Whole Home Audio in Garage

[MTguy]

Greetings all! I have a legrand OnQ Lyriq whole home audio system that I wired a keypad to in my garage. Basically, the wall keypad is a 20w/channel amplifier for sources that I can remotely control. The plan was to use that to power 2x 5.25" in ceiling monoprice speakers (wire is already ran but speakers not installed yet). I'm about to close up my walls and I'm concerned it's not going to put out enough sound to make me happy. My two ideas would be to either finish that system as was planned and then just run extra wires now so I can put in a full stereo in there in the future OR I could find an amplifier that will take that 20 watts per channel and amplify it again and also split it to more speakers. I'm not 100% sure how I would do that without spending a small fortune though. I do have quite a bit of extra speaker wire I could use so that is cheap enough. FYI, the garage is roughly 28x36, 870.5 sq ft, and 11.5' high ceilings.

What do you guys think? Am I missing an alternative? Does anyone have concerns with using speakers in the ceiling of an attached garage as it relates to fire/insurance claims? Help a brother out!

Here are a few links that might help:
My build threadhttp://www.garagejournal.com/forum/showthread.php?t=283280
Lyriq system like mine http://www.smarthome.com/onq-legrand-au5514-wh-lyriq-multi-source-4-zone-kit-in-studio-design.html

 

[RunninOnEmpty]

Well, replacing the amp or adding another amp is definitely an option. If you add another amp, it doesn't take 20 watts in - 20 watts is with a speaker load of 8 or 4 ohms or whatever your amp is rated at. Sometimes whole-house systems use higher impedance than that. But an amplifier input can be as high as 50k ohms or more, and the power formula P=V²/Z (power = voltage squared divided by impedance (R or resistance in a resistive load)). You would need to make sure that your 20W amp is outputting the correct VOLTAGE for the input of whatever new amp but you could fix that with a voltage divider consisting of literally under $1 of resistors and you can use cheap and small 1/4 watt resistors for this. If you use a second amp, you will not even have 1/10 a watt of power going from the keypad amp to the second amp. On the input side of the amp what matters is voltage and power is always going to be extremely low. Using 2 amplifiers like this would essentially mean you're using the first amp as a pre-amp for volume control only.

You could also focus on having more efficient speakers which you could do via different ones (and larger speakers are almost always more efficient - most people misunderstand and think you actually need more power with larger speakers, but most of the time you don't need as much). Your speakers are rated 87dB 1W/1m, and these are rated 90. Simply swapping out your current speakers for the ones I just linked would increase your sound as if you had doubled your amplifier output power. 3 decibels. But even 3 decibels, while noticeable, is not a ton. If you're really, really dissatisfied, you should be looking to add at least 6 decibels of output. If you have a receiver or something that displays power in decibels (typically will be a negative number), try listening to it at some level, then increasing it 3 decibels. See if that increase is going to be enough for you.

You could also add MORE speakers, but your amp is rated for 8 ohms, so you'd need to go from 2 speakers to 8 speakers (if you stayed with 8 ohms) which gets a little out of hand. 4 speakers would only be able to give you 4 or 16 ohms, neither ideal. If you were to buy 3 more pairs of your current speaker and hook up all 8 speakers, you would gain 6dB of output. Each time you double the amount of speakers while keeping impedance the same, you gain 3dB of sensitivity.

 

[MTguy]

Thanks. I never even considered that difference in voltage for the input. I was considering using speaker to line converters originally if I couldn't find an amp that would work.

I was already thinking of getting bigger speakers anyways. They generally sound better to me. I will end up taking a bit of a loss on the small speakers, but maybe I can list them for sale locally.

 

[jonjon1]

I have a whole house system and it goes into the garage also, BUT I don't use it out there, I use a small integrated amplifier and a pair of bookshelf speakers, I normally just hook in my cell phone and play from there...

In my garage I have a dayton apa150 amp and a pair of ascend acoustic cbm170s, it sounds awesome...

Another option for you if you don't want to mess with something separate and want it to be integrated with your whole house system is to split the input that comes out of you receiver before the module, run a pair of rica cables out to your garage and then plug it into an integrated amp, you could do this pretty cheap.
You can get a dayton amp and that will be plenty loud enough to run any set of speakers. I like the ascend stuff because its nothing flashy, them cbm170s sound amazing for the money, but you can get even cheaper bookshelf, or in ceilings, I have yamaha in ceilings through out my house they sound good, jam also makes a nice set...

One more option is to run a speaker to line level converter to another amplifier, but I think running a set of ca's would be a better option. Also a wireless rica converter would work too, if you are close enough, they are affordable now and work pretty good...

many many options...

 

[RunninOnEmpty]

I've updated my post and the end of the second paragraph now has a suggestion to see if you might be satisfied just by swapping speakers alone. I'll repeat it here to make it easier for you to read in context.

If you have audio in another room, in your car or wherever which tells you the gain in decibels, which will often be a negative number, try listening to something at a volume which is sort of low to you but audible. Then increase the gain/volume (they aren't the same thing but in this case both terms apply) by 3dB per the display. Go back and forth between the 2 volumes. Think about it and figure out if the increase of 3dB would be enough for you. If it is, all you need to do is swap speakers. If it isn't, you will need to increase your amplification and/or add more speakers.

Edit: Oh, and using speaker-to-line converters between two amps, or using an amp that has a "line level input" (much more common on car audio amps than home audio, though, other than subwoofers) would be fine. Will cost more than using a couple of resistors per channel to make a voltage divider, but will also be plug-and-play and won't require cutting cables to solder (ideally, anyway.. I guess you could crimp if you're careful with it) the resistors to. The speaker-to-line converters (in cars often called LOC for "line out converter") are pretty much just voltage dividers. Some of them are active meaning they use transistors (or perhaps an op amp) to buffer the signal, but that's usually not necessary.

 

[Ray916MN]

Unless you only work at one end of the garage, I'd wire for speakers at all 4 corners . With 2 speakers, the problem is going to be with the volume set for working close to the speakers, it is going to be too low at the other end of the garage, or when you set it for the far end it is going to be too loud near the speakers.

 

[MTguy]

Thanks guys. The system is not fully up and running yet even though it is 95% done for the rest of the house (need to finish the audio/media closet) so I can't test it just yet. The sound travels over cat5 so I don't know if I can split that to RCA's. Right now, I'm leaning toward going with larger speakers anyways (probably in wall rather than ceiling) and just finishing up the existing system. I'd then just run about 4 pairs of speaker wire to the attic for future use. I need to get the sheetrock up in the garage so I can get my heater hung.

 

[RunninOnEmpty]

Unless you only work at one end of the garage, I'd wire for speakers at all 4 corners . With 2 speakers, the problem is going to be with the volume set for working close to the speakers, it is going to be too low at the other end of the garage, or when you set it for the far end it is going to be too loud near the speakers.

Increasing the number of speakers is not a bad idea, but in this case, his amp is rated at 8 ohms (I looked it up) and his speakers are 8 ohms. To add 2 more speakers, he'd either have to run them in series for 16 ohms which would add 3dB for the extra speaker but also subtract 3dB because the impedance is halved. Or he could run them in parallel for 4 ohms, but since his amp is rated for 8, it's probably going to distort, go into protect (shut down), or blow up.

He'd need to use a different amplifier rated for 4 ohms, or use 4 (or 16) ohm speakers in order to have a final impedance of 8 ohms to use with his current one.

Given the size of his space, I think that 4 speakers is definitely a good idea if he can make the impedance work.

 

[Ray916MN]

....

He'd need to use a different amplifier rated for 4 ohms, or use 4 (or 16) ohm speakers in order to have a final impedance of 8 ohms to use with his current one.

Given the size of his space, I think that 4 speakers is definitely a good idea if he can make the impedance work.

Can always run in parallel and put a resistor in to get the impedance up to an acceptable level. The real question is what does the impedance curve of the speakers look like, since 8 ohms is a nominal impedance. If it bottoms at say, 6 ohms it is possible that even in parallel his amp could handle the lowered impedance without blowing up and he could get the benefit of higher output from the amp at the lowered impedance

Either way, with that much square footage, I'd plan for 4 speakers. I run 5.3 in my shop and when I'm listening to music in stereo mode, versus when I'm watching TV and the rear channels are limited to surround fill the lack of even sound distribution is very noticeable.

 

[RunninOnEmpty]

Can always run in parallel and put a resistor in to get the impedance up to an acceptable level. The real question is what does the impedance curve of the speakers look like, since 8 ohms is a nominal impedance. If it bottoms at say, 6 ohms it is possible that even in parallel his amp could handle the lowered impedance without blowing up along with the benefit of higher output.

Yes, it's possible that his speakers do have a higher minimum impedance than most and that his amp will work, but I don't think it's likely. If his amp were rated for 6 ohms and he had 8 ohm speakers that he wanted to put in parallel, I think it would be more likely, but there's a significant difference between 8 and 4. Your understanding about the nominal impedance is right, though.

I would not recommend a resistor because it would need to be a 10W+ power resistor and it would lower the sensitivity by 3dB which is significant given the scenario.

I think we've already convinced him to consider different speakers, so I think he might be okay if he buys 4 4-ohm speakers, preferably with higher sensitivity than the current ones. Though watch out on sensitivity ratings with 4-ohm speakers. They can be at 1W/1m or 2.83V/1m. 2.83 volts is what you need for 1 watt at 8 ohms, but it's 2 watts at 4 ohms. (There are reasons to use 2.83v rather than 1 watt for sensitivity - it's not just marketing BS - it's much more helpful when designing crossovers. But it can be confusing.)

The previous comment about bypassing the in-wall amp and using a normal integrated amp or receiver is also fine if the signal into the in-wall unit is analog and easily tapped (or if you can tap it separately at the source). You would only be able to control it from that unit, rather than the in-wall unit (or centrally if the system supports that), but it would still allow him to use the same source unit and it might be good enough for him. If you get a used IA or receiver, this is probably the cheapest option. You could probably find a 70s-90s integrated amp in the $0-20 range without a ton of looking around.

 

[Ray916MN]

Kind of interesting. I haven't looked at this stuff in a long time. I come from the era when amplifiers were pretty much always output rated for 8 and 4 ohm loads and the particularly high output amps were spec'ed for 2 ohms.

A search for the specs on amp comes back with this http://www.legrand.us/onq/audio-video/volume-control/studio-design/au5010-wh.aspx#spec :

Output Impedance: 8 Ohms per channel (1 pair of speakers)
Speaker Impedance Load: Load: 6 Ohm max

Manufacturer spec error or are somehow digital class D amps vulnerable to high impedance?

 

[RunninOnEmpty]

Class D amps are much more sensitive to load impedance than A/AB/B/etc. They use an output filter tuned specifically for that circuit and in most class D technologies the speaker itself affects that filter so using different impedance speakers can actually change the output filter of the amp itself. You can find them that do work down to lower impedance like 2 or 1 ohm but those are mostly just car audio.

I like Philips/Hypex UcD for Class D but it's not common.

 

[MTguy]

Wow, you guys know your stuff. Would tapping the line on the speaker side of the amp/wall control with speaker to line (rca) adapters ->then using a 120v amp to power multiple speakers-> allow me to control everything from the wall unit? Even if i can find 4 or 16 ohm speakers I worry that 20 watts won't be sufficient.

 

[RunninOnEmpty]

Yeah, that would be fine.

 

[Ray916MN]

Yeah, that would be fine.

Don't you need a line out converter to make this type of arrangement work?

 

[Ray916MN]

Are you going to have a laptop in the garage? It looks like you could access and control your home media network through the laptop and plug the laptop audio out into the amp or receiver and just skip the expense of the wall control amp.

 

[Troutsqueezer]

I'm not clear on why you think 20 watts is not enough. It is quite loud, relatively speaking. The ear is sensitive to changes in frequency but not to changes in amplitude. You may or may not hear a 3dB difference in sound level. An increase in 3dB corresponds to a doubling of power so you need a forty watt system to achieve that. Doubling the power in any amp calls for an increase in amplifier component cost almost exponentially.

Consider that amplifiers are generally designed to deliver no more than 12% of rated power continously. More than that and they will overheat and blow up if not protected. This is why when testing rated power on a test bench, you hold the amp at rated power just long enough to take the distortion measurement. In real life, the average level of music falls around 12 dB below the peak levels in that music (depending on the dynamic range of the recording). So even if you had a 100 Watt amp, the Wattage levels you are listening to average way way below 100 Watts. There's more to it than what I am describing here but maybe you get the point.

BTW, input impedance on typical amplifiers, both home and car audio is around 10k ohms give or take. Much higher than that will cause signal reflection and noise interference. Standard consumer line level input is .316V RMS.

 

[RunninOnEmpty]

Don't you need a line out converter to make this type of arrangement work?

Sorry for the late response but he mentioned that. He called it a "speaker to line adapter" which is the same thing as a "line-out converter."

 

[MTguy]

Thanks again guys. Right now the plan is to order some 8" speakers, mount them centrally in the garage walls, and use the wall control for power by itself. I'm also going to run wire for 2 more pairs of speakers to the attic for a future "shop stereo" if I decide I need it. K.I.S.S. is probably best for me.

I probably will end up with a laptop or computer in the garage and it is wired with 2 cat6 drops as well as 4 lines ran to the attic for future use (probably POE cameras). I have a pretty big media server in the house that I can tie into for music and TV if I so decide but I've already got satellite TV out there so that will probably be enough.

 

[MTguy]

Decided on some 8" in wall speakers from Monoprice and got them ordered when they actually have a sale. I went with these 8" ones.http://www.monoprice.com/Product?c_id=108&cp_id=10837&cs_id=1083703&p_id=4101&seq=1&format=2
I guess I'll sell my 5.25" ceiling ones locally. I'm going to put them about midway in the garage for overall background noise.