Hello

[DiscoTex]

Hi

I've been into music and associated electronics for years.

I built my first disco unit at 14, from 2 old gramophones dropped into the rather pretty front from my parents' old piano. Kept on trestles over my bed.

It never went on the road, but was great practice for queuing the next tune.


Now the proud owner of an NEC A820E amplifier, running into Skytronic speakers and occasionally ProSound speakers, with SoundLab decks, and a Numark CD mixer.

Looking for advice on matching bigger amp and speakers, ie do the speakers need to bigger than the amp, or the other way round ???

Thanks
Andi

[Spectral Morn]

Welcome to AoS Andi

[walpurgis]

Hello Andi. Welcome to AOS.

If you want opinions on amp matching, why not start a thread in the Blank Canvas section and ask a few questions? I'm sure our members can help.

In any case, power matching is not too critical.

Feel free to join in with the chat here, there's plenty going on.


Enjoy the forum,
Geoff.

[Macca]

Hi Andi, welcome to the Forum

[Barry]

Welcome to AoS Andi,

All of your equipment is unfamiliar to me, but when it comes to amplifier power it is always better to have too much power than too little. If the amplifier is underpowered for the speaker there is a risk it will 'clip', and the high frequency harmonics of the clipped waveform can easily damage the tweeter.

What are your tastes in music?

Enjoy the Forum
Barry

[DiscoTex]

Welcome to AoS Andi,

All of your equipment is unfamiliar to me, but when it comes to amplifier power it is always better to have too much power than too little. If the amplifier is underpowered for the speaker there is a risk it will 'clip', and the high frequency harmonics of the clipped waveform can easily damage the tweeter.

What are your tastes in music?

Enjoy the Forum
Barry

So running the NEC amp with 4x80w channels into 2x100w Skytronics and 2x150wrms/300wpeak is not a good idea... I guess it's back to eBay to get something with more beef, and keep the "rather nice" NEC amp for home use. It is powerful, never goes beyond 2 out of 10 in the house apart from the 10 second test when I got to 8/10 and scared the cat to the other end of the street, ha ha.

I need to get a suitable combination within a month for a room that takes 250. What total wattage would you recommend?

Tastes ? I have 400 7" singles that I take out, 25% Northern Soul, 50% Groove/70s Disco/Funk, and 25% Reggea/Ska, plus loads of random stuff picked up over the years that sits gathering dust.

[Barry]

250 bodies will absorb a lot of sound, but it also depends on the size of the room and how loud you want the level to be.

[Barry]

Can you let me know the model number of your Skytronic speakers? There are several models - I need to know the sensitivity of your speakers to be able to help you with your query.

[DiscoTex]

Barry
Skytronics are labeled
100.051, power 100w impedance 6ohms

ProSound are labeled
300 prog 150 rms
PS10 version II 8ohm

Thanks
Andi

[DiscoTex]

The room capacity is 250, but they are limiting ticket sales to 200 to give people room to dance, it's a typical WMC layout. The crowd we are aiming at likes it loud !

[Barry]

Thanks Andi,

What I really need to know is the sensitivity of your Skytronics and Prosound speakers. I can't find any information on them on the web.

The sensitivity is usually quoted in dB/W at say 1metre, and gives a measure of the loudness of the speakers for a given power at their input.

[DiscoTex]

Sorry,but that's all that's said on the labels for the Skytronic.

The Prosound are model N92FN
8ohm,
frequency response 60Hz - 18kHz
Sensitivity 94dB

I've just ordered a QTX SPL1000 1000w Stereo Amplifier with Bluetooth, USB, SD & FM Player

Frequency response: 20Hz - 20kHz
THD: <0.5%
S/N ratio: 95dB
Channel crosstalk: >82dB (@ 1kHz)
Input impedance: >10k Ohms
Power max.: 1000W

So this should be more robust for lugging about, and won't spoil the speakers with "clipping", but now I am concerned that I might turn it up too much and blow them, so might need to get bigger speakers after all...

[Barry]

I've had a look at the Prosound N92FN speakers and they have a quoted sensitivity of 94dB/W. The maximum power they can handle is 150W.

150W is 22dBW, so the speakers when fed with the maximum power of 150W will produce a sound pressure level of 94 + 22 = 116dB. This is very loud, though not untypical in nightclubs.

To give you some idea of how loud it is: 100dB is the loudnesss level of a pneumatic drill heard at a distance of 12'. 110dB is the loudness level produced by chainsaw, or a jet plane taking off. Ear defenders are used by personnel working in these highly noisy environments.

Although the sound pressure level in the venue will not be a constant level of 115dB, remember permanent hearing damage will be caused if one is subjected to such loudness levels for more than 15 minutes.

I suggest you enqire as to the permitted levels allowed by your local council, and use a sound level meter to check they are not exceeded.

[DiscoTex]

Barry

That's great news as far as making sure that it's not too quiet; do you recommend using the 80w amp (which could be 40w/channel, not sure) and making sure it does not "clip", or the 500w/channel amp and keeping the volume down?

Andi

[Macca]

Use the more powerful amp and keep a check on the volume. You can tell if it is loud enough or too loud, trust your judgement.

There is less chance of the 1000w amp clipping and less chance of it packing in under sustained load. I'd test the whole system at gig level first for a good hour or so just to make sure. Don't leave it to the soundcheck. Make sure the new amp is fault free and robust way before hand. But have the other amp as a spare with you too. Ideally have a spare for everything.

[DiscoTex]

I just saw the same amp bundled with 2 x 150w speakers! I asked them why they were selling a 1000w amp with these, this is their response

Although the amp is 1000W that is a maximum combined power for both of the channels. each channel is in fact 150w per side which is matched perfectly to the speakers.

That sounds to me like 300w total, surely a case of misrepresentation ?

[struth]

the smaller value will be the rms(root mean sq) the other if its genuine and i doubt it could be maybe a peak to peak or something

[walpurgis]

Although the amp is 1000W that is a maximum combined power for both of the channels. each channel is in fact 150w per side which is matched perfectly to the speakers.

That's probably correct. The claimed 1000 watt output is likely the (useless) PMPO rating.

I looked at a few reviews. It seems to have reliabilty issues and noisy fans. Still, at £89.95 you won't get top quality.