ok,, no limit on distance just use thick cables to avoid losses..like 1.5mm+ size...

 

I've found some ceiling speakers that are rated at 8ohms 40watts so if I connect two of those speakers to this amp it should work?

Yes.
Note that the speaker rating is just the maximum power it can tolerate without damage.
It will be very loud, and likely have noticeable distortion at that power.

Is there a limit to the distance of the speaker cable from the amp to the ceiling speakers?

No particular limit.
But you want a wire size such that keeps the total resistance low, say no more than 1 ohm total, (both wires in series).

 

The amplifier you linked to has a real output of 2 x 25W RMS into 8 ohm speakers.
Its 2 x 40W is phoney power that is very distorted. I say it produces 40 Whats instead of real Watts.

You do not play music from the amplifier at maximum 25W power all the time. The beat can be 25W but the average will be only 2.5W which is not loud if the speakers are 4m or higher above you. The speakers will be very loud if they are very close to you.

 

The amplifier you linked to has a real output of 2 x 25W RMS into 8 ohm speakers.
Its 2 x 40W is phoney power that is very distorted. I say it produces 40 Whats instead of real Watts.

You do not play music from the amplifier at maximum 25W power all the time. The beat can be 25W but the average will be only 2.5W which is not loud if the speakers are 4m or higher above you. The speakers will be very loud if they are very close to you.

So my 8ohm speakers on the amp above will only be able to provide 2x 25W. But you are saying this wont be very loud? ceilings are not high probably under 2.5m but the distance between the two speakers will be long as it's a corridor.

 

Here is more of your link:

• Output power (8 Ohms): 2x 25W RMS / 2x 40W Max. (EIAJ Standard @ 1kHz 10% THD)
• Output power (4 Ohms): 2x 35W RMS / 2x 55W Max. (EIAJ Standard @ 1kHz 10% THD)

So it will work into pairs of 8 Ohm speakers in parallel, four speaker total. Consider what AudioGuru mentions. Most amplifiers like this never meet their advertised power. Also consider you want speakers with voice coils rated well above the max power they will ever see.

Ron

 

So ive got one of these amps and I got 2 of these speakers. Wired both speakers up and put volume on the amp at MAX and placed the speakers at either end of the space that I want to cover and it was just about loud enough. It wasn't wow but wasn't low volume either. But ideally I would want it a bit louder. Looking at the datasheet for these 5.25" speakers it seems that they are only rated at 80dB. So I can return these speakers and get some others from the same website, is there any particular one someone can recommend? What about these ones which seem to be rated at 89dB or these which seem even louder. I dont mind even changing out the amp but trying to keep to a low form factor low budget amp. Any suggestions of what to buy that will work nicely with that amp would be much appreciated.

 

The position of the volume control at maximum on an amplifier does not guarantee maximum output level. The output level will be x times the input level where x is the gain of the amplifier. If the input level is low then the output level will also be low.

+3dB of speaker sensitivity is double the amplifier power that sounds only a little louder. +10dB is 10 times the output power that sounds twice as loud.

The larger speakers will sound louder than the little speakers.

 

@Audioguru again thanks. So will the following speaker https://cpc.farnell.com/mcm-custom-audio/50-14015/ceiling-speakers-8-pair/dp/LS04685 work with the amp i linked to originally? will this be the loudest option for this set up?

 

Yes, two 8" speakers will work fine with the amplifier and will be the loudest, but every speaker needs to have an enclosure. What type of ceiling? Drywall will be fine but an acoustical ceiling tile needs to have an enclosure over the rear of the speaker.

 

Yes, two 8" speakers will work fine with the amplifier and will be the loudest, but every speaker needs to have an enclosure. What type of ceiling? Drywall will be fine but an acoustical ceiling tile needs to have an enclosure over the rear of the speaker.

It's suspended ceiling white foam like tiles. So I need to cover the rear of the speaker? With what? What's the downside of not putting an enclosure on the other side?

 

A ceiling speaker usually has a "backbox".
The enclosure or backbox prevents sounds from the rear of the speaker coming around and cancelling low frequencies from the front.

 

A ceiling speaker usually has a "backbox".
The enclosure or backbox prevents sounds from the rear of the speaker coming around and cancelling low frequencies from the front.

Thank you. Is it normal for the amplifer to make a slight buzzing/humming noise when it is turned on even though nothing is being played through it?

 

No, it is not normal for an amplifier to make a slight buzzing/humming noise from its speakers, especially when its input cables are not plugged in (maybe the input cables are poor quality?).
A poorly made power transformer inside the amplifier might make the noise when the amplifier is turned on.

 

No, it is not normal for an amplifier to make a slight buzzing/humming noise from its speakers, especially when its input cables are not plugged in (maybe the input cables are poor quality?).
A poorly made power transformer inside the amplifier might make the noise when the amplifier is turned on.

Got two issues, first is that the amp itself is making a buzzing sound (not from the speaker but the unit itself is buzzing regardless of output) Second is that one particular audio gateway that i'm plugging in as the input creates buzzing noise when it's not playing anything. If it's playing a file even if it's blank then it doesn't make the sound at all. Is that amplifer faulty?

 

The buzzing from the transformer inside the amplifier is caused by a poorly made transformer.
Since the noisy audio gateway is silent when playing then it (not the amplifier) produces the noise when not playing.