Extracting hdmi audo and amplifying signal for 10 speakers

[dtm0211]

Hi Guys,
New to this great forum!

I have a set of ten old style bosch lhm0606 9w ceiling speakers with 6,3 and 1.5 watt choices (just a plus and minus spade terminal) that i would like to power by a new smart tv that im buying. The new tv only has hdmi, hdmi optic and usb ports.

Would you guys recommend some form of audio extractor and amplifier so that i can power the speakers?
Surely the audio extractor alone is not enough power for the speakers?

Many thanks
dtm0211

 

[TLS Guy]

Hi Guys,
New to this great forum!

I have a set of ten old style bosch lhm0606 9w ceiling speakers with 6,3 and 1.5 watt choices (just a plus and minus spade terminal) that i would like to power by a new smart tv that im buying. The new tv only has hdmi, hdmi optic and usb ports.

Would you guys recommend some form of audio extractor and amplifier so that i can power the speakers?
Surely the audio extractor alone is not enough power for the speakers?

Many thanks
dtm0211

It sounds as if those speakers are 70 volt PA speakers, that require a 70 volt PA amp. Setting those up is totally different to a usual domestic installation.

You will not be able to use stereo, only mono. So you would need to use the optical out, and get an optical RCA converter, and then couple the channels.

Then you need to set the total watt tapings of ALL the speakers, that is the SUM of the tapings, to match the total power of the amp as closely as possible.
This is how you balance the impedance of the speaker system to the impedance of the 70 volt amp. If you selected different watt settings for the speakers,, speakers with the lower watt setting will play quieter than the ones with the higher watt settings.

Honestly that is a pretty useless arrangement to listen to the audio from a TV.

Those speakers were installed either by an owner, or more likely a dumb builder, who can not tell a domestic residence from a shopping mall.

 

[Eppie]

I found the same information as TLS Guy. Those are not residential but commercial speakers intended for retail outlets. I think you can go up to a 100V line amp to drive them but if you don't have the amp installed already you would need to contact a commercial supplier of retail sound systems to get the amp and use an optical out to RCA converter as mentioned to connect to the TV.

To be honest, those are *cheap* speakers that sell for $25 a piece. That's why stores use them. They will likely sound no better than the speakers built in to the TV. You didn't mention if this is a retail or residential setting. If retail, the advice above applies. If residential, those speakers should be removed and you should look into proper residential equipment.

 

[TLS Guy]

I found the same information as TLS Guy. Those are not residential but commercial speakers intended for retail outlets. I think you can go up to a 100V line amp to drive them but if you don't have the amp installed already you would need to contact a commercial supplier of retail sound systems to get the amp and use an optical out to RCA converter as mentioned to connect to the TV.

To be honest, those are *cheap* speakers that sell for $25 a piece. That's why stores use them. They will likely sound no better than the speakers built in to the TV. You didn't mention if this is a retail or residential setting. If retail, the advice above applies. If residential, those speakers should be removed and you should look into proper residential equipment.

The problem is that the system will almost certainly have to be rewired, as the speakers are most likely daisy chained with bell wire. The whole point of the pro 70 volt or 100 volt (70 volt is much more common) is to be able to string large numbers of speakers together with very cheap bell wire. There is a transformer at each speaker, and the amp to speakers is the high impedance side. So the current in the wiring is very low, so you can use the cheapest thin gauge bell wire, without problems.

These systems are for PA messaging and background music only. Installed in the right application this system has served s well for about a hundred years now.

In my opinion a home is not the right application, unless you must have background music. I would bet this was done by a pro installer on the cheap, because the builder thought it would add value. Experience shows that this sort nonsense, decreases home value.

My view is that it will be far more trouble than it is worth, to make anything useful out of that system.

 

[Eppie]

The problem is that the system will almost certainly have to be rewired, as the speakers are most likely daisy chained with bell wire. The whole point of the pro 70 volt or 100 volt (70 volt is much more common) is to be able to string large numbers of speakers together with very cheap bell wire. There is a transformer at each speaker, and the amp to speakers is the high impedance side. So the current in the wiring is very low, so you can use the cheapest thin gauge bell wire, without problems.

These systems are for PA messaging and background music only. Installed in the right application this system has served s well for about a hundred years now.

In my opinion a home is not the right application, unless you must have background music. I would bet this was done by a pro installer on the cheap, because the builder thought it would add value. Experience shows that this sort nonsense, decreases home value.

My view is that it will be far more trouble than it is worth, to make anything useful out of that system.

The op hasn't given us enough information really. Only said that he has 10 ceiling speakers. They could have been a garage sale find and not even installed. Hopefully you've saved him from wasting the effort either way.

 

[BMXTRIX]

While already explained as a pretty bad solution in a home, it is important to know that it is fairly easy to get these setup and taken care of.

First, some specs are right here for them, and they are indeed rated as 70v speakers...

https://resources-boschsecurity-cdn.azureedge.net/public/documents/LHM0606_00_US_Data_sheet_enUS_1945383179.pdf

From there, you need to KNOW how they are wired and setup. As mentioned, if they are not installed, they should not be. They are completely wrong. But, if they are wired, in series as they likely would be, then you just need an amp which can handle them. With a maximum of a 6 watt tap, the most 10 speakers would pull is 60 watts of power. This is nothing in the commercial world where a hotel may have 100+ speakers on a single run.

An amplifier like this will take a line level input and convert stereo to mono and deliver 200 watts of 70v available power.

Extron XPA 2001 amplifier (Used, 70V, power cable included) | eBay

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Something like this is decent, but needs a Extron power supply to go with it. It only gives 40 watts of power, so you would need to set the taps at 3 watts.

Extron MPA 401-70V Mini Power Amplifier, Power Adapter NOT INCLUDED | eBay

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power: https://www.ebay.com/itm/174759884762?hash=item28b08037da:g:NCoAAOSwVs1f4TBX

You do want to ensure that if you buy one of these amplifiers, then you get one which includes the phoenix connectors on the back of the unit for at least the output connection to the speakers. The 5-position connectors are readily available on eBay or elsewhere. I've gotta have about a hundred of them. They are easy enough to pick up.

Really though, while people have thrown out that these shouldn't be used, it would be best to get a lot more information about your setup and situation.

 

[dtm0211]

Thanks all for taking the time ill might go down the path of trying to operate them - very good information.

They are all installed and each speaker has its own set of wires brought back to a central location.
While i now know that they are not the best solution, im still going to try to power them - im not totally fussed about the sound quality.

I will try to get a70v - 100v amplifier for decent money and see how i go.
Again, thanks for the replies.

 

[Eppie]

Thanks all for taking the time ill might go down the path of trying to operate them - very good information.

They are all installed and each speaker has its own set of wires brought back to a central location.
While i now know that they are not the best solution, im still going to try to power them - im not totally fussed about the sound quality.

I will try to get a70v - 100v amplifier for decent money and see how i go.
Again, thanks for the replies.

The 100v rating I found was on a British site with a different version number of your speaker. If Bmxtrix says to use a 70v amp, go by his advice. He has direct experience with these systems.

 

[lovinthehd]

FWIW I could part with a Crest CM2208 easily enough as have never found a good use for it. It's 8ch capable, as well as 70V operation. It's got noisy fans so unless you have a separate room for such, wouldn't be a good fit for most.

 

[TLS Guy]

The 100v rating I found was on a British site with a different version number of your speaker. If Bmxtrix says to use a 70v amp, go by his advice. He has direct experience with these systems.

With that small number of speakers, I would use a 70 volt PA amp. You probably want to get an amp with a volume control, as you can not use speaker volume controls.

I would still cation you to consider if this is worth it. Ceiling speakers are just lousy for TV audio and VERY irritating.

 

[lovinthehd]

Overall I'd really like to know what the purpose/expectations of this system are. It doesn't sound like sound quality in any case....

 

[BMXTRIX]

People who haven't used 70v speakers need to understand that they do sound reasonably good. They are a industry standard in boardrooms around the nation. USA typically using 70v systems, Europe typically using 100v systems. So, it's pretty easy to know that in the USA, it will be 70v. Overseas, it could be 70v.

The speakers do not sound 'bad', and while in-ceiling speakers aren't ideal for watching TV, they are a solid choice for discrete music listening around the home, for non-critical situations. These aren't what you put in your 'music room'. They are what you have in the kitchen while you prepare your meal and want to stream over bluetooth to the home.

Yes, there are 70v volume controls. Of course there are! These systems are used in office spaces all over which have generic Mood Media or similar playback throughout the office, and people can control their individual spaces. I've used them in fairly high-end residential and hotel spaces to playback music in lobbies, outdoor amenities, rental offices, etc. with really nice source distribution options.

It's not as good as a proper 8-ohm system, and those speakers are pretty low-budget. But, if they are in place, then they are in place. The hard part now is knowing if volume controls are already in the different areas, or much else. The original poster has been a bit thin on the details. I'm expecting a "I'll look into things, thanks." type of response instead of a post that might show some photos of what he is dealing with or more details of what the specifics of the setup are.

@dtm0211 - It would go a long way to getting things really figured out if you really got into the details of the speakers, their location, and your setup.