Inifinty speakers and bang for your buck

[jehrico76]

Originally Posted by GLBright

Re: sub amps in Infinity speakers.

I think Infinity felt that their major competitor in their niche was Definitive Technology who was known for their amplified speakers. I have a pair of Compositions Overture 3s and a pair of Interlude IL-60s so I may be biased. I admit to having never had an Infinity speaker before these. However I do find both speakers to be eminently satisfying with both music and movies. Since most people today buy subs the trend has ended for almost all powered towers. But I do like being able to realistically set the front speakers to "Large".

Greg

I didn't mean to insinuate that amps in a speaker equates to a drop in quality (although I'd never own amplified mains). However, the introduction of the Ovtr series and the discontinuation of the Kappa series marked a significant change in philosophy for Infinity. I don't know when Arnie Nudell (if I recall his name right) left the company, but I know it was well before the Ovtr series. He didn't design the Kappas, but many of their better lines up to and including the Kappas were based on his philosphies regarding speaker building and design that he had brought to the company while he worked there, before he went and started Genesis. Anyone who is intimately familiar with older style Infinities, in my experience (I used to sell Infinities them from '96 to '99 while I was in college) typically don't take as well to their newer lines. Maybe it's a familiarity thing, I don't know. I've never cared much for Infinity's sound since that fundamental change in philosophy back then. Doesn't mean they're bad, but for someone who has had an older pair of Infinity for some years, I'd be willing to bet that they'd be less inclined to take to anything Infinity makes that plugs into a wall, or really, any of their newer lines at all. For better or for worse, they don't sound anything like the old Infinities.

[wje]

Originally Posted by ZXLNT

Pictures of them are just about all I can find.. I can't seem to find the Primus Towers in Cherry

If the cherry finish on the Primus line is the same vinyl veneer that is used on the Beta line, then ... I'll have to admit I don't like it at all. It just looks too fake. I had a chance to see the Betas in cherry. Needless to say, I quickly chose black.

[JohnR_IN_LA]

Originally Posted by heartsurgeon

look at this...you'll be hard pressed to find better/more for this price:

infinity beta 50 5.1 setup


i've bought from them, and they were prompt and reasonable to deal with.

the price i thought was unbeatable.

Eh ... i dont know about the pricing.

You should definitely be able to get one of their better subs at $1900, either the 500 watt 12 inch with room correction, or the 650 watt CSW-10 with room correction. And also free shipping

It does look like an excellent set of speakers otherwise...

[jdurbin]

I got a store model Infinity CSW-10 without the RABOS kit for $300 ($700 off list) a few weeks ago at Ultimate Electronics and then I sent an email to Infinity and they sent me a free RABOS kit.

I am searching for 5.0 speakers to replace my Cambridge Soundworks system and I had not really considered Infinity but the reviews on the Betas have been quite positive. Ultimate AV Magazine listed them as a 'Gold' system - kind of an editor's choice for the mid-fi. The reviewed system was Beta 50s, C360 and the 250s at the surrounds. Ultimate Electronics has them for 20% off MSRP and I don't get excited until it is 35% - 40% off MSRP. I didn't realize CC stocks them. I need to check that out.

The entry-level Revels are very, very similar to the Betas. Ultimate AV Mag has a review of them also. The measurements look slightly better than the Infinity Betas but they are tough to find and about 20% more than the Betas.

http://ultimateavmag.com/speakersystems/805infinity/
http://ultimateavmag.com/speakersystems/1205revel/

[jdurbin]

Originally Posted by heartsurgeon

look at this...you'll be hard pressed to find better/more for this price:

infinity beta 50 5.1 setup


i've bought from them, and they were prompt and reasonable to deal with.

the price i thought was unbeatable.

I would avoid purchasing from an unauthorized internet dealer. Plus, the CSW10 subwoofer is so much better than that one. Buy direct from Infinity via eBay to get the warranty or buy closeouts / floor models at CC, UE or one of the other big box stores. (Hey, that reminds me that I need to check out Nebraska Furniture Mart!)

[jdurbin]

Originally Posted by jdurbin

I would avoid purchasing from an unauthorized internet dealer. Plus, the CSW10 subwoofer is so much better than that one. Buy direct from Infinity via eBay to get the warranty or buy closeouts / floor models at CC, UE or one of the other big box stores. (Hey, that reminds me that I need to check out Nebraska Furniture Mart!)

Buying everything but the sub from Nebraska Furniture Mart and then the sub from Circuit City results in a $2,200 price tag. $300 more than the unauthorized vendor. I think you can get better deal by negotiating and get the price below $2k.

[DeepFreeze451]

I am also thinking of the Infinity Betas. 2 50s, 4 Beta 20's.... 1 Beta CS360....

still working on a subwoofer in a year.

[JohnR_IN_LA]

I saw a comment in the Infinity review, that implied they couldnt handle volume like higher end speakers.

If these Revels are indeed cut from the same mold, I wonder if they also have this limitation?

Originally Posted by jdurbin

I got a store model Infinity CSW-10 without the RABOS kit for $300 ($700 off list) a few weeks ago at Ultimate Electronics and then I sent an email to Infinity and they sent me a free RABOS kit.

I am searching for 5.0 speakers to replace my Cambridge Soundworks system and I had not really considered Infinity but the reviews on the Betas have been quite positive. Ultimate AV Magazine listed them as a 'Gold' system - kind of an editor's choice for the mid-fi. The reviewed system was Beta 50s, C360 and the 250s at the surrounds. Ultimate Electronics has them for 20% off MSRP and I don't get excited until it is 35% - 40% off MSRP. I didn't realize CC stocks them. I need to check that out.

The entry-level Revels are very, very similar to the Betas. Ultimate AV Mag has a review of them also. The measurements look slightly better than the Infinity Betas but they are tough to find and about 20% more than the Betas.

http://ultimateavmag.com/speakersystems/805infinity/
http://ultimateavmag.com/speakersystems/1205revel/

[GLBright]

Jehr,
I appreciate your comments about the older pre-Harman speakers vs. newer models. I have a friend who once had some RS 4.5s (with the outboard crossover) along with some Quantum Jr's in a DPL surround setup with McIntosh power. Beautiful speakers. At the time I was really unimpressed. Looking back I know now that speaker placement and the room were responsible for the bad sound. It wasn't until I auditioned and purchased the Overture 3s that I had any idea Infinity made speakers I could love. And they are pre-Floyd Toole, IIRC.

Greg

[heartsurgeon]

i didn't buy the "system" but bought some individual beta speakers from them, and found their prices unbeatable. i agree, the sw-12 is better.

[PULLIAMM]

A good friend of mine bought some very expensive Infinities (I think they were Preludes, around $4000/pr.) Not only were they not a good deal for the money, but they sounded just plain bad. I have rarely heard such a harsh, spitty, fatigueing high end.

[Bangedup]

Pulliamm, what was your buddy powering the Preludes with? Yes any speaker that high of quality will sound like $hit if is not set up right. I would suggest a preamp amp set up like Krell, B&K, Cary, Mark Lev.,Red Rose, just to name a few.

[PULLIAMM]

Originally Posted by Bangedup

Pulliamm, what was your buddy powering the Preludes with? Yes any speaker that high of quality will sound like $hit if is not set up right. I would suggest a preamp amp set up like Krell, B&K, Cary, Mark Lev.,Red Rose, just to name a few.

You make a good point. He did use them with a receiver much less expensive than the speakers. Of course, I use exactly the same receiver (a Yamaha) with my Def Techs and get excellent results. (After hearing my system, he sold the Infinities and bought Def Techs himself.)

[Steve1856]

I just bought a set of Preludes and they sound amazing. What were your friends hooked up with? These speakers are very revealing of bad sources and cables. If you are running them with a receiver or cheap separates, then they will sound bad.

I am running them with an Anthem D1 with an Aragon 2004 MKII. These speakers are demanding on the amp as well. You need one that will double into 4 ohms.

Finally regarding the source I was using my Pioneer Elite DVD changer as my CD source (due to laziness) and finally switched to my California Audio Labs CL10 and the difference was night and day.

Just goes to show you don't put Farrari tires on a Hyndai.

[jdurbin]

As mentioned above, I got an insane deal on the CSW-10 subwoofer and I then read a positive review on the Infinity Betas. I auditioned them at Nebraska Furniture Mart on Monday and again last night. NFM had them for about 20% off MSRP.

I ended up going with some Klipsch Reference series that were being closed out.

The Infinity speakers have very good fit and finish and they certainly are efficient but the sound just didn't close the deal for me. I listened to some jazz on them and I had trouble picking out instruments from the soundstage. It just sounded like a wall of music. I realize this isn't a really good explanation. I had trouble putting my finger on it but I just wasn't willing to pull the trigger on them.

Would I have been willing to still go with Klipsch if they were 20% off like the Infinity speakers instead of 45% off? Tough to say. Perhaps not. I definitely love the Infinity CSW-10 at 70% off! And I think it will match the Klipsch just fine.

I realize the thread isn't comparing Klipsch to Betas but for almost $2k I just didn't think the Betas were worth it.

[Bangedup]

Pulliam-

I would agree, a Yamaha receiver in my opinion is a bad match for any set of Infinity speakers, because of the low watts they pull. Example Yamaha 2600 only pulls 500 watts of power, even the Pioneer Elite 72 and 74 only pull 540 watts of power. Infinity is NOT a very efficient speaker and you will find Denon, Onkyo, Marantz will give a much warmer sound over the Yamaha.

You must match the right power with the right speakers for great sound quality and when listening to any system set up, use music that is simple and something you are familiar with.

jdurbin-

When it comes to speakers it is not their job to change the sound of the music (color the sound), like Klipsch does. Just cup your hands over your mouth and talk......you will sound different.

A common problem is when people do an A B comparesent using the same volume level when comparing Klipsch vs Infinity. Two reason why this is bad. 1) Klipsch is VERY efficient. They have a sensitivity ratting of 95 to 97db. People mistake loud for clarity. Sensitivity has nothing to with sound quality. 2) The loud back ground noise of a retail environment is not ideal for A B comparing. The way the human ear works is by the sound waves hitting the muscle and bones in the ear. The louder the sound, the tighter your muscles get, not allowing you to hear all frequencies. It is a way your ears protect themselves. When you turn the sound down, your ears ring. That ringing in your ears is the muscles relaxing.

I hope this helps and I hope N.F.M. as a good return policy.

[plhart]

Interesting comments on the Beta series guys. I designed the entire series with the exception of the C250 and ES250 which was done by Brian C.

The Beta series was basically finished in November 2003. The speakers are made in Harman's Tijuana facility using a European hard vinyl that was originally employed on the Harman-Europe (since closed down) designed Alpha series.

All speakers in the series are of medium-high sensitivity which means for a 2.83 volt input they'll output an average of between 87.5dB for the least efficient Beta 10 to 90.5dB for the Beta 50.

All Beta speakers are rated at 8 ohms but the two three-ways, the 40s and the 50s get down to 4 ohms between 150-300Hz. By edict, no current Harman, JBL, Infinity or Revel speakers can measure below 4 ohms as was often the case with the Infinities in the past.

Many models of the new lower cost Revel series are close clones to the Beta speakers with different, non-CMMD drivers. Even the crossover boards in certain models are the same but with slightly different value components which better match the characteristics of the Revel drivers. Note however that there are a couple of Revel models which have no Beta equivalent and vice versa.

The Revel B12 is a CSW10 with a black painted cone and a different grille. This sub was the the best I've yet designed. It'll hit 104.5 dB at 1 meter at full output and was the source of much investigation after I left Harman because in many situations it could outperform, sound quality-wise, the big $4000 Revel 15" sub with passive.

All Beta speakers went through Harman's double-blind listening Multi Channel Listening Lab and beat out each of four competitive models (selected by Infinity sales) in its price point. They went up against B&Ws, Def Tech, Bostons, Polks and I believe (in a couple of instances) Klipsch.

Hope this helps. I'll be happy to answer questions.

[JohnR_IN_LA]

Wow thanks for joining and piping up. I've been an Infinity fan ever since I walked into a showroom in 1982, and saw EMIT tweeters pointing at me from about 5 pairs of Infinity Refs.

What were the challenges designing with those CMMD drivers? In theory they have excellent characteristics?

Also do you know if the Revel Concertas can take louder volumes without compression/distortion?
Not that I have ever tested the Betas to see when they start to slip, but that one reviewer in that link indicated they indeed have volume limits somewhat consistent with their price-class.

Ive always gotten the impression that Infinity gave their engineers more leeway and tools to excel, than most mass-market brands, is this true?

I have the Interlude IL120S, which seems to be the same as the Beta SW-12. I suppose the CSW10 would be an upgrade? . Congrats on designing a Revel, BTW

[spivey]

All of the local CCity's are saying they are discontinuing the 40 and 50 Beta models and have none in stock. One salesman said they are getting new beta models, but not for a few months. Is there any truth to this?

[mark russ]

What exactly are the main differences between the Alpha 50s and the Beta 50s?

Are the Beta 50s really that much of a significant upgrade?

[Bangedup]

plhart-

Did you get a chance to listen to the new Cascade series in the blind test?

If you know, why did they use the MMD drivers in the TSS-4000 instead of CMMD drivers? I know Infinity is having a hard time selling the 4000s system and has already tried a lower coast set up with down grading the rears and subwoofer.

My friends at a local retail competitor, had the opportunity to fly out to Harman in CA. for the hole training and testing program. Along with having a one on one with Dr. Tool.

spivey-

The guy at CC is full of it. There is no truth in a New Beta Series. If there is I will be first in line to get my hands on them.

[plhart]

[

QUOTE=JohnR_IN_LA]Wow thanks for joining and piping up. I've been an Infinity fan ever since I walked into a showroom in 1982, and saw EMIT tweeters pointing at me from about 5 pairs of Infinity Refs.

What were the challenges designing with those CMMD drivers? In theory they have excellent characteristics?

The CMMD cones utilized on the Betas are not noticably different to work with than a more commonly used mica filled polypropylene cone as is seen on many competitive designs. The CMMD sandwich design does however pay off big time in terms of cone resonance which is much higher and therefore further out of the pass band than most other materials. The Beta CMMD cones also have the most perfect balance of stiffness-to-internal damping that I've yet heard. This becomes evident when listening double-blind in the Multichannel Listening Lab to a Beta vs. one of the best competitors (with similarly flat on-axis responses) such as the Energys. In cases such as this one of the standout differences can usually be heard in the region from 1KHz to 2 KHz. It is this region which has beautiful second and third harmonics. With CMMD the harmonics retain their snap and their complex structures are more delineated whereas a polypropylene cone will have too much internal damping. The excess internal damping in this region can give a flatter measured response at the expensive of rounding off (damping) the transient leading edge signiture of the harmonics.

Also do you know if the Revel Concertas can take louder volumes without compression/distortion?
Not that I have ever tested the Betas to see when they start to slip, but that one reviewer in that link indicated they indeed have volume limits somewhat consistent with their price-class.

The answer to your question is maybe, depending on the Beta model you're talking about. The Beta 10, a 5.25" two-way has a large box for it's driver size. The box dimensions of all models were determined, believe it or not, by the European cosmetic designer working with Infinity Sales and Marketing. I was not allowed to decrease the box size so as a result the little 5.25" driver does not have the degree of control (from proper bass reflex alignment) that I like to see in my designs. Thus the Beta 10 will probably "unload" at a lower volume level than would a 5.25 Revel over which the design and box dimensions Revel designer Mark G. had more of a say.

Most of the other Beta models had no such dimensional oversizing and thus should play just as "loudly" (a really relative term) as a same-configuration Revel. The Betas do have fairly good quality crossover components, not quite as good as the Revels, but high quality enough that (for example) core saturation never becomes a problem (before the driver is overdriven).

Ive always gotten the impression that Infinity gave their engineers more leeway and tools to excel, than most mass-market brands, is this true?

Not really. The bill of materials for each model has a fixed maximum cost from the beginning. The retail cost of a specific model is determined by Sales and Marketing from the outset because an Infinity speaker must compete pricewise in the marketplace with competitive models of similar configuration.

I have the Interlude IL120S, which seems to be the same as the Beta SW-12. I suppose the CSW10 would be an upgrade? . Congrats on designing a Revel, BTW

[/quote]

The Interlude was an earlier model designed I believe by Bill D. The Beta SW-12 was my "newer" design. The port tuning is completely different. You'll never hear the port make any noise because a) of the different configuration in conjunction with b) what is internally known as the "friend's circuit", the low frequency high pass equalization curve applied within the amp. There are a couple of other tricks within this same amp platform which allow the driver to be slammed a bit harder while still protecting the amp.
Yes the CSW10 is definitely an upgrade over the SW-12.

[plhart]

The Alpha Series was designed and produced in Europe before that facility was shut down. To my knowledge none of the Alphas went through the Northridge, CA Multichannel Listening Lab (Floyd Toole's and Sean Olive's double blind listening facility) for approval.

The Alpha 50 samples we tested at Northridge when I was first developing the Beta series had (IMHO) inferior quality drivers and crossver parts and they measured and sounded noticeably inferior. However, Harman Europe Sales and Marketing had had fair success selling the Alphas in Europe so they insisted that the Alphas be measured and included in the first listening tests of the Betas.

As I recall, the European Sales guys did the Alpha/Beta A/B just once, for about two minutes, before it became clear to them that the Betas where in another class all together.

IMHO Yes...

[plhart]

Originally Posted by Bangedup

plhart-

Did you get a chance to listen to the new Cascade series in the blind test?

If you know, why did they use the MMD drivers in the TSS-4000 instead of CMMD drivers? I know Infinity is having a hard time selling the 4000s system and has already tried a lower coast set up with down grading the rears and subwoofer.

My friends at a local retail competitor, had the opportunity to fly out to Harman in CA. for the hole training and testing program. Along with having a one on one with Dr. Tool.

spivey-

The guy at CC is full of it. There is no truth in a New Beta Series. If there is I will be first in line to get my hands on them.

Nope, the Cascade series wasn't even on the radar when I left 2 1/2 years ago. Though knowing that the new rectangular driver was conceived and designed by An and that the Cascade series also has Pedro M's Constant Impedence wave guide on the tweeter I'm guessing the price/performance is almost unbeatable. These are two very talented guys...

I'm guessing the only "new" Beta models we might ever get in the States would be the BETA HCS models which have been available in the European market from the beginning. These little 4" two-ways rock! Plus or minus about 1 dB from 90Hz to 15KHz and only -3dB at 80Hz. I'd also guess that if the HCS' ever do get here they would pretty much signal the final months of production closeout for all Beta models...

[plhart]

If you know, why did they use the MMD drivers in the TSS-4000 instead of CMMD drivers? I know Infinity is having a hard time selling the 4000s system and has already tried a lower coast set up with down grading the rears and subwoofer.

Most of the Infinity drivers in the MMD and CMMD series are generic to their particular size and Series. That is, the 3.5" MMD driver used in TSS-4000 has the same Thiel-Smalls (is the same driver) as used in the TSS-450 and TSS-750. Inventory control, ya know?

The TSS-4000 was designed by the same very talented Bill D. who did the Primus and other TSS models. Bill has also done a couple of the Revel inwalls. The TSS-4000 was again a "spec" request from Infinity Sales and Marketing. They wanted to keep the low profile a multiple 3.5"-driver would provide for a center channel while being able to turn the stack vertically for left and rights so the 4000s would have some similarity to the multiple same-driver designs of Infinity's past.

Unfortunately, the physics of a 3.5" driver will still only allow it to get down to 130Hz or so and a multiple driver (horizontal) center can set up a heck of a cancellation pattern at the listening position unless some expensive individual outboard driver roll-off techniques are employed. Then you need to have enough available $$ left to spend on said techniques and even that's assuming there's enough room in the tiny enclosure to fit the parts in a manufacturable manner. From the obstacles Bill had to deal with this difficult design challenge he really performed a minor miracle performance-wise. IMHO though the S&M guys set the price point for the TSS-4000 system too high to begin with.

[MDhaliwal]

Originally Posted by Bangedup

Pulliam-

I would agree, a Yamaha receiver in my opinion is a bad match for any set of Infinity speakers, because of the low watts they pull. Example Yamaha 2600 only pulls 500 watts of power, even the Pioneer Elite 72 and 74 only pull 540 watts of power. Infinity is NOT a very efficient speaker and you will find Denon, Onkyo, Marantz will give a much warmer sound over the Yamaha.

You must match the right power with the right speakers for great sound quality and when listening to any system set up, use music that is simple and something you are familiar with.

Hmmm. I just got the Pioneer Elite 74, which I've loved so far and was considering the Infinity Beta 40 or 50 speakers to replace my JBL N38's. I haven't actually heard the these specific Infinity models yet, but I'm planning to get over to a CC or such and check them out, provided they actually stock them.

So you would think that the Infinity speakers would perform poorly with the new Pioneer I bought? I had actually looked for Marantz while I was shopping, but couldn't find a store around me that actually had one, let alone set up for testing.

[plhart]

Originally Posted by MDhaliwal

Hmmm. I just got the Pioneer Elite 74, which I've loved so far and was considering the Infinity Beta 40 or 50 speakers to replace my JBL N38's. I haven't actually heard the these specific Infinity models yet, but I'm planning to get over to a CC or such and check them out, provided they actually stock them.

So you would think that the Infinity speakers would perform poorly with the new Pioneer I bought? I had actually looked for Marantz while I was shopping, but couldn't find a store around me that actually had one, let alone set up for testing.

Re: The quote about Yamaha and Pioneer speakers not "pulling enough power". It is technically incorrect and makes little sense. RMS watts 20Hz-20KHz is RMS watts 20Hz-20KHz no matter whose name is on the receiver. Yamaha, Pioneer, Denon and all other makers of this good quality gear publish power ratings based on the same EIA/CEA test procedure. Having said that, if you're comparing "100 watt per channel analog amps" the receiver which weighs the most will usually indicate a heavier power supply which almost always relates to more ballsy and tightly controlled bass frequencies. (Like gas mileage ratings, power ratings for amps have some wiggle room for fudged numbers that the marketing guys just love to exploit.)

Smaller bass drivers are inherently less sensitive than bass drivers which have larger piston areas. So if you're comparing a Beta 40 at ~89dB/1 watt/meter to a Beta 50 which is ~90.5dB/1 watt/1meter what you'll have in the Beta 50 is a speaker which will play 1.5dB louder for a 1 watt input and will also go about 5 Hz deeper in bass before it rolls off.

The Beta 40 is much preferred by the Europeans who typically have smaller listening rooms than their American counterparts because the bass from the dual 6.5" drivers is smooth and blends more seemlessly into the midrange.

The Beta 50 on the other hand measured flat in the bass (versus the midrange and treble) in the Harman 4pi anechoic chamber but that was with the Beta 50 being virtually suspended in air. Put the Beta 50s in a larger, typical American listening space and you'll be able to basically get as much bass as you'll ever need just be the adjusting the distance from the side and rear walls.

Most times Europeans find this quantity of available bass to be overkill for both their listening tastes and their rooms. Personally, I would rather not listen to and know that the bass is being generated by the speaker. I'd rather listen to the music, not a side effect of the speaker. That why I would go with Beta 40s and a really tight sub like the CSW10 (properly RABOSed for the room/listening position).

[MDhaliwal]

plhart -

Thank you for your exceptional response. I had many of the same thoughts, though decidedly none of the in-depth details that you provided. While I like bass, I also don't want to have my music altered because of the equipment I'm using. My current subwoofer is a fairly generic KLH unit, since I can't really crank it up due to my neighbor. A good powered sub to supplement whatever might 'lack' between the 40 and the 50, could be a good fit, as I could simply turn down the sub as need be; a more involved task when trying to cut some bass out of a regular speaker, huh?

I think I'm going to try and find a store around me to audition the 40's and see how they sound. The goal was to get speakers that sound good and are less obtrusive to the living room than the N38's. Maybe cherry wood instead of black works?

Thanks again!

[mark russ]

So, plhart, would the Beta40 actually be a better match for the 360c Center speaker than the 50 due to the same driver sizes, or would you still recommend the 50 instead over the 40?

And thanks for your input.

[Bangedup]

plhart-

The Beta 50 and 40 have the same Sensitivity (2.83V @ 1m) of 91dB. So whats up with your numbers. If you were just using those numbers for examples, then you must know it takes twice the power to get 3dB increase, so for a 1.5dB increase it will take 50% more power for the Beta 40s to play at that dB.

You cannot compare MPG to AMPS. Receivers cannot make more power. That is like saying I have a 250hp engine and I get 300hp to my back wheels. Wiggle room..what? Watts and AMP are measured by the US Goverment called UL Listed. These are real numbers with no wiggle room.

RMS has nothing to do with Frequency. If you are willing go to ( http://en.wikipedia.org/wiki/Audio_power ) to see what RMS is.

RMS Values and Measurement
July 18, 1996

The following is to help alleviate confusion about measurement of RMS (Root Mean Square) values of AC voltage.

RMS, or Root Mean Square, is the measurement used for any time varying signal's effective value: It is not an "Average" voltage and its mathematical relationship to peak voltage varies depending on the type of waveform. By definition, RMS Value, also called the effective or heating value of AC, is equivalent to a DC voltage that would provide the same amount of heat generation in a resistor as the AC voltage would if applied to that same resistor.

Since an AC signal's voltage rises and falls with time, it takes more AC voltage to produce a given RMS voltage. In other words the grid must produce about 169 volts peak AC which turns out to be 120 volts RMS (.707 x 169). The heating value of the voltage available is equivalent to a 120 volt DC source (this is for example only and does not mean DC and AC are interchangeable).

The typical multi-meter is not a True RMS reading meter. As a result it will only produce misleading voltage readings when trying to measure anything other than a DC signal or sine wave. Several types of multi-meters exist, and the owner's manual or the manufacturer should tell you which type you have. Each handles AC signals differently, here are the three basic types.

A rectifier type multi-meter indicates RMS values for sinewaves only. It does this by measuring average voltage and multiplying by 1.11 to find RMS. Trying to use this type of meter with any waveform other than a sine wave will result in erroneous RMS readings.

Average reading digital volt meters are just that, they measure average voltage for an AC signal. Using the equations in the next column for a sinewave, average voltage (Vavg) can be converted to Volts RMS (Vrms), and doing this allows the meter to display an RMS reading for a sinewave.

A True RMS meter uses a complex RMS converter to read RMS for any type of AC waveform.

When taking readings with a non True RMS reading meter, a 120 Volt RMS sinewave will still measure about 120 volts RMS. This is because the meter uses the mathematical relationships shown below to give a proper RMS reading for a sinewave. However if used with a modified sinewave or square wave these meters will only read about 90-105 volts. Don't be misled, there is nothing wrong with the inverter or the meter, and to prove this try the following test. plug in a normal light bulb and check its brightness. If there is only 90-105 volts RMS available it will look orange as it would during a brown out. If it appears to have normal brightness the voltage is approximately 120VAC RMS.

You can see that improper measurement can easily lead someone to believe that a modified sinewave or square wave inverter is not putting out its rated power. For example, remembering that Power = Volts(90-105) x Amps (33) a 4000 watt inverter (24VDC input) would measure out at about 3000-3500 watts if a proper true RMS reading is not taken.

Normally True RMS reading meters are very expensive, such as the Fluke 87 series meters. However, Radio Shack now offers two models priced under $90.00. Check with Radio Shack for details and features.

A few handy things to keep in mind about RMS values that apply when dealing with a sine wave, are as follows:

Peak Volts AC x .707= Vrms
Vrms=1.11 x Vavg
1.414 x Vrms= Peak Volts AC
Vavg= .637 x Peak Volts AC

For a modified sinewave or square wave these equations do not apply, and the easiest way to deal with this is to invest in a True RMS reading meter. (For a square wave Vavg, Vrms, and Vpeak are all equal.)

This article was originally written and published by Trace Engineering, now owned by Xantrex Technology, in July 1996.


I dont want to start a pissing match, however I do want to learn as much as I can. So if you are willing, please take my commits with a grain of salt.

MDhaliwal-

So a amp that only pulls 4amps of power like the Pioneer 74 and 72 can have its power supply taxed harder when powering muti. channels. Compared to the Denon 3805 that pulls 7.1amps. There is a sound difference between the two receivers. The Pioneer does not have as warm of a sound as the Denon or Marantz. You will lose some detail in your mid range. Listen to different receivers and you will hear what I am talking about.