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Posted By: gearcruncher Looking for pre/pro all channels driven - 09/02/12 09:19 PM
Does anyone have pictures how to wire the back of the reciever using pre amps . Ive been looking for wiring schematics using google but nothing much comes up .Not many images show how a pre amp is connected to the receiver and then to the speakers
thinking about a new receiver but would like to make sure it has all the quality connections . I am new to pre amps , thus the question
Posted By: Ken.C Re: Looking for pre/pro all channels driven - 09/02/12 09:20 PM
Are you talking about using the receiver AS a preamp, or using the receiver as an amp with a pre-amp?

The second would be extraordinarily uncommon, while the first is pretty typical.

If it's the first, simply hook the pre-outs on the receiver to the amplifier and the amplifier to the speakers.

If the second, well, maybe you should reconsider.
using the reciever as a pre amp . There arent many pictures showing the wiring configuration out there .
Lets say I wanted 7.1 or 11.1 surround amplified .
Do many receivers have the capability of pre- amping all 7 or 11 channels ?
Posted By: Ken.C Re: Looking for pre/pro all channels driven - 09/02/12 09:48 PM
The higher end ones do. Just look for "pre-outs" as a feature.
Posted By: dakkon Re: Looking for pre/pro all channels driven - 09/02/12 09:56 PM
http://www.accessories4less.com/make-a-s...Receiver/1.html

Here is an Okyo that has 9.2 channel pre-outs.
My yammy 5063 with 90/per channel doesnt have the punch I want and its not pre amp capable . I am willing to go the extra mile with my next receiver as long as its got the pre amp connections I want .I listen to music with all 7 channels driven .I prefer 11.1 . This way I have room for upgrades in the home theatre as I progress .
With Axiom,s natural sound , am I looking at high end Denon ,Onkyo or possibly Marantz ,pioneer ?
Got any recomendations ?
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/02/12 10:10 PM
i can say only good things about my Marantz, used as a preamp.

i know for a fact that if i were to use the Marantz power amps, i would be short on power for lots of music and movie listening at realistic levels.

i use the Marantz only to drive the back surrounds, and with some movies that have lots of information in the back channels, the power stage gets very warm, not hot, so i installed a small fan to help get rid of some of the heat.

Close your eyes, see the music...
Originally Posted By: J. B.
i can say only good things about my Marantz, used as a preamp.

i know for a fact that if i were to use the Marantz power amps, i would be short on power for some music and movie listening at realistic levels.

i use the Marantz only to drive the back surrounds, and with some movies that have lots of information in the back channels, the power stage gets very warm, not hot, so i installed a small fan to help get rid of some of the heat.


Thanks JB . I have a pool table in the mix of my home theatre so rear channels being amplified would be a plus . I am using two M3,s as my rears . At present , they are powered by the yammy 5063 and the lows are not driven enough . They sound good but if I could amplify the rears in my system it would really help
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/02/12 11:08 PM
if i were you, aside from looking at AVR's with the # of channels you want, i would also look at how much power you need to reproduce cleanly the most demanding music/movie source you intend to use, and then double the power you will need (+3dB) just for headroom and caring for future needs. The front speakers along with the sub are the most demanding, power wise.

if you have a look at my room, you will see that it's quite small - around 1500 cu. ft. plus an open doorway to the kitchen = 3000 cu.ft. - and i sit about 6-7 ft from the front speakers.
when i play some demanding movie at Reference Level, the front speakers need around 300 Watts/ch.

if the AVR's power output is not sufficient for your needs, i would seriously consider either Emotiva amps or some pro amps from reputed makers, like Crown or Peavey or QSC or others; (QSC has a 6 year warranty).
those amps have the advantage of having sensitivity potentiometers, so it's much simpler to adjust levels between fronts and surrounds and the sub.

your Yamaha is 90 W/ch, but only when one channel is working; with all channels working at the same time, your effective power could be around 50 Watts/ch. Clearly not sufficient for some music and lots of movies at Reference Level.
Posted By: Boltron Re: Looking for pre/pro all channels driven - 09/02/12 11:50 PM
I have a Denon AVR-4311CI and it has preamp outs. From a power perspective though it claims 140W x 9 channels but in reality it can only drive 2 channels at 140 Watts. I actually use a 3 channel ADA1000 to drive my M80s and VP150, so I use the Denon preamp out for the fronts and center. The Denon handles the surrounds and rears.

The Denon is quite good, I would recommend it.
My daughter just moved out of the basement giving me an extra 900 square feet of listening space . Basement theatre is planned to be 3000 square feet with the exception of a bathroom . I tell ya , these older homes with the oil furnace built in the centre of the home only makes my efforts a tad more difficult . Do I move the furnace or build around it lol . With some proper dampers , I am sure i could stuff a new small efficient gas furnace in one of the corners which would give me more room to play .
Your suggestions so far are excellent . Keep em coming
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/03/12 10:34 AM
gearcruncher, in your calculations, don't forget that cubic feet is the important thing in audio;
sound "fills" a room, from floor to ceiling.
after that, it's distance from the sound source; square feet doesn't come in the equation.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/03/12 06:33 PM
gearcruncher,

have a look at this post, you might find it interesting:
http://forum.blu-ray.com/showpost.php?p=6407443&postcount=13400
Posted By: fredk Re: Looking for pre/pro all channels driven - 09/05/12 04:12 AM
Quote:
if you have a look at my room, you will see that it's quite small - around 1500 cu. ft. plus an open doorway to the kitchen = 3000 cu.ft. - and i sit about 6-7 ft from the front speakers.
when i play some demanding movie at Reference Level, the front speakers need around 300 Watts/ch.

How did you get to this number?

Originally Posted By: J. B.
gearcruncher, in your calculations, don't forget that cubic feet is the important thing in audio;
sound "fills" a room, from floor to ceiling.
after that, it's distance from the sound source; square feet doesn't come in the equation.

Physics dictates that it is distance from the sound source that determines the power required.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 11:59 AM
"How did you get to this number?"

Just some measuring and maths.
numbers are approximate but close.
some movies take more than 300 W/ch for the FR/FL speakers.
Posted By: Ken.C Re: Looking for pre/pro all channels driven - 09/05/12 12:14 PM
JB, that's FAR higher than any number I've seen before. Love to see your math.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 01:16 PM
I put a Watt meter in between the wall socket and the amp.

once a movie or music CD is ended, i check the maximum wattage indicated on the watt meter, multiply it by 0.7 and this gives me the approximate # of Watts that were sent to both front channels; i then divide this number by 2 to get Watts/channel. (The QSC amps are about 70% efficient).
this is not precise in any way, but it does give me an idea about what's going on, power wise.
the best instrument for this would be a peak hold function on an oscilloscope.


when i want to know the movie's max SPL at my MLP, i put an SPL meter on the nearby armrest with the meter set to "peak hold" and "Fast".
this is quite precise, as the meter has an accuracy of +-1 dB and is user calibrated; Freq. Resp. is 20-12 500 Hz, and readings are taken with the Flat "curve".
The flat curve takes into consideration bass frequencies without attenuating them, like C weighting does. it shows the real bass level, in a linear manner.

one must never forget that instantaneous power peaks can be 10-20 dB higher that the average or RMS value. this is very important because caring only for average levels will mean peaks will be clipped.

most of the time, very high power demands last only small fractions of a second and as long as there is no distortion (clipping) in these instantaneous signals, one is not aware of them.
the more those peaks are cut off, the more distortion that can be heard.

of course, this does not apply to highly compressed music.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 04:25 PM
as i now have the time, let me give an example.

a few days ago i played the movie Super 8 at Reference Level; once it was over, i checked the Watt meter to which the FR and FL speakers are connected to the house current, through one QSC amp.
it said Max Watts = 1278 Watts. that's a total for 2 speakers.
for one speaker, we divide the number by 2 = 640 Watts/ch.

the amp efficiency is around 70%, so i multiply 640 Watts by 0.7 which gives around 448 effective Watts for one speaker.

now, the sensitivity for the M80 is 95 dBSPL/Watt/meter, in room.
as i sit at a distance of about 2 meters, then i get around 91 dBSPL/Watt/2 meters. The loss for doubling the distance is 6 db, but that's for open spaces; in my room, it's more like a 4 dB loss.

going from one Watt to 448 Watts is an increase of around 26 dB;
so, 91 + 26 = a SPL of 117 dB for one speaker.
the total output for the 2 front speakers is doubled, to 120 dBSPL, at 2 meters (MLP).

then, my SPL meter said that the loudest peak registered was 122.3 dB/flat scale.
I think the difference between 120 Db and 122.3 dB comes from the fact that the subs have to be taken into account as well as also the 4 surround speakers.

this is all approximate, but should be quite near the real numbers.
true peak power indicators are too costly for my needs.

if my method is wrong or does not make sense, please tell me how, i would be grateful for that.
Posted By: pmbuko Re: Looking for pre/pro all channels driven - 09/05/12 05:50 PM
J.B., what does the watt meter show when the amplifier is powered on, but no source is currently playing?
Posted By: Ken.C Re: Looking for pre/pro all channels driven - 09/05/12 06:00 PM
I think what you've got there is the instantaneous power, rather than the RMS or average power, which could be distorting (ha!) the discussion somewhat.
Posted By: pmbuko Re: Looking for pre/pro all channels driven - 09/05/12 06:13 PM
Keep in mind that the Pin portion of an amplifier's efficiency calculation -- a ratio of Pout/Pin -- is measured after the electricity from the wall has passed through the amp's power supply, where some loss inevitably occurs.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 06:47 PM
if my memory is intact, the PC12-Plus (Bash) shows around 22 Watts on stanby and i know the PC13-Ultra (Sledge) is at 6-8 Watts.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 06:59 PM
i wrote this to illustrate that, even with the efficiency of the Axiom speakers, the power needs for good reproduction of (mainly) movies is higher than we often suppose. 10 Watts or 100 Watts per channel is, in most situations, simply not enough power to give a crystal clear rendition.
this may well be the reason why some people who have 100 Watts/ch. find that suddenly their speakers "open up" and gain lots of transparency when they change their amplifier for a much stronger one.

the SPL meter readings are peak readings, at 0.125 second, but not instantaneous. as regards the Watt meter, i don't know the sampling time they use.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 07:05 PM
Originally Posted By: pmbuko
Keep in mind that the Pin portion of an amplifier's efficiency calculation -- a ratio of Pout/Pin -- is measured after the electricity from the wall has passed through the amp's power supply, where some loss inevitably occurs.


i know only that on the Internet, i've read a few times that my amp's efficiency is around 70%.
Posted By: fredk Re: Looking for pre/pro all channels driven - 09/05/12 11:34 PM
Originally Posted By: J. B.
i wrote this to illustrate that, even with the efficiency of the Axiom speakers, the power needs for good reproduction of (mainly) movies is higher than we often suppose. 10 Watts or 100 Watts per channel is, in most situations, simply not enough power to give a crystal clear rendition. ...

I don't have the time or energy to track down the difference between what you found and what is offered up in the standard formula for calculating power requirements.

Based on my experience to date, I'm still siding with the traditional calculator. My original receiver was rated at 90 wpc two channels driven and delivered crystal clear sound up to unreasonably loud levels (pushed it to 90db briefly one afternoon).

It can't hurt to have 300 wpc, but really, unless you have a very large space, its not needed.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/05/12 11:46 PM
what we're talking about here is that the main speakers should be able to do 105 DB and the sub 115 dB, at Reference Level, for those who like to have it like in the cinema or better as regards quality.

you're talking about max levels of 90 dB; that's a whole world of difference.
Posted By: fredk Re: Looking for pre/pro all channels driven - 09/06/12 01:28 AM
Originally Posted By: J. B.
you're talking about max levels of 90 dB; that's a whole world of difference.

I am? Where did I write that? wink

It may well be the case that the average and maximum were close to the same as it was no more than 30 seconds before I turned the system down. No need to annoy the neighbours and all.

I've also measured some classical pieces where I had peaks over 105db. This was on my 2808 which is rated at 110 wpc I believe. Again, all was very clean.

OK, you sucked me in. According to the Crown calculator at a distance of 3 meters, a listening level of 85 db, sensitivity of 91 db, head room of 20 db (a lot more than needed for most applications) and room gain of 5 db, I still need only 71 watts of peak power. Push that up to 25 db of headroom and you get close to 300 watts.

Some reading on power requirements from the Crown site. Note that their calculator is intended for outdoor use so you need to factor in room gain. Crown recommends 6db. I use 5.

Since Crown makes these commercial amps, and amps are usually driven harder in commercial applications, I'm inclined to take their recommendations seriously.

Now, I don't often listen at 85db. Its usually closer to 70, so to give me that 20 db of headroom I crave, I need a whopping 2 watts. grin

By the way, have you checked out the Peavy IPR series? The folks at Danley Labs did some testing and these things are the real deal.
Posted By: JohnK Re: Looking for pre/pro all channels driven - 09/06/12 01:52 AM
Jacques, rather than getting into the complexities and possible inaccuracies of using those watt meter numbers and that amplifier efficiency figure, I'll analyse the needed power in the way I always do. First, as you point out, to play at the movie "reference level"(which I'd never do, being too loud for home use)requires a maximum output of 105dB per speaker channel and 115dB for the .1 LFE channel. For an M80 to hit a 105dB peak at a 7' listening distance requires the following power: the 91dB at 1 meter for 1 watt input sensitivity(anechoic)is reduced 3dB at 2 meters(using the reduction of level per doubling of distance in home rooms found in the work of Dr. Toole and others), 1 watt being needed for an 88dB level. 100 watts would produce a 20dB increase, i.e., 108dB, and the peak maximum of 105dB per channel would therefore require 50 watts.

Both my studies of audio technology and my personal experience indicate that this is the reality of the situation. Receivers rated anywhere in the 100 watt area have ample capacity for safe listening levels with speakers of average or better sensitivity, such as the Axioms.
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/06/12 11:39 AM
i thought my method and tools were good enough for a reasonably close approximation of the power needed at Reference Level, but i seem to be wrong.

i'll have to give it a closer look so i don't fool myself with wrong logic or calculations as i seem to have done.

thanks. :-)
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/06/12 11:49 AM
Fredk,

when i was looking for new amps, the Peavy amps were right up in my list along with the QSC.
i had one model of each make in my final choice and i bought the QSC because the Peavy had a too high HPF

it's after i had bought the QSC that a Peavy engineer told me he could alter the HPF to the frequency of my choice, but it was too late.
What's HPF?
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/06/12 12:23 PM
HPF: High Pass Filter.
Thanks!
Posted By: dakkon Re: Looking for pre/pro all channels driven - 09/06/12 03:29 PM
Originally Posted By: J. B.

a few days ago i played the movie Super 8 at Reference Level;


I don't know how you can do that... When i watched super 8 i think i was listening at less than 1/2 of reference leve... Even at that level the whole damn house was shaking!!!!
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/06/12 04:35 PM
Dakkon, the reason could be that my room has been treated with some absorbing/diffusing panels covering about one third of the room, plus carpet and furniture. if my room was mostly reflective surfaces, i would never be able to do that.

playing Super 8 at Reference Level sounds very realistic to what i see on the screen, and not exaggerated at all.

i do have some movies that don't play well at Reference Level; the one that surprised me most for that was LOTR Extended Edition on Blu-ray.

it's probably made to the same level as the DVD's were: reference level -7 dB is excellent, but using reference level itself is way overblown.

you're invited for a day if you want to come, and other Axiom owners too.
Posted By: dakkon Re: Looking for pre/pro all channels driven - 09/06/12 05:30 PM
J.B. at reference level, i think my room would be well over 100db... Even at 1/2 of reference my room's sound level is 90db+ on average...


If i make it up to Quebec, it would be nice to stop by.
Originally Posted By: MarkSJohnson
What's HPF?

Home Parenteral Feeding

http://acronyms.thefreedictionary.com/HPF

Just FYI (For You Indirectly).
http://acronyms.thefreedictionary.com/fyi
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/06/12 08:56 PM
i just finished watching WOTW on Blu-ray at Reference Level.

the loudest passages registered 122.4 dBSPL (Flat weighting).
then i played again chapters 4 and 5, but this time with the SPL meter set at dBC; this time, the max reading was more according to the movie standards: 118.5 dBC.

the sound was always top quality, crystal clear and very detailed.

before starting a movie, i always crack open the door to my bedroom;
at the end of this movie, the crack was 5 inches wide. funny eh!

don't ask me about neighbors.
they all ran away a long time ago, just like the rats. ;-)
Posted By: J. B. Re: Looking for pre/pro all channels driven - 09/07/12 12:11 PM
Originally Posted By: pmbuko
J.B., what does the watt meter show when the amplifier is powered on, but no source is currently playing?


i checked again, and after 15 mins in standby, the Bash amp in the small sub consumes 18 Watts and the Sledge amp in the larger sub is at 8 Watts.
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