Amplifier advice wanted

[IA76]

Hi

 

My current audio experience is with 100v systems but a friend has gone and purchased 10 x 6 ohm speakers (Dali Zensor 1) for use in a community building. The speakers were actually supplied by an AV shop when they asked for speakers for a PA system.

 

Which amplifier would you suggest and how would the speakers be wired up?

 

The speaker spec is http://www.dali-uk.co.uk/en-GB/Loudspeakers/ZENSOR-1.aspx

 

 

Thanks for your help

[MarkPAman]

If you wire 5 pairs in series, and then each set of 5 in parallel, you'll end up (theoretically) with 2.4 ohms which some amps can cope with.

 

If you wire two sets of 5 in series & parallel them you'll end up with 15 ohms.

 

Any other method will not give you the same volume from each speaker. Though that may to matter to you.

 

An amp that can give you 250 - 1000W at those impedances would match the figures you give for the speakers.

 

Or, you could fit a 100V line transformer to each speaker….

 

Edited for clarity, I hope.

[Owain]

Any series/parallel arrangement is vulnerable to a broken connection taking out multiple speakers and being difficult to fault-find.

 

I'd take the speakers back for a refund on the grounds of not suitable for the purpose.

 

 

[IA76]

Any series/parallel arrangement is vulnerable to a broken connection taking out multiple speakers and being difficult to fault-find.

 

I'd take the speakers back for a refund on the grounds of not suitable for the purpose.

 

 

 

 

The speakers were sold to them by Richer Sounds and the problem is that they have already been fitted to the walls and they have had them for a few months. I think the 100v transformer may be the only option left.Thanks for the help.

[Lamplighter]

You could wire 4 speakers in series/parallel to each channel of an amplifier running double mono. This would need an amplifier of 200 watts per channel at 8 ohms. The remaining pair could be run off a separate amplifier, ( 50watts per channel 8 ohms) slaved off the first amplifier. It would probably be cheaper than 10 decent transformers.

Brian

[Owain]

It would be helpful to know the intended use of this system - are all these speakers in 1 room for speech and foreground music (and how big a room), or background music, or in different rooms for background music and paging, etc.

[IA76]

The speakers are spread over different rooms with no one room having more than 2 speakers. The main room has a mic setup where spoken classes/lectures are delivered and the speakers are fitted around the building so the spoken audio can be heard in all rooms. None of the rooms are very big as it is a converted house.

[GaryNattrass]

I think I would be looking at zoning the speakers and therefore possibly having separate amplifiers in each room, this will also allow levels to be controlled on a room by room basis and each room fed with a line level signal rather than running huge amounts of speaker wire. As the rooms are small they don't need a huge amplifier and having something local to each room would also allow future flexibility if not all rooms are to be used for the same function.

 

Another alternative is to zone the amplifiers and control them from a central area but still with the ability to switch sources so the different rooms can be fed with a variety of sources.

 

You can get four channel amplifiers so it may be that you can have a four channel amp to feed four of the rooms in mono and a stereo amp to feed the main room in stereo.

 

For example I have an InterM QD 4480 amp that would be suitable to feed the four rooms, a stereo amp of similar size could be then added to feed the two speakers in the main lecture room, this will also allow them to be a lower level to prevent feedback etc..

A small mixer such as a behringer 502 could then be used to feed the main stereo amp from the outputs with the tape out being used for the room amplifiers.

 

A larger system could use a mixer with an aux output or group out to feed different zones or even a bespoke zoning mixer like the ones made by cloud etc.

 

Lots of options but as I don't know your budget more detail is required.

[Owain]

I'd go 100V amp, speakers tapped at 5 watt so a 60 watt amp would suffice; if you need more in the larger rooms drop the smaller room speakers down to 3 watt or so or use a separate amp for the meeting room to allow for local control and music use as well.

 

Attenuators in each room to allow individual volume control if desired, or rotary switch on the transformer taps. Run a second cable along with the speaker wire in case volume restoration relays for announcement override are desired later. If volume control for a pair of rooms is acceptable then speakers can be paired to a 4ohm tapping on the transformer.

 

"community building" and "richer sounds" suggests budget is limited.

 

 

[djmatthill]

How About one of these in each room.

 

amp

This would run 2 speakers off the above

 

or

 

one of these if balanced imputs are required - You can power 4 speakers off this one

 

amp 2

 

Just a thought ?

 

 

Matt