Hi Folks
I've got some 40L boxes, a pair of SB acoustics 8", a pair of Vifa 5" and a pair of Seas 27TDFC. I also have a 3 way digital crossover (DBX), but my only amplification at this point is a Marantz 7.1 HT amp. What are the down sides of using this style of amp…it has 70W pc, discrete inputs….?
What do other DIYers do for active home audio when they don't have the budget for more expensive 6 ch amplification? The idea of 3 separate amps is just too messy….
I've got some 40L boxes, a pair of SB acoustics 8", a pair of Vifa 5" and a pair of Seas 27TDFC. I also have a 3 way digital crossover (DBX), but my only amplification at this point is a Marantz 7.1 HT amp. What are the down sides of using this style of amp…it has 70W pc, discrete inputs….?
What do other DIYers do for active home audio when they don't have the budget for more expensive 6 ch amplification? The idea of 3 separate amps is just too messy….
The usual issue with receivers is the very ambitious power rating, usually with only one or two channels driven.
For this kind of application, that is usually not an issue because most music anyway does not have equal energy in all octaves.
The actual amplifiers can be easily bettered by a DIY effort, but in a snap it will work reasonably well. A quick look at the service manual will show you why, or a quick look at the insides. Receivers are cheap for a reason.
For this kind of application, that is usually not an issue because most music anyway does not have equal energy in all octaves.
The actual amplifiers can be easily bettered by a DIY effort, but in a snap it will work reasonably well. A quick look at the service manual will show you why, or a quick look at the insides. Receivers are cheap for a reason.
Thanks for the reply. It addresses a good point about the energy across the diff octaves. I would have thought the HT amp would work OK as it would only be working hard on the lower octaves, leaving the other amps just idling along?
I have made a few chip amps which I think would be fine for mids and tweets but lacking enough power to drive the woofers with sufficient headroom. Are there any DIY amp projects specifically tailored for this application?
I have made a few chip amps which I think would be fine for mids and tweets but lacking enough power to drive the woofers with sufficient headroom. Are there any DIY amp projects specifically tailored for this application?
While sangram is not far off on the issue of "hopeful thinking" in regards to the real world power ratings of HT receivers, I'll part ways with him on the sonic qualities. Over the past several years, I've helped set up 2 5.1 systems for family members with Marantz SR models, as well as upgraded my own from a Denon to Onkyo.
"Cheap for a reason" - certainly some of the low end ($200 etc) would qualify there, but that's a pretty broad generalization.
The real issue with the particular application (tri-amping) named is that while many multichannel receivers may have discrete inputs, the onboard DSP is programmed for surround processing using the internal amps, some of which may be assignable for either active or passive bi-amping of front mains, or to power a second zone with separate signal.
If the DBX provides all the required crossover filter functions and a master level control, it could well work with the Marantz in a pinch, but you'd be restricted to the number of line inputs on the DBX, and whatever surround processing would still be possible would likely be far more complicated -particularly if trying to use the Audyssey set up - which works like a charm as when implemented as designed.
Most of the middle of line on up models also feature line outputs for all the surround channels; the same maker will gladly upsell you to separate multichannel amps - either in a single or multiple chassis. If extant, I'd recommend using those, and something along the lines of this amp and appropriate power supply
Sure Electronics AA-AB34181 6x100W TDA7498 Class-D Amplifier Board
You could retain the very extensive functionality of your surround receiver, including powering the remaining channels / separate zones: use the receiver's pre-line output for front L&R into the DBX and go from there. * Yup, that's gonna mean at least two extra boxes ( the DBX and Sure amp), but you sorta knew that was coming, right?
A friend of mine is using one of the 4 channel Sure amp modules with outboard SMPS to power a pair of push-push sub woofers in his 2.1 TV system, and it works like a charm.
*edit - My current Onkyo is one of those models that allows for on-board digital XO and active amplification of front mains - at the penalty of sacrificing amp channels assignable to front height or width. Again, using the Audyssey auto calibration routine, which takes about 10 minutes if you allow for the full XT32 calibration and EQ - it's a breeze to use - the crossover frequencies are selectable starting at 250Hz up to 6K or so (I only use below 500Hz for "FAST" type 2-ways). I'd imagine that the auto set-up calibration procedure when using an outboard XO and tri-amping would be a bit more complicated, so a more experienced voice could pipe in with suggestions there.
"Cheap for a reason" - certainly some of the low end ($200 etc) would qualify there, but that's a pretty broad generalization.
The real issue with the particular application (tri-amping) named is that while many multichannel receivers may have discrete inputs, the onboard DSP is programmed for surround processing using the internal amps, some of which may be assignable for either active or passive bi-amping of front mains, or to power a second zone with separate signal.
If the DBX provides all the required crossover filter functions and a master level control, it could well work with the Marantz in a pinch, but you'd be restricted to the number of line inputs on the DBX, and whatever surround processing would still be possible would likely be far more complicated -particularly if trying to use the Audyssey set up - which works like a charm as when implemented as designed.
Most of the middle of line on up models also feature line outputs for all the surround channels; the same maker will gladly upsell you to separate multichannel amps - either in a single or multiple chassis. If extant, I'd recommend using those, and something along the lines of this amp and appropriate power supply
Sure Electronics AA-AB34181 6x100W TDA7498 Class-D Amplifier Board
You could retain the very extensive functionality of your surround receiver, including powering the remaining channels / separate zones: use the receiver's pre-line output for front L&R into the DBX and go from there. * Yup, that's gonna mean at least two extra boxes ( the DBX and Sure amp), but you sorta knew that was coming, right?
A friend of mine is using one of the 4 channel Sure amp modules with outboard SMPS to power a pair of push-push sub woofers in his 2.1 TV system, and it works like a charm.
*edit - My current Onkyo is one of those models that allows for on-board digital XO and active amplification of front mains - at the penalty of sacrificing amp channels assignable to front height or width. Again, using the Audyssey auto calibration routine, which takes about 10 minutes if you allow for the full XT32 calibration and EQ - it's a breeze to use - the crossover frequencies are selectable starting at 250Hz up to 6K or so (I only use below 500Hz for "FAST" type 2-ways). I'd imagine that the auto set-up calibration procedure when using an outboard XO and tri-amping would be a bit more complicated, so a more experienced voice could pipe in with suggestions there.
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I hope your experiment with it and report your findings. I have not actually done it with an HT receiver but I have read about audio enough it by far it is the speakers transducers that influence the ultimate sound you hear rather than the electronics and according to everybody except those with a vested interest in selling or justifying there astronomically expensive purchases, pretty much the consensus is that amps are not an issue if operating within its power limitations. That said, some cheaper HD receiver such as the Sherwood line will only drive down to 6 ohms I'm so that may be a factor with some drivers.
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I use a Denon HT receiver that is a few years old for exactly this purpose. It has 7 inputs for it's 7 amp channels (I only use 6) and it works fine. I will eventually replace it, but not for sonic reasons. It's just much larger than necessary and doesn't fit in well with the furniture it sits on. I'd also like to go completely differential (like most pro gear) too. But the Denon was free (I already had it) and had remote volume control, (which is handy) so I've procrastinated building a new amp for 3 years....
Soldermizer - I'd suggest that in any room in which even a modest multi-channel surround system is attempted, the degree of synergy between the room and the speakers is at least as important as the speakers themselves. It's not unheard of to have more "speaker system" than a small room can accommodate, or one with incompatible dispersion characteristics, the results of either of which can be easily as frustrating as an undersized system - if not more so when money was thrown at it because "speakers matter the most"
Horses for courses, and all that
Horses for courses, and all that
It sounds like it works fine - at least as a great tool for designing crossovers with a view to more specific amplification at a later stage. I have looked at the class d amps but I'm not sure they're gonna sound better than the HT amp . Also the fan (noise) and switch mode power supply puts me off - I guess I'm and old school A/B guy……although I'm prepared to be proved wrong. Cheers.
Tex: re fans - note that a lot of the higher powered HT receivers and amps have them (my Dayton APA150s for example) , and the noisy spinning hard drive in my cable provider's PVR is louder than any of those or SMPS fan I've ever heard. It's one of those ARRIS Gateway 2 part jobbies which has six tuners and at any given time several dozens of hours of series recordings to catch up which can't be copied or transferred to another device, so I'm stuck with it unless it completely self destructs .
That's something I've had happen several times with an older Motorola with outboard SATA storage drive - not a happy camper with that combo.
That's something I've had happen several times with an older Motorola with outboard SATA storage drive - not a happy camper with that combo.
The only real downside is making sure all the internal processing is disabled.
That said, 6- channel amps can be had cheaply. Look for whole-house systems being removed and parted out.
The only real downside is making sure all the internal processing is disabled.
That said, 6- channel amps can be had cheaply. Look for whole-house systems being removed and parted out.
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