Ceiling speakers - advice needed

[Corazones]

I am hoping to set up a system of ceiling speakers in the our home extension currently being built. I am not looking for bass response, just a good clean performance from about 50 or 80 to 16000Hz.

However, the more I look into this, the more I realise the extent of my ignorance - particularly regarding impedance matching, cross-overs, and adjustable power settings on the speakers. I was hoping to run two speaker wires throughout the extension, with junction boxes dropping down to wall switches in each room which connect that pair of speakers (in parallel). I also find a distinct lack of suitable mid-price amplifiers - I only need something modest, with CD and MP3 inputs.

Can anyone suggest a good basic book (or internet link) which would provide all this basic information? Or a recommended mail-order dealer who can talk me through it? Are my ideas at all practical?

Thanks for your help,
Alec.

 

[ChrisFrost]

Although what you want sounds simple enough, as you have found it does open up a can of worms. I install AV and multiroom for a living, so this kind of thing is bread & butter for me.

There are lots of ways to skin this cat. The big question is budget. Bodged DIY solutions will be cheap but compromised. There's also a good chance that the amp in such an install will die fairly quickly; say a couple of years. So buying cheap often means buying twice.

Solutions that will work well and keep on working will cost more. But they'll be "fit and forget", so worth it in the long run.

So, have you done some research and come up with a figure, or have you just stuck your finger in the air and plucked a number?

 

[Corazones]

Thanks, Chris. It's the can of worms that I need to understand!

I haven't set a budget because I aim low, and maybe learn from any mistakes and replace in due course anything that disappoints. I wasn't planning to keep the amplifier permanently on and control its output only via the speaker switching - I assume that running with no output would kill it quickly.

I read a very good posting in another forum, by a trade pro, clearly showing the difference between the back of cheap and expensive speakers - the crossover circuitry, overload protection and so on. The reason why I'm sold on ceiling speakers was that I lived in Spain for five years, and our villa was fitted with these (right down to the wall switch system I described). These all terminated crudely in a pair of speaker cables dangling from the plaster, but I figured it out and obtained very pleasing results. It won't be used a lot, and I don't expect perfection by any means, but I had in mind something like Penton or Bosch LHM 0606/10 speakers.

My immediate query concerns the wiring, as this has to go in at First Fix stage (presumably, these days, in conduit?). Is my basic idea sound, and if so do I have to do anything to match impedances when either one or two pairs of speakers may be in circuit at the same time?

Thanks again,
Alec.

 

[ChrisFrost]

I'm interested to know in which forum you saw the cheap versus good speaker posting. I've done a few of those.

BTW, those Penton and Bosch speakers, they're the cheap ultra basic ones. You do also realise that those Penton or Bosch speakers are 100 Volt line, right? That impacts on the way you wire the system and what's possible from it. With 100V line you don't need to worry about impedance matching. But there are some other things that you definitely do want to consider instead. So your idea of low-balling and then replacing as necessary is kind of scuppered if you want to go for something with better performance. If you set out on this path then your wiring will only ever work for 100V line systems.

I put 100V line systems in to leisure facilities, bars and pubs. The systems are designed for low-Fi background music. The amp's speaker output is mono. The wiring run is daisy-chained from one speaker to the next to the next. Introducing a volume control anywhere along the line means that all subsequent speakers down the line get quieter too. Is that really what you want?

There are multi-zone 100V Line systems. But the electronics at the head end is hardly discrete and very much of the "school of manual intervention" when it comes to operation.

I install 8 Ohm stereo multi-room audio systems in homes. They sound better and they are more flexible. They'll do the sort of things that you're looking for (stereo speakers, multiple zones etc). Have a quick look at my facebook page to see some of the multiroom stuff I've installed. Click on photos and scroll through.

For your sources, are you planning to switch and control them manually too i.e. put a CD in on shuffle and then go off somewhere in the house and listen?

 

[OwainDIYer]

do I have to do anything to match impedances when either one or two pairs of speakers may be in circuit at the same time?

That is the fundamental problem with conventional low-impedance loudspeakers; most amplifiers will drive 2 x 8 ohm speakers in parallel, which appears as 4 ohm to the amplifier, but more than 2 in parallel and most amps will overheat.

Even more complicated if you want separate volume controls in each room.

However, if these are the speakers you are considering
http://www.amazon.co.uk/Bosch-0606-100v-Ceiling-Loudspeakers/dp/B009L405IS
there is a simple answer:

100V loudspeaker distribution.

Each speaker has a transformer built-in to match it to the 100V loudspeaker line, as does the amplifier (usually, some amps drive the line directly) and you can simply connect as many speakers as you want in parallel up to the output of the amplifier in watts (allowing some spare capacity, usually 20% or so for music).

Each speaker transformer usually has tappings labelled in watts, and different speakers can have different settings, so you can have different volumes in each room.

If you want to adjust the speaker volume individually you use volume controls like this
http://www.amazon.co.uk/Wall-Mount-Volume-Control-50w-ATT-250/dp/B000WXKK00

Pros:
- speakers can have different volumes or be turned on or off without affecting other speakers
- thin cable can run over long distances without power loss
- one amp can power dozens of speakers

Cons:
- most 100V speakers are 'public address', not hi-fi
- unless 'music grade' transformers are used, bass response is poor regardless of how good the speakers are
- transformers at each speaker adds to the cost
- most 100V line amps are mono

Alternatives:

- distribute audio at line level and have separate amplifiers in each room
- use a speaker switching box which series/parallels the speakers to protect the amplifier, eg
http://www.richersounds.com/product/speaker-cables/qed/ss30/qed-ss30-3way-swch
or
http://www.qed-cable-shop.co.uk/Sys...qed-ss50-5-way-transmatch-speaker-switch.html

 

[OwainDIYer]

Introducing a volume control anywhere along the line means that all subsequent speakers down the line get quieter too.

If it does, you're wiring the volume controls (that I linked to above) incorrectly.

 

[Corazones]

Thanks to you all for your advice. Chris, I think the other forum I visited (and who never replied btw) was AVForums. Incidentally, I see you joined DIYnot in the same month as I did!

Thanks to both for explaining so clearly the differences between 100v and Hi-Fi systems. I'll take your advice and stick with the latter.

My priority now is just to link the rooms with speaker cable before they are rendered and plastered. I think I will terminate each room's cable separately at the amplifier position, inside a flush junction box, and then I can take my time deciding what to buy. I have also decided to wire only two rooms, and it is unlikely that even those will be on together.

One change I will have to make is because there's no room in the (vaulted) ceilings for flush speakers because they're stuffed full of insulation. I will therefore go for surface mounted speakers, which leaves me with a wider choice. I am just about to look at the Facebook page you mentioned, and I am sure this will give me some further inspiration!

Thanks again,
Alec.

 

[ChrisFrost]

One change I will have to make is because there's no room in the (vaulted) ceilings for flush speakers because they're stuffed full of insulation.

The walls and ceilings in most new builds and renovation jobs are. It's the same for us installing AV as it for electricians installing down lighters. We all have to remove insulation to make way.

 

[Corazones]

One change I will have to make is because there's no room in the (vaulted) ceilings for flush speakers because they're stuffed full of insulation.

The walls and ceilings in most new builds and renovation jobs are. It's the same for us installing AV as it for electricians installing down lighters. We all have to remove insulation to make way.

Aren't you supposed to fit lights or speakers inside a box if you do that? (A bit nervous with the building inspector snooping around!)

 

[ChrisFrost]

Well, its good practise to check the local requirement in case there are exceptions. But in general terms you need something to restore the fite rating of the ceiling if there's dwelling space above. This might be a fire tesistant box, or a hood/tophat or it may be that the lights have intumescent mayerial built in. The site I am on at the moment has just had about 30 down ligjters installed. These are the type with intumescent material built in. The mamufacturers requirements specify no insulation within a 15cm radius of the hole to allow for heat dissipation on these LEDs.

The four M&K inwall rear speakers U instalked all have fabric firehoods fitted. This would be the dame with inceiling speakers. BTW, a single decent inceiling fire hood will cosy as much as a pair of those 100v line speakers. Then again, you only "need" them is tjeres an bedroom or other living space above.

 

[Sam Gangee]

Typing in a hurry, Chris? It's not like you to leave 10 typos.

 

[ChrisFrost]

Walking round Sainsburys. How devoted to the forum is that! lol

 

[SimonH2]

But in general terms you need something to restore the fite rating of the ceiling if there's dwelling space above.

Also, you need to consider maintaining any moisture barrier.

If the ceiling is insulated then that suggests it's a cold surface above it (outside or attic). If you make a hole in the insulation then that's going to give you a cold spot on the ceiling (especially considering the space required around most downlighters if you fit them properly).
But the key thing is if you let moisture get through then it's going to cause condensation and all the problems that causes. So in those situations you need to ensure that the speaker maintains the moisture barrier.


Back to the OPs question.
If I were doing it then for just a couple of rooms I'd wire them back star fashion to one place (as the OP has suggested he's going to do), and probably wire them so they can be run in series - so (for example) 2x8Ω gives 16Ω across an 8Ω amp which isn't ideal but shouldn't be too bad for "lo fi" listening.
Past one or two rooms and I'd go with either 100V line or distribute at line level and use small amps for each room.

Either way, don't skimp on the cable - certainly don't copy another friend who (because he worked for BT had loads of phone cable) sires the speakers with phone cable which is completely inadequate.

A friend has a load of Sonos kit in his house, and rates it quite highly - but then he was owed a load of overtime that wasn't likely to get paid and I think they had some of his kit as surplus demo kits.

 

[ChrisFrost]

If the ceiling is insulated then that suggests it's a cold surface above it (outside or attic).

Your point about moisture barriers is valid. What I would clarify though is that inceiling insulation is now common between floors; or it certainly is on all the new build and major refurb' jobs where I have fitted inceiling speakers over the last few years. So it's not just to outside walls or the ceiling backing on to a roof or loft. Therefore moisture barriers are less relevant if it's inter-floor.

 

[Corazones]

Yes, the ceiling in question is a vaulted ceiling on a single-story extension, so there is 150mm of insulation there. Would it be OK to make a "X" cut in this and squeeze it partially to the sides?

Also, I did heed the warning about speaker cable as the runs are quite long, and went for 50 metres of good quality 2.5mm cables.

If I do find that I can use in-ceiling speakers, any suggestions as to the cheapest non-100v type which are acceptably good?