I started this tread as a separate one following a user reporting about the lack of performance between active and passive subs. Perceived effect is not due to the inherent advantages of active over passive designs but due to manufacturers taking consumers for a big big ride
Any HT receiver would not be able to sufficiently power a subwoofer. A HT AV receiver has just maybe one power supply transformer (higher end models 2 at the most). These provide power to the ADC and DAC, dolby, dtx processors, displays, multitude of relays inside, 5 speakers and one sub woofer.
Sub woofers require lots of power. The amps inside a AV receiver can hardly power a subwoofer adequately which explains the lack of performance you face. I do not know much about HT receivers (but have designed sub-woofers for music extensively) but when I looked up the net for specs of onkyo 3100 this is the model that the user says has experience and felt passives offered poorer performance - it says the output is 130 W. Now please see this link below for specs of the unit and come back to this message
Onkyo HT-S3100 - 5.1-Channel Receiver/ Speaker Package | Model Information | Onkyo USA Home Theater Products
What the manufacturer says is that the amp can supply the front, surround and centers with 115 W each and does not talk of sub-woofer output here (i.e. the amp section). Start looking at the ambiguities now.
1. Is this the RMS power? No mention.
2. Nowhere does he say if this output would be maintained if all channels (front, centre, rear, subs, etc) are driven simultaneously. Also even for individual channels he says output is based on a 1kh reference frequency. As you know at any point of time you will have multiple frequencies in music (even movies) multiple instruments, voices, sound effects and not to mention their harmonics). So it is unlikely the amp can even power a single channel with complete bandwidth (20-20k)
3. Next take THD. 0.9% is very very high (0.01% is accepted as min in solid state audiophile equipment). And even that Onkyo says is 0.9% of rated power. Now whats that new term and what is the actual rated power. Keep searching it leads you to point 1 and 2 again. Without them answered this serves no purpose.
4. In speaker section look at claimed subwoofer frequency response. They claim 30 hz to 150 hz. Are they claiming a ruler flat frequency response. For 1 W input will the speaker produce 83 db/m (their claimed efficiency for sub) at 30 hz and and 150hz. It is almost impossible for a 8 sub to go down as low as 30 hz. 12 subs find it difficult. To claim that an 8 goes down to 30hz and maintains claimed SPL with ruler flat accuracy is a blatant lie and such a cheap claim that not even a college student who uses a 8 as sub in an earthen pot would utter this. 5 stars to Onkyo for having the guts to do this
5.Next look at the efficiency of the sub. 83 db/w/m. lets say sub is in the corner of a room and your listening position is 2 m away from it (very common) the efficiency of the sub is only 71 db/w/m now (remember 6db drop per meter). Power the puny amp with all channels driven and wait till we hear. If the sub-woofer can be heard its a remarkable achievement. Dont even think of performance or bass extension from these units.
This is the real reason for lack of performance by passive subs. Bad drivers, incorrect specs, exaggerated claims, puny amps and lies, lies and more lies
Buyers beware !. Understand the specs. If you dont, ask people who know about these things. It is better to be ignorant and ask friends that get fooled by salesmen and unscrupulous marketers.
Any HT receiver would not be able to sufficiently power a subwoofer. A HT AV receiver has just maybe one power supply transformer (higher end models 2 at the most). These provide power to the ADC and DAC, dolby, dtx processors, displays, multitude of relays inside, 5 speakers and one sub woofer.
Sub woofers require lots of power. The amps inside a AV receiver can hardly power a subwoofer adequately which explains the lack of performance you face. I do not know much about HT receivers (but have designed sub-woofers for music extensively) but when I looked up the net for specs of onkyo 3100 this is the model that the user says has experience and felt passives offered poorer performance - it says the output is 130 W. Now please see this link below for specs of the unit and come back to this message
Onkyo HT-S3100 - 5.1-Channel Receiver/ Speaker Package | Model Information | Onkyo USA Home Theater Products
What the manufacturer says is that the amp can supply the front, surround and centers with 115 W each and does not talk of sub-woofer output here (i.e. the amp section). Start looking at the ambiguities now.
1. Is this the RMS power? No mention.
2. Nowhere does he say if this output would be maintained if all channels (front, centre, rear, subs, etc) are driven simultaneously. Also even for individual channels he says output is based on a 1kh reference frequency. As you know at any point of time you will have multiple frequencies in music (even movies) multiple instruments, voices, sound effects and not to mention their harmonics). So it is unlikely the amp can even power a single channel with complete bandwidth (20-20k)
3. Next take THD. 0.9% is very very high (0.01% is accepted as min in solid state audiophile equipment). And even that Onkyo says is 0.9% of rated power. Now whats that new term and what is the actual rated power. Keep searching it leads you to point 1 and 2 again. Without them answered this serves no purpose.
4. In speaker section look at claimed subwoofer frequency response. They claim 30 hz to 150 hz. Are they claiming a ruler flat frequency response. For 1 W input will the speaker produce 83 db/m (their claimed efficiency for sub) at 30 hz and and 150hz. It is almost impossible for a 8 sub to go down as low as 30 hz. 12 subs find it difficult. To claim that an 8 goes down to 30hz and maintains claimed SPL with ruler flat accuracy is a blatant lie and such a cheap claim that not even a college student who uses a 8 as sub in an earthen pot would utter this. 5 stars to Onkyo for having the guts to do this
5.Next look at the efficiency of the sub. 83 db/w/m. lets say sub is in the corner of a room and your listening position is 2 m away from it (very common) the efficiency of the sub is only 71 db/w/m now (remember 6db drop per meter). Power the puny amp with all channels driven and wait till we hear. If the sub-woofer can be heard its a remarkable achievement. Dont even think of performance or bass extension from these units.
This is the real reason for lack of performance by passive subs. Bad drivers, incorrect specs, exaggerated claims, puny amps and lies, lies and more lies
Buyers beware !. Understand the specs. If you dont, ask people who know about these things. It is better to be ignorant and ask friends that get fooled by salesmen and unscrupulous marketers.
Go for them if you dont want to compromise.
