Bigger Amp Needed?

Sep 22, 2021
5
0
20
4x Jamo 265 D:
-Short Term - 265w
-Long Term - 150w
4-8 ohm

4x Rotec Professional:
-100w
-8 ohm

Amp: Kenwood A-45
-Power output: 40 watts per channel into 8Ω (stereo)
-Frequency response: 20Hz to 50kHz
-Total harmonic distortion: 0.02%
-Input sensitivity: 1.5mV (mic), 2.5mV (MM), -200mV (line)
-Signal to noise ratio: 74dB (MM), 96dB (line)
-Output: 200mV (line)

10 Channel Speaker Switch Selector:
-4-16 ohms
-100w per channel max


Ok so from what I know when you mix speaker wattage the max wattage you can achieve is the lowest wattage if the group of speakers.
So in my case the 100w of the Rotec will bring the Jamo 150w to 100w? Is this right?

I have these speakers going through a speaker switch selector 100w per channel but my amp is 40w per channel so would this mean that the max I can get out of my speakers with this amp is 40w?

If so to get the best out of my speakers should I get a power amp capable of 100w per channel?
 

shadders

Well-known member
Nov 19, 2009
212
130
18,970
4x Jamo 265 D:
-Short Term - 265w
-Long Term - 150w
4-8 ohm

4x Rotec Professional:
-100w
-8 ohm

Amp: Kenwood A-45
-Power output: 40 watts per channel into 8Ω (stereo)
-Frequency response: 20Hz to 50kHz
-Total harmonic distortion: 0.02%
-Input sensitivity: 1.5mV (mic), 2.5mV (MM), -200mV (line)
-Signal to noise ratio: 74dB (MM), 96dB (line)
-Output: 200mV (line)

10 Channel Speaker Switch Selector:
-4-16 ohms
-100w per channel max


Ok so from what I know when you mix speaker wattage the max wattage you can achieve is the lowest wattage if the group of speakers.
So in my case the 100w of the Rotec will bring the Jamo 150w to 100w? Is this right?

I have these speakers going through a speaker switch selector 100w per channel but my amp is 40w per channel so would this mean that the max I can get out of my speakers with this amp is 40w?

If so to get the best out of my speakers should I get a power amp capable of 100w per channel?
Hi,
The Jamo D 265 are specified as 8ohm speakers, with a sensitivity of 95.2dB.

The SPL from the speakers will be 105.2dB for 10watts usage from the amplifier, scaling up to 108.2dB for 20watts, and 111.2dB for 40watts.

The amplifier power is more than adequate to drive 2 Jamo speakers (stereo).

For the Rotec, i cannot locate sensitivity details etc.

The maximum from the amplifier is 40watts, but with the Jamo speakers, you can achieve high SPL.

Regards,
Shadders.
 
Sep 22, 2021
5
0
20
Hi,
The Jamo D 265 are specified as 8ohm speakers, with a sensitivity of 95.2dB.

The SPL from the speakers will be 105.2dB for 10watts usage from the amplifier, scaling up to 108.2dB for 20watts, and 111.2dB for 40watts.

The amplifier power is more than adequate to drive 2 Jamo speakers (stereo).

For the Rotec, i cannot locate sensitivity details etc.

The maximum from the amplifier is 40watts, but with the Jamo speakers, you can achieve high SPL.

Regards,
Shadders.
Hi
Thanks for your response. I’m ashamed to say that after over 30+ years of just plugging speakers into Amps and hoping for the best I’m only now starting to look into the technical side of things so I’m not quite sure what some of your response means?
I am looking at running all speakers at the one time (x8)
1. Why does SPL matter?
2. Could I get more out of the speakers if in had an amp with more than 40watts per channel? As I say I use a Speaker Splitter box to use all x8 speakers at once.
Thanks
 
Last edited:

shadders

Well-known member
Nov 19, 2009
212
130
18,970
Hi
Thanks for your response. I’m ashamed to say that after over 30+ years of just plugging speakers into Amps and hoping for the best I’m only now starting to look into the technical side of things so I’m not quite sure what some of your response means?
I am looking at running all speakers at the one time (x8)
1. What is SPL and why does it matter?
Thanks
Hi,
SPL is sound pressure level, essentially how loud the sound is.

For the amplifier you have, it is a stereo amplifier, it can only run 2 speakers at one time.

To run 8 speakers, 4 per channel, you would have to series 2 speakers, and then parallel the series connected speakers. If the speakers are 8ohms, then each will have 10watts output per speaker per channel. Then the issue is the sensitivity of each speaker type being different will result in different volumes from the different speakers.

There will be no way to get round the speaker volume difference issue, so, i would not attempt it.

Some amplifiers have two outputs, such as A and B, but this still means you are sharing the output of the amplifier between two sets of speakers, and any low impedance dips in the speakers, could cause the amplifier to fail.

Regards,
Shadders.
 
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Sep 22, 2021
5
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Hi,
SPL is sound pressure level, essentially how loud the sound is.

For the amplifier you have, it is a stereo amplifier, it can only run 2 speakers at one time.

To run 8 speakers, 4 per channel, you would have to series 2 speakers, and then parallel the series connected speakers. If the speakers are 8ohms, then each will have 10watts output per speaker per channel. Then the issue is the sensitivity of each speaker type being different will result in different volumes from the different speakers.

There will be no way to get round the speaker volume difference issue, so, i would not attempt it.

Some amplifiers have two outputs, such as A and B, but this still means you are sharing the output of the amplifier between two sets of speakers, and any low impedance dips in the speakers, could cause the amplifier to fail.

Regards,
Shadders.
I currently have the x8 speakers running into the splitter that then goes into the amp. Which works but I’m wondering if I get a more powerful rack type amp would this enable me to get the most out of the speakers? I want to use them in a venue setting not just a home setting.
 

shadders

Well-known member
Nov 19, 2009
212
130
18,970
I currently have the x8 speakers running into the splitter that then goes into the amp. Which works but I’m wondering if I get a more powerful rack type amp would this enable me to get the most out of the speakers? I want to use them in a venue setting not just a home setting.
Hi,
OK, so the splitter only allows 2 speakers to be used at the same time ?

Do you have the model of the splitter or any specifications ?

Regards,
Shadders.
 

RoA

Well-known member
Feb 11, 2021
295
149
570
Jamo D265 ... the first speakers I owned when I was young. Memories of a distant past.

You use 4 of these and another 4 large boxes all at the same time (in the same room)?!

If so, sound quality probably doesn't feature highly but you may benefit from a multi channel power amplifier from the likes of Monacor, Behringer, Crown etc.

It'll go even louder if the speakers can take it.
 
Last edited:
Sep 22, 2021
5
0
20
Jamo D265 ... the first speakers I owned when I was young. Memories of a distant past.

You use 4 of these and another 4 large boxes all at the same time (in the same room)?!

If so, sound quality probably doesn't feature highly but you may benefit from a multi channel power amplifier from the likes of Monacor, Behringer, Crown etc.

It'll go even louder if the speakers can take it.
Thanks yes I use them in the same room, not too loud and they sound fine. But I’m looking to make a small stack sound system and use them in small venues but louder.
I don’t want to blow my speakers or current amp so wondering if I need a better speaker splitter (or desk) and rack style power amp.
It sounds like the Rotec 100w will also impede the Jamos full potential also and as you can pick up Jamos pretty cheap I’m wondering if I replace the Rotec with Jamos and in effect have a wall of Jamos all with same spec so I’m getting the best out of what I have.
I don’t have the cash to build a sound system stack from scratch so I’m using what I have and can afford.
Thanks
 

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