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New member Username: Real57vetteguyCanton, Nc United States Post Number: 1 Registered: Feb-09 | I have a Onkyo TX-SR805 receiver, PSB towers, JM LABS Sib&CUB (not using the cub sub) 12" Klipsch sub, Samsung 120 hz lcd, and PS3, I have all speakers besides the towers set to "small" the voumes for all small SIB speakers are set to between 6-8 depending upon room placement everything is set up using HDMI cables I am using direct TV as my provider. My tv volume is odd, When certain tv commercials play they seem to be 10db louder than the show or movie i was watching, movies through the blu-ray are awesome and music sounds good but I have blown both rears and sometimes on normal tv the highs sound as if all the speakers are blown. I do like occasional loud music volume. Have I purchased the wrong equipment? I also noticed that my electrician used very very small guage speaker wire when he wired the home for surround, could this cause a problem? |
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Silver Member Username: JrbayLivonia [Detroit area], Michigan USA Post Number: 696 Registered: Feb-08 | The loud commercials are simply that - loud commercials. The advertiser boosts the audio level to get your attention. Regarding the speaker wire, yes if the wire is too small and the runs too long then yes this could cause a major problem. Please see if this helps you: http://customconnectionsonline.com/faq10.html |
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New member Username: Dsmith901Tallahassee, Florida United States Post Number: 1 Registered: Feb-09 | I suspect the more likely cause is your receiver amps are clipping during the loud portions and the rear speakers are paying the price. If your receiver has preouts you can add a separate multichannel power amp and all your speakers will be more secure. You should use nothing smaller than 14 gage speaker wire all around - 12 gage is even better. |
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Silver Member Username: JrbayLivonia [Detroit area], Michigan USA Post Number: 697 Registered: Feb-08 | What would be the cause of the clipping Donald? I am also curious as to why you suggest nothing less than 14 gauge wire. |
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New member Username: Dsmith901Tallahassee, Florida United States Post Number: 2 Registered: Feb-09 | Clipping is caused by amplifiers being driven beyond the capability of their power supply, and it is the most common cause of speaker damage. Clipping results when the receiver (amp) is not powerful enough to safely drive a particular speaker at higher levels. In general, speakers are more likely to be damaged by low powered amps than high powered amps, because the low power amp is more likely to clip (distort) the wave form under heavy power demands. The speaker's characteristics play a part - the higher the speaker's sensitivity the louder they will play at a given power input, and the lower the impedance the more current they require to produce a given sound level. As for the wire, thicker wire (lower gage number) will pass more current safely, especially on long runs (50 feet or more) and power hungry speakers need to get all the power available to operate safely. Sending a high current through a thin wire is a fire hazard as the wire will get very hot. You might get by with 16 gage wire on very efficient speakers up to 40 feet or so (just an estimate) but it sounds like your rear speakers require a lot of current. If you replace them look for speakers rated at least 90 dB sensitivity or higher and 8 ohm (nominal) impedance. Unfortunately mass market receivers are notoriously overrated for power, the exceptions being Harman Kardon, NAD, and Sherwood Newcastle, so you might consider replacing your current receiver with one of those if you don't want to get a separate power amp. I suggest you read up on receivers and amps at this website below. Most of the articles are written for the consumer and I think you will find them very helpful in analyzing problems in your system. https://www.ecoustics.com/articles-index.html |
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Silver Member Username: JrbayLivonia [Detroit area], Michigan USA Post Number: 698 Registered: Feb-08 | That certainly defines it Donald and I agree totally. Not only from reliable sources but first hand experience as well but would you believe that a Blu Ray player and an Onkyo TX-SR805 are going to be susceptible to clipping? Since I would have never thought so that is why I asked. I back my information regarding speaker wire from sources such as this: http://www.roger-russell.com/wire/wire.htm There is no doubt of the value of 14 gauge wire, it is what I use almost exclusively so that I never run into potential problems with longer wire runs but blanket statements about it being the ONLY wire to use are untrue and confusing. For example, if the "very small gauge speaker wire" cited in Marks question that his electrician installed is in fact 16 gauge wire in run of less than 25 feet or so then that is probably not the problem here either. Of course the question remains, what is the problem here??? |
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New member Username: Dsmith901Tallahassee, Florida United States Post Number: 3 Registered: Feb-09 | I am not familiar with the Onkyo SR805 so I read the Secrets review here: http://www.hometheaterhifi.com/volume_14_3/onkyo-tx-sr805-receiver-9-2006-part-1 .html Notice that the power output drops considerably when the receiver is set to 4 ohm output instead of 6 ohm. The owner should use the 6 ohm setting to ensure best power output. IMO it is best to avoid receivers with selectable output based on impedance for this very reason. This is a feature designed to help pass certification but hide the fact the power supply is not adequate for high current and inefficient speakers (but then few receivers are). It would help for us to know more about the speakers - what their specs are - and how the crossover setting are set, as well as exactly what gage wire he is using. It may be just the speakers at fault, and he may need to get new rear speakers that match the front. |
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Silver Member Username: JrbayLivonia [Detroit area], Michigan USA Post Number: 701 Registered: Feb-08 | By simply looking up the speakers mentioned it would appear that the mains are rated at 6 or 4 ohms and that the JM Labs are rated at 8 so we have a discrepancy already, combine all that with inadequate wire and what may be a power supply issue (when settings are wrong and at full volume for extended periods I would imagine) and yes Houston, we have a problem!!! |