Axiom Home Page Forums General Discussion Advice from Axiom Owners It is OK to add Amps...

I really was at odds with how to share my most recent upgrade due to the fact that most here advise against adding external amplification. Or, I should say advise not to add if you don't need to. But how do we all know if we indeed need to, or not with all the variables involved in one's room.

I had folks pass me links to calculators which showed me I could reach certain db levels with "x" amount of power at "x" listening distance. It seemed to make sense from a safety stand point, but for those who may want to "test" their 80's, 60's, 150's or 180's you may just have to see what may be missing.

Now, I'm not a technical person, so do not expect a technical review. I will stress I was not disappointed with the performance of my AVR, but more so interested in what the 80's and 180 would do between their max handling and the proposed 130 watts my Integra was throwing at them. Also, Integra states the 50.1 will push 250 watts @ 4 ohm, but does not state how many channels driven, so again the "unknown" had me wondering.

After weeks of research, and lurking about many forums including here(thanks John, Fred & solardadd)I decided to pull the trigger. I purchased 3 Emotiva UPA-1's to power L/C/R. Seemed to be the best bang for the buck in the neighborhood I was willing to spend on the "unknown". I did not expect a lot, and had all intentions of sending them back if that was the case. Needless to say, they are not going back.

The specs on the UPA-1's state 350 watts @ 4 ohm. Not double the possible 250 Integra states, but closer to the 400 the Axioms can handle.

I should also state I have added GIK room treatments which helped before the amplification was implemented.

I noticed an immediate improvement in sound from the 180. Much more clear dialog, detail in sound effects, clarity at higher volumes, more pronounced bass. The 80's stood out more during music playback, they seemed to come alive with the added power. Again, more clear, accurate at louder volumes,etc. The Q's seemed to gain something from the AVR's rest as they became more pronounced as well.

So, I'm not sure if this is a positive note for amplification of the Axioms, or realization my AVR is not as strong as I had hoped.

Either way, my Axioms sound better in my room, to my ears, with the added power.

Brian

External amplification can be very beneficial depending on the room size, listening distance and speakers being used. In your case you are combining the M80's and VP180. This combo will be taxing on receivers for those that like to push their systems hard.

Brian, again there's no "added power" unless it's actually used. All of the observations that you note are consistent with playing at a louder volume.

Is it safe to say I am using the added power, and will surely be going deaf sooner than most?

Possibly. For a $50 investment in an spl meter you can know for sure. Or, you can just spend the money on beer and see if that counters the effects of excessive sound levels...

In theory.... (<--- Code for I don't really know what I'm talking about)

I should be able to use a volt meter to measure how many watts are being consumed by a speaker at any given volume.

As I increase volume, watt usage should go up. When I reach a point that increasing the volume does not increase watt usage I know the point I need to add an amp. Or am I laughably wrong?

On a related note... If my receiver is rated at 130 Watts/channel and the speakers at 400 Watts does that imply I can crank the volume knob all the way around with nary a worry for the health of the speakers while I wait for the receiver to melt?

I have a meter, so will the wife buy the beer excuse?

As you crank the volume beyond the avr's limits distortion will become evident. The question is will the avr fail before the distortion damages your speakers?

I think you are probably wrong on the first count. On the second count, you are absolutely wrong. You do NOT want your amp to clip, which is what happens if it tries to reproduce sound above and beyond its capabilities. If the amp clips, it could well damage the speakers.

I wish I could say it was the first time, or the last.


So that's why I need to figure out the volume limiter function on the receiver before the first teen party.

Now there is a good argument for extra 'unused' power. We know and understand (well, most of the time) our limits and the limits of our equipment. Teens seem not to.

Although when it comes to volume knobs, sometimes.
Adults + alcohol = teens

Allan Loft wrote what I think is the best article around describing power requirements. Easy to read for the dummies in the room (self). One watt is just fine for background noise, but for those of us who prefer things a bit louder, 100 watts becomes the minimum, not the max. http://www.axiomaudio.com/power.html

And his follow up article on head room description and power requirements. http://www.axiomaudio.com/dynamicheadroom.html

People preaching power needs should really understand these basic principles and make clarification to what they are talking about when they tell others that they “only need” a few watts of power.

Michael. It is simple physics, which is why I link to a calculator so often. There is no 'minimum' requirement per se.

It depends on room size (listening distance), listening volume, dynamic requirements and speaker sensitivity. Those are exactly the variables you enter into a calculator.

I have read and do like Alans articles on power.

No, Brian; that wouldn't be a safe assumption. The actual listening level apparently hasn't been measured, and that's necessary to know the actual power used by the speakers. If some or all of the observations are real rather than illusory(which is often the case with us)there's a strong probability that the listening volume was at least slightly higher. Amplifiers only add more voltage from their power supply section to the incoming voltage from the source material at any instant to make it drive a speaker loud enough to be heard easily(typically pre-amplifiers increase voltage 4-5 times and amplifiers 25-30 times). If they don't make it louder, they don't have any magical ability to somehow make the sound better at the same level. At a comfortably loud listening level(say mid 80s of dBs)speakers of typical sensitivity, such as the Axioms, use about 1 watt. How much more is needed for brief peaks depends on the source material. Some pop material is almost uniformly loud and has a dynamic range approachng zero. 2 or 3 watts might be the most used on such material. In contrast, some highly dynamic material, such as a few of the classical recordings I have, may have brief peaks as much as 20dB above the average and would require about 100 watts for that listening level(which I rarely actually use).

So no, there's no clear indication that any "extra" power over what your receiver could supply anyway was used.

One of the major flaws with this calculator is that room size and listening distance are not the same thing. How can listening at 4 meters (13 ft.) outdoors be the same as listening at 4 meters in a 2500 cu. ft. room?

Thanks for the clarification John. As I stated, I am not claiming to know what I'm talking about, and my post was meant for us folks who do not have the technical knowledge required to make decisions based on such. Some pre/post measurements could have been helpful, and interesting to say the least. I may break out the meter this afternoon just to "see" what I'm hearing. Let me ask this, your opinion of course, many claim there should not be SQ changes from amp to amp. But if volume and power levels are the same, meaning 100 watts from avr or ext amp, would the use of mono blocks make a difference? Just wondering why so many claim diffenrences in seperates vs. avr's. I really want to believe it's not just in one's head.
Thanks.

I love physics. I love math, and chess too. They all take discriminating opinion, perception and chance out of the situation/conversation and speak to facts, logic and numbers. Unfortunately, when it comes to subjects such as this one, and many others where “opinions” and “wives tails” play into the subject, physics then gets surrounded and lifted away within a whirlwind of bullshit. I generally avoid these topics anymore as there are hard liners who feel solid state amplifiers have their own sonic character and that they “add” all kinds of wonderful things to the electrons that make things sounds better. Then on the other side of the conversation are those who pull their calculators out of their shirt pockets, run numbers and then compare them to graphs and trends and tell you what sound looks like. I’m somewhere in the middle. I use outboard amps, but don’t really need them. I just prefer separate components over boxes crammed with crap that fight for realistate in the box. I’ve performed my own highly subjective and unscientific testing with and without outboard amps. I could not, (with a straight face), detect any notable difference in sound quality until the mean decibel level in the room reached 90 DB. At this level, the outboard amps in the mix definitely made a sonic improvement. But, as John has mentioned many times before, this is much too high for any sort of sustained listening unless that individual wants to suffer long term and irreversible hearing loss. But, for this last test, I started out with a receiver that had a robust power supply. I have also played with many other receivers “rated” at above 100 WPC and they sounded like crap above 70 DB. So when folks ask if receiver such-and-such will drive their speakers, I do more than look at their WPC rating. Some are simply better made than others and some brands are more honest than others. I’d recommend a 75 WPC NAD over a 125 WPC Yamaha any day of the week.

I agree whole heartily michael. This is why it is difficult for many to make a decision when looking for reinforcement on forums. I decided to just do it because I wanted to, not because I felt I needed to. Now the dilemma of trying to understand why I feel/hear a difference has started. The last time I had my meter out was before adding the sep amps, and I was getting readings above 90db with music and 100db+ during movies. I guess that may explain a possible improvement, but per the calculators I've been linked to my avr should be able to power to that level.

I'm just trying to help those who may be on the fence, or wondering like I was. By no means am I trying to start another argument or revitalize a topic that has been discussed over and over. This topic becomes popular due to the constant communication of possible difficulties of avr's driving Axioms, and the fact that they can handle more than what any avr can provide. I do truly appreciate everyone's help, and willingness to share information.

That is exactly why you add 4- 6 db for room gain.

I do not claim that this calculator is the be-all end-all definitive answer. It is a good guideline. If the calculator shows you are close to the limits of the receiver it may be worth while considering outboard amps. If, like me, you are only at the 60% mark of power available, outboard amps are a waste.

One problem with knowing you are "close to the limits of the receiver" using the calculator is many manufacturers of receivers are not totally true to their specs.

Brian, pretty much the same answer, and note that this isn't simply my "opinion", but rests on basic principles of how amplifiers work plus the results of controlled blind listening tests which have failed to show the differences sometimes claimed. In this latter connection, if you haven't studied the results of the classic amplifier blind listening test in Stereo Review you may find it enlightening. These results still stand unchallenged(i.e., unchallenged by contrary solid evidence, not just stubborn disagreement)despite later investigations.

Among the interesting points in the tests are the comments which are at the very end of the article showing the clear differences in "sound-stage", etc. which were described in open listening before the blind sessions began, but which disappeared when the name plates and price tags also disappeared. Especially interesting was the comment of the "believer" at the end of the tests(but before being shown his score)who apparently scored 7/16 on the Hafler/Futterman session 3, but still was describing the differences that he'd heard. Incidentally, the $12,000 pair of Futterman tube amplifiers, which apparently didn't have a flawed "tube sound" and which which were indistinguishable from the $220 Pioneer receiver in results, for some reason were off the market about a year later.

So no, the mono blocks have no capability to improve the sound in some mysterious fashion if the sound levels are carefully matched.

I just might try one of these some day. Review and more info here.

I'm looking at the non-dsp version for a couple of sub projects I may or may not ever get to...

Big difference in $$ non-DSP vs. with DSP.

Brian,

I am very much a noob to all of this but have been looking at the Emotiva amps as well as i happen to live where there HQ is. My theory is this, if you dont care about the money then who cares what a meter says, its like having a big v-8 but not driving it 150 mph, its still worth it :-)

I have heard my m22's on a different receiver (sony) from my denon and the difference is humorous so i can only imagine the difference when going to a separate amp. To me, my setup seems to almost "open up" at a louder than normal volume and that is the sound i truly love.

Some measurements on the IPR1600.

Those measurements don't tell a very complete story. Apparently you need pretty fancy (and expensive) equipment to measure properly.

The folks at Danley labs bench tested an IPR1600 and pushed it pretty hard without any clipping/distortion/shutdown issues. They agreed that the amp is able to properly deliver to its full specs. Its one heck of a bargain.

Note: This thing is able to handle 2 Ohm loads. Compared to Recievers and consumer amps, this thing is a beast.