Ceiling speakers 6ohm or 8ohm to match or Db's?

Homoaner

Novice Member
Joined
Dec 15, 2016
Messages
49
Reaction score
2
Points
37
Age
59
Location
Gulf of Mexico
Hi All,

Question:

I am buying in ceiling speakers to create my 5.1, albeit a 7.2 reciever Sony stdn1060. The L/R/C are PSB Series 5t's with specs of 92db @ 1/1m ~ 6 ohm rated 125 to 250 watts. The sony amp is said to run 165 using 6ohm speaks and 100 using 8ohm's "So they state.."

As I search for the ceilings, I am finding mostly 8ohm two ways. I have found one set of 6 ohm 3 ways however the rating is 89db @ 1/1m. From the reading I am doing, it seems that the db difference is only 3db's however that means the amp needs to feed those roughly 20% more wattage to get them to drive like the PSB's at 92db..

I do not want to have to crank those fronts L/R/C to get the ceilings to "come alive" just 'chasing my tail'.
I do not want the amp to 'protective shut down if they are the only 8 ohm's in the system...However my Subwoofer at the moment is only an 8ohm 80 watter... which being active should not be any draw persey'.
(From what "I think I understand")

I guess I am asking about the 8ohm's coupled with the 6ohm and un matched 8 ohm's Vs. 92db vs 89db rating at 1k@1meter ratings.
 
Rating an amp at 6 ohms is simply a way to inflate the apparent power. There is no such thing as an 6 ohms amp or an 8 ohm amps, there are only amps whose power is rated at a given impedance. The industry and legal standard is to rate power at 8 ohms so that all amps can be fairly compared.

As to the rated Sensitivity of a speakers, that is nice for comparing speakers, but means little in actual use. First the Sensitivity rating is usually at 1w at a distance of 1 meter. Likely you are going to be a bit father than 1 meter from the speakers.

Next, all modern AV Receivers have a Calibration/Setup program. This Setup program will balance all the channnels so they are the same volume at the prime seating locations, which is the location where the Microphone is placed for the Setup Test and Calibration.

Next, there is only a 4 db difference in the speakers. That would be a just noticeable difference; slight but noticeable. It is not going to be hard to balance those speakers.

Also, your Subwoofer - 8 ohm 80 watt??? Is this an Active Sub, that is, does it have its own amps built in? Because you need an Active Sub to use with any decent AV Receiver. It is typically only very low end systems that use a passive Sub.These are typically called HTIB - Home Theater in a Box system, and you are well above this.

Instead of thinking in terms of ohms, think in term of Current, and higher Current translates to more heat, and more heat translates to a higher likelihood of you amp shutting down. From this perspective 8 ohms is the preferred load because it draws the least Current and therefore generates the least heat. Though 6 ohms speakers are also fine. The problem is 4 ohm speakers, they typically draw considerably more Current and run noticeably hotter.

If you have a Sony amp, I think the Minimum load per channels is 6 ohms, so as long as you are NOT using 4 ohms speakers, you will be fine. 6 ohm and 8 ohms speakers, and speakers with a slightly different Sensitivity rating are going to be fine.


Steve/bluewizard
 
Also ceiling speakers are far from ideal for any speakers in a 5.1 system and certainly not for the front 3. If you want hidden speakers then I would look at in wall or on wall speakers for the fronts at least. When I have heard ceiling speakers as the front 3 the sound always seems detached from the action on the screen.
 
Thank you Steve for your input on this... So why does the amp rate at 8ohm @ 100 watt P/C and 6 ohm @ 165 watt P/C? IF that is just a benchmark to measure it...? Curious due to your response and the way it is sold...Why bother showing 8ohm is 100? Being a sales ploy... Does that mean that using 8 ohm leaves more "headroom" for the amp... Or will the user never get the wattage draw if using an 8 ohm speaker... Really falls back on the original question just digging down to get the difference between indeed using the 6's vs 8's as per your opinion the 3 db's are really going to be compensated via mic calibration... Amp is Sony 7.2 Channel Home Theater AV Receiver

I ask, as I have, and in previous, used 4Ω Audio Source's 'mix'- matched to those same PSB's 6Ω using a Pioneer and a Sony (threw both out due to could not figure out why they would shut down) Anyhow ... Those 4ohm same scenario here 2Ω ohm difference, using them as a "Zone B" as they call it now, would shut down those amps.. Hence me leaning towards those -3db difference. Matched and being 6ohm and letting the calibration deal with the db's albeit my head will be about 1 meter away from the ceilings when watching DTS etc... Thoughts?
 
Also ceiling speakers are far from ideal for any speakers in a 5.1 system and certainly not for the front 3. If you want hidden speakers then I would look at in wall or on wall speakers for the fronts at least. When I have heard ceiling speakers as the front 3 the sound always seems detached from the action on the screen.

Copy that here are the L/R's
PSB Imagine T (Black Ash) Floor-standing speaker at Crutchfield.com

The Center is the same match 5t PSB. Indeed In walls for the ceiling 3 ways Looking at 6Ω as in orig post.Thanks for the 'heads up'.
 
You are thinking about the power in the wrong way. An amp is a voltage device so at maximum power the voltage is the same. The power changes because of the impedance due to a lower impedance speaker drawing more current. Power is volts times current hence a lower impedance speaker can be used to give an inflated power rating.
The more current the amp is drawing the hotter it will get and at the extreme the amp can start to clip since it runs out of current from the power supply.
But more power does not always mean more volume since this relates to sensitivity so a 6 ohm speaker may give more power output but if the sensitivity is much lower than an 8 ohm speaker then it may still sound quieter.
I personally would pay little attention to the power ratings on AVRs as they often have little bearing on the real world power the amps put out anyway. You are better off looking at the size of the power supply as a more accurate guide of the power output from the AVR.
 
PSM1- So on that last explanation... The 8 ohm would be the last to draw enough to cause a clip or amp shut down... I'd have to blast those PSB's and prob blow the 8's if rated to low of allowable wattage then the 6's or PSB will take? So on that note...8ohm that are rated the same db sensitivity would be a better match, then worrying about the draw, better to have sensitivity and wattage maximum match...Right?
 
The difference in terms of 6 and 8 ohm speakers is small. Unless you have a massive room you are not going to be using anywhere near the maximum power of the amp in use so will not be near clipping etc. on either. You pick a speaker for what sounds best to you. The specifications you are looking at really mean nothing when picking a speaker as long as minimum values are met i.e. the impedance is a reasonable level (6 and 8 ohms are both fine) and the sensitivity is not too low (something in low 80s could stretch a lower powered amps).
 
Thanks for the help on this PSM1 That helps while shopping, the 6's are 25-50 bucks more and bit less sensitive as in db's -3.. Room is 14x14 where the T.V is and of course, I like my tunes to fill the rooms that spill off that room which is pretty good in size(s).
 

The latest video from AVForums

TV Buying Guide - Which TV Is Best For You?
Subscribe to our YouTube channel
Back
Top Bottom