Church needs advice

Discussion in 'AV Receivers' started by Father John A, Dec 24, 2003.

  1. Father John A

    Father John A Stunt Coordinator

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    Hello all,

    We are currently using a STR-DE945 Sony. We are running a couple small Sony satellites for rears, two Boston A60's for the fronts and Phase Tech V6 for the center.

    Unfortunately I have read many negative reviews of this receiver. It makes me wonder if we might cause damage to the speakers? Is this a concern?

    If so, any recommendations for a replacement in the under $500 range? I know the STR-DA1ES can be had for less than that. Anything else?

    Thanks alot.
     
  2. Wayne Ernst

    Wayne Ernst Cinematographer

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    I doubt if the current Sony receiver is causing damage to the speakers - unless, you are pushing them to levels of distorting.

    Personally, if you are fixed on replacing the receiver, I'd look into something used in the range of $500. You could buy a lot "more" receiver that way. This is based on the assumption that you would need DTS, DD processing and maybe just ProLogic II features.

    Also, I just started a thread where the Marantz 5400 puts out power in the level that the manufacturer rates it - without overstating the specs like so many other manufacturers. The Marantz 5400 has a "list" price of $599. Of course, you could negotiate the price down a bit and get it for your desired price of $500.
     
  3. MikeTz

    MikeTz Stunt Coordinator

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    Father John:

    If you are using the system in a church (or other large room) the receiver may be reaching its power limits at relatively low volume. What size is the room in question?

    Merry Christmas

    MT
     
  4. Father John A

    Father John A Stunt Coordinator

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    Thanks both,

    The room is small, 14x22. Primarily used for movies.
     
  5. ChrisLazarko

    ChrisLazarko Supporting Actor

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    I would doubt you are causing any damage unless severely distorting the speakers. Other than that I don't see why you would have a problem.

    If you are set on replacing it, take a look at the Harman/Kardon AVR-225. It has alot of power for a reciever and will blow away the competitor for the price.
     
  6. MikeTz

    MikeTz Stunt Coordinator

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    Father John:

    The Sony is rated for 100 watts per channel into 5 speakers at 0.7% total harmonic distortion. Hang in there for a moment through this techno speak.

    Normally a distortion figure above 0.1% is audible to most of us. Meaningful power measurements are generally specified as XX watts per channel continuous from 20Hz to over 20kHz (the audible range, at least for teenagers) +/- xdB into 8 ohms with no more than 0.1% total harmonic distortion, all channels driven. This specification tells the perspective buyer that the amplifier will put out so many watts into an 8 ohm speaker load across the audible range with all the channels driven and no audible distortion.

    Still with me?

    Now the Sony has an interesting power specification. It says the amplifier will output 100w/ch in all 5 channels with 0.7% harmonic distortion. The amount of distortion is high and you would notice it if you ran the output to 100 watts in all 5 channels. Sony specifies the power this way to delude people into thinking they are buying a powerful amplifier. In reality the amplifier outputs much less power into 8 ohm speakers with less than 0.1% distortion.

    In a small room the receiver may be fine because movies almost never drive all 5 speakers at full power simultaneously. The surrounds are used for effects and ambiance. If you notice distortion on movies at moderate or reference levels there are several options.

    If the receiver processor section is acceptable (has Dolby Digital etc.) you could simply add an external 5 channel amp and use the receiver as a preamp/processor. You could invest in a new receiver or you could add a powered subwoofer to take some of the load off your receiver amplifier. If you already have a powered subwoofer then raise the crossover frequency between the sub and the speakers. This will put the burden on your subwoofer amp (and it can better handle this job) vice your receiver.

    An Outlaw 7100 on sale might be a good amplifier (or a used Anthem, or used Outlaw). Can the church buy a product named Outlaw? Receivers to consider might include the Denon AVR-1803, Yamaha RX-V640, the Outlaw 1050 (I know, the Outlaw again), or a used (or sale priced) Denon AVR-2803.

    MT
     
  7. Father John A

    Father John A Stunt Coordinator

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    Mike,

    Thanks for the lesson. You explained it very well.

    though I am far from an audiophile, I have been accustomed to descent sound since I was a young boy listening to my fathers B&O system in the 70's. While I do tend to listen loud I have never noticed a bit of distortion while watching movies. Believe me, I would have noticed as I am stickler for such things.

    A new receiver, unless absolutely necessary, is not an option as we are on a budget that would not allow an upgrade. Furthermore, as part of that budget, we are looking at an SVS PCi sub, the smallest one (thanks go to Ron Stimpson for his excellent customer relations).

    If you don't mind could you explain the crossover via the sub you mention above?

    In the end, unfortunately my pro-Sony attitude doesn't seem to have gained me anything in this endeavor. Better I had stuck with a couple other brands for a receiver that I am familiar with and have owned in the past (Denon or NAD).

    Thanks again.

    Father John
     
  8. MikeTz

    MikeTz Stunt Coordinator

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    Father John:

    In the theater mode most receivers can be programmed to send the lower frequencies to the powered subwoofer and higher frequencies to the speakers. The point in the frequency spectrum where the receiver switches from sending input to the sub and sends input to the speakers is called the crossover frequency.

    Most receivers have a default setting at 70/80Hz meaning frequencies below this value are sent to the sub and frequencies above are sent to the speakers.

    Amplifiers spend most of their energy reproducing the bottom octaves of the audio spectrum. It takes more energy to reproduce the long wavelengths (bass notes) at the bottom of the spectrum. You have two amplifiers in your system, the receiver amp and the subwoofer amp. The subwoofer amp is usually high power and specifically designed to power the sub efficiently.

    Programming your receiver for a crossover frequency above 70Hz (like 100/120Hz) puts more burden on the subwooer amp to reproduce the bottom of the spectrum. But the subwoofer was designed to do this. It also eases the burden on the receiver, especially if the reciver is modestly powered, because now the receiver does not have to reproduce as much of the bottom part of the audio spectrum.

    So go into the Sony manual and figure out if the receiver will allow you to set the crossover frequency to around 100/120Hz. If so, experiment with settings between 70Hz and 120Hz to get the best sound.

    MT
     

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