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"Quote: each contains two 2700VA toroidal transformers Each monoblock requires two 15A power cables, one for each amplifier stage."
Can JA or JVS confirm if these are bridged amps?
Cheers George
Evil Grinch proved no match for the visiting electrician. While our savior was here, I tapped his knowledge of the eccentricities of Port Townsend's electrical grid. When queried about the underground wiring to our house from the transformer across the street, he said, "Given the age of your house [1992], I am more than 99% certain that the wiring to the meter and your breaker panel is aluminum." After opening the panel, he shattered all illusions by declaring that the underground wiring from the main house to the second breaker panel in the detached music room was also aluminum.
What? Back in the spring of 2015, when we designed the music room, I spent a lot of money installing a dedicated line with two legs. One led to a single AudioQuest duplex outlet and a second, on a different breaker, led to a double-duplex AQ outlet, with four receptacles. We used 10-gauge copper conductors in metal-clad cable, the hot, neutral, and earth ground conductors twisted around each other instead of running parallel as they do in typical cable (think Romex). Twisting the conductors helps with common-mode noise cancellation, the grounded metal sheath shields noise, and the large, 10-gauge conductors reduce the resistance of the circuit. Nearly eight years later, I'd discovered that my entire dedicated line was fed by aluminum, which is notorious for adding noise to the line and muddying bass (footnote 1). No wonder that time and again, amplifiers sounded smoother, warmer, and more musical when they were plugged into an AudioQuest Niagara power conditioner or Stromtank battery power source rather than directly into the wall.
Knowledge is power when it leads to action. I moved fast. Distributor Wynn Wong would arrive from Toronto in less than a month, to install two Serbian-made Karan Acoustics POWERa monoblocks ($106,000/pair) for review. These monoblocks weigh an astounding 231lb each, with a shipping weight of 286lb; each contains two 2700VA toroidal transformers and a 210,000µF bank of custom capacitors. Each monoblock requires two 15A power cables, one for each amplifier stage.
I doubted that the Stromtank S 2500 Quantum MKII was equipped to handle such a big power draw while conveying the full dynamic capabilities of these amplifiers (footnote 2). I needed a viable alternative; there was no way I was going to compromise sound quality by plugging the POWERa's into outlets mostly fed by aluminum wiring.
First, Hans Frederickson of Frederickson Electrica man (and a company) that understands the needs of audiophilesmade room in his schedule for the two-stage wiring upgrade. Second, Wong agreed to travel to Port Townsend and install the amps with his assistant, Kenneth, ensuring that David and I would not be crippled for life by our attempts to haul them into place. Wong also agreed to bring a 6-outlet Acoustic Revive RTP-6 Absolute power box to help plug everything in.
Before electrical work began, I enlisted the assistance of power expert Ed DeVito of Audio Ultra in Sumner, Washington, near Seattle. I also consulted Garth Powell of AudioQuest. Rather than go with Audio Ultra's full AU3000 power package, which would have necessitated more electrical and structural changes than time and bank account allowed, we took a more modest approach. We replaced the music room's existing breaker panel with a Square D QD 100-amp subpanel that uses bus bars of tin-plated copper (footnote 3) rather than aluminum. We added a UL-approved EP2050EE surge protector/noise filter from Environmental Potentials, Audio Ultra's affiliate company, to provide, in Ed's words, "non-sacrificial protection from transient voltage surges and spikes" and to "optimize system performance by absorbing ... noise between 3kHz and 1MHz without shunting energy to ground." (footnote 4) We tested grounding, examined panel loads, and ensured that we met Ed's specifications as we created two in-phase 20A branch circuits to feed the audio system's dedicated outlets. Having two circuits allowed me to separate the amplifiers from the front-end components. We could do nothing about the aluminum wiring that ran underground from the transformer across the street to our meter, but most everything else was changed.
Some of this work took place two weeks into the review. The listening report that follows covers sessions conducted after everything was in place, settled in, and performing optimally.
Previewing the main character
What is this beast of an amplifier? Here's what I can share about the POWERa, from information provided on the Karan Acoustics website, by distributor Wong, and responses to questions sent to company founder and chief designer Milan Karan in Novi Sad, Serbia.
Karan, 57, initially made his living designing "sophisticated medical equipment" while building audio equipment on the side "just because of my passion for music." A guitar player for the joy of it, he created Karan Acoustics in 1986 after his musician friends kept saying "good things" about the amplifiers and preamplifiers he had built. A music lover who tests his equipment with all kinds of music but prefers live jazz and classical, Karan regularly attends concerts during travel to other cities and countries, and his nine employees are all music lovers who listen to designs together and compare prototypes, testing out small changes.
Karan Audio has been distributed in Europe and Asia for more than 25 years. North American distribution began five years ago after Karan met Wynn Wong.
"My goal was to make the POWERa the best sounding amplifier, without compromising anything," Karan wrote in an email. "I wanted to achieve a natural sound as close as possible to live music and build an amplifier that would not change the input signal in any way, ... just deliver a lot of power to ensure there is enough headroom to drive any speaker while providing air/transparency, separation among the instruments, etc."
Karan began designing his top-line Master Collection (topped by the POWERa) 10 years ago. "It's a huge, cost-no-object step up from its predecessors," he continued. "I put everything I learned from 30 years of medical and audio engineering into it.
"I would love to make the POWERa lighter without compromising the sound, but it's otherwise impossible to achieve a high output power capability like its 2100W into 8 ohms, 3600W into 4 ohms, and 6000W into 2 ohms." (footnote 5) Peak power is even higher, at 2400W into 8 ohms, he noted. "The weight comes from a high quality chassis with good acoustic and vibration isolation, overbuilt internal heatsinks, and high current/low-noise transformers. To achieve a natural, precise, focused, dynamic sound, the heatsinks are designed to eliminate acoustical and vibrational feedback to electronic components. You cannot have dynamics if the vibration affects the sensitive components. The PCBs are decoupled with a special kind of spacer and copper discs to allow the musicality and harmonics to flow."
The POWERa neither runs too hot to touch nor heats the room to an excessive degree. As Wynn Wong explained, "Karan amps may be class-A, but they don't run hot like traditional class-A amplifiers, which run a constant high bias. Because of the POWERa's 'sliding class-A bias circuit,' the bias level is adjusted based on the signal (from the preamp) in real time."
"The design is fully balanced, very high speed, and extremely quiet," Karan wrote. "I used the best possible components; some are custom-made for my company. I also selected the best PCB conducting and isolation material. The thickness of the copper on our PCB is much higher than usual. I tried many samples of different thickness and chose the right one by listening. The design of the PCB, the architecture, and component placement also affect the sound. I had to make small adjustments to further improve performance and ensure that components would not interfere with each other."
One of the POWERa's unique features is "a proprietary, in house designed, built in Line (mains) Conditioner." (footnote 6) Activation is by a toggle switch located on the bottom center of the rear panel, directly below the speaker cable outputs and the single-ended and balanced inputs. Counterintuitive though it may seem, power conditioning is engaged when the switch is in the "0" position and disengaged in the "1" position. (It's the opposite turning the amps on and off.) Karan claims the Line Conditioner acts in part as "an efficient DC 'eliminator'," and that its rating of 60A or more can cater to "at least three times more" than the maximum current and voltage flow required from the main power supply.
Each POWERa contains two toroidal transformers, one for each amplifier stage; each requires its own 15-amp power cable. Their IECs are located on each side of the rear panel, each beneath its power switch. There is no standby button. Asked the rationale for this two-cable, two-switch design, Karan replied, "It's not possible to connect two big transformers to one switch/fuse because they draw too much current. We did a comparison, and it sounds much better with two switches/power cords, one for each stage."
The POWERa's front consists of a central black glass panel on which the Karan logo and name are tastefully and moderately illumined in red. Flanking the black glass are silver-colored aluminum panels. The buffed silver aluminum top continues the front's geometric layout, with a large logo engraved in the center flanked by panels covered with small, heat-releasing holes. The CS2M footers, too, are "safe," being tall enough to enable the amp to be lowered and raised without crushing your fingers. Hernias are another story.
I asked Karan what setup he considers optimal. "The amplifiers will sound noticeably better with amp stands, but you still get decent sound placing them on the floor," he replied. "The CS2M footers are the latest model from Critical Mass Systems. Wynn distributes Critical Mass Systems, and he suggested a few years ago that I try their footers. They have greatly improved the sound."
Karan is currently developing prototype speakers that include a matching sub tower with active crossover. It takes six POWERa mono amplifiers to drive them. Prepare your mansion now!
Footnote 2: By email, Stromtank's Wolfgang Meletzky confirmed that the S2500 Quantum MKII can deliver peak power up to 2800VA/3s. "If the continuous consumption is 12A or below then it is no problem with dynamics with 8-ohm speakers. If you are using a 4 or 2-ohm speaker, we recommend using a higher performance Stromtank like our S4000 Pro Power or our top model S5000 High Power." The Wilson Alexia V's nominal impedance is 4 ohms.
Footnote 3: Silver-plated copper is even better, but it costs substantially more.
Footnote 4: Translation: The EP2050EE helps filter out noise from appliances, heating units, computers, dimmers, LEDs, and more.
Footnote 5: Such a high power rating is not achievable with US household power, even if each of the two power cords is on its own circuit branch, with its own 20A breakerthat's four circuit branches altogethertwo for each monoblock, for amplification only. Karan specifies the input power at 115V, so the maximum continuous power, with two 15A power cords and two independent circuits, is 2 × 115V × 15A = 3450W per channel. If we assume that the amplifier can draw the full 20A, despite the 15A-rated IEC connector, then each monoblock is capable of putting out 4.8kW of continuous power.
Footnote 6: The quote is from the website. As I learned from distributor Wynn Wong while editing this review, the "power conditioner" in the Karan is really just a DC filter. No doubt, it's a very well-executed DC filter.Jim Austin
"Quote: each contains two 2700VA toroidal transformers Each monoblock requires two 15A power cables, one for each amplifier stage."
Can JA or JVS confirm if these are bridged amps?
Cheers George
Looks like the Monoblocks are just bridged stereo.
I found the internals are the same as the stereo amp they have.
Karan Acoustics Master Collection POWERa Stereo.
And if they are bridged stereos, they would not double wattage into 2ohms as claimed from measured 4ohms (JA measured 2500w), if anything it maybe less than that 4ohm 2500 wattage into 2ohm, or worse become unstable also. Pity JA couldn't measure that 2ohm wattage.
Cheers George
Current limit , yes , unstable into 2 ohm doubt that very much....
To begin with, spending $100K on any product made in a far-away land gives me the jitters. It's not like a BMW or M-B that have local dealers to support it. If it fails, shipping this amplifier anywhere will be a project in itself (not to mention Serbia).
Next, I thought that a product needed some kind of deeper representation before a review would be published, but I could be incorrect. Just 5 dealers for such an esoteric, imported and expensive product seems like a gamble to me. I'll spend my money on a USA built and supported product first.
Finally, when I read that any reviewer has AC power issues in the home where the critical listening is performed, I have to discount the opinion on the sound produced. Has this power problem influenced all the prior reviews somewhat?
I had 2 dedicated 20 amp duplex receptacles installed for under $150 over 10 years ago, and I bought the cable and supplies. I don't have anywhere the need for such, but thought if one is serious about performance, a small price to pay for knowing there is no current limiting.
The other comments here are right on to me. Spending this kind of money and then maybe needing repair would be a nightmare. I am also concerned that the appropriate sound source material be the best one could get, and not streaming, regardless of popularity. Would you put 87 octane in your Porche or Corvette? I read about this being done for a $150K loud speaker and seems inappropriate for the quality of the speakers. Who does this for such high quality products??
I have had Tidal HiFi and I can tell you that the sound quality of it compared to the same CD disc, the stream is not the same. I have an over 4GHZ machine with a nearly 900MB download speed, and it was easy to pick out the CD.
It is sad that there is trouble in streaming and MQA land, but not surprised. The question we all ask is: How far does one need to go when most music engineering is only 4 out of 5 stars or less? Luckily many releases are better than that which helps.
I forgot to add that in heavy rotation is the Eva Cassiday/LSO engineering marvel that is great fun and sounds very good to me. In my DAW a nearly -70db noise floor, little or no compression and no peak limiting. Marvelous. A great system should love this. Mine now is a Schiit Asgard headphone amp; Project S2 DAC, and a pair of AKG K701 cans.
I always respect your comments, Jim. Nonetheless, in my system, the sound of files, whether stored on a NAS, internal SSD, or streamed from Tidal and Qobuz is virtually the same. It also tops CD. I haven't even listened to my dCS Rossini transport in over a year. And it is no slouch. No slouch at all.
Be well,
jason
You enjoy a very revealing system and I'm sure you are very happy with what you hear. Who couldn't be with the Wilson's at the base of it all. But, as we learned in the follow up with the MoJo Audio Mystique, there may be issues that are just hard to pin-point flaws in the sound. Some may even prefer it. THAT I WOULD NEVER ARGUE WITH. Maybe a system too revealing could be a curse?
I remember a decade old review of a respected engineer's CD player that was loved by a reviewer, but then found to be broken in the "Measurements Section". Did the reviewer's system or speakers cover up hearing the flaw?
I always now view any files in my DAW which not only has the wave form, but an EQ display out to at least 20khz, further for 24/192 files. It also has a spectral display and I can see what has been done in terms of compression and peak limiting. I don't master any of my work, but the clients and my wife who cares little about audio, can tell me if she hears a difference or not. Which one sounds better she can tell.
I can only report about what my tired, nearly 76 year old ears hear, but I can see, and hear some differences through my Spectrum high speed connections. I have also heard other reviewers say that some switches have added coloration to the sound of streaming. That determination might be beyond me. Maybe these new stand alone Music Servers are much better than a good computer?
Since various DACs sound different I remain unconvinced that streaming sounds the same as physical media from what I see. If material is transferred to a HD/server/NAS and the same DAC is used, THAT I can believe should be the same. I have no knowledge of what the streaming services "DO" to the files they store, and then, present to us, anymore that what the mastering engineer does to the mixed files that he chooses to "adjust" to make it "better?". I don't have his/her ears or audio systems to know what "better" really means today.
Now that I am recording again I am paying more attention to what I do and being retired, I have the time to take the time. Some of the recordings I do are audition tapes for music students to enter Grad school so there is some pressure for me to do the best I can with the gear I own, I do these recordings for free and love doing it for them.
I have an album by an artist I admire and the album was engineered by 5 different people and each track by them sounds different and one can see they are different in my DAW. There were recorded in respected studios, yet one track with orchestra and strings sounds more like a synth/string patch than real strings; where others sound as real as I have ever heard. I go back to some '60s Sinatra albums with great orchestrations, Ronstadt/Riddle's 3 big band albums; and the late Al Schmitt's work with big bands and Diana Krall. The Ronstadt albums have great HF energy, more than the Krall's done at Capitol. Mixing and mastering choices someone made.
I am now onto a new to-me artists where tracks 5-9 have much more HF energy than tracks 1-5. I can see that in my DAW. I can hear it as well as added clarity. No mastering credit is given so could it be two different people mastered their part of the tracks?
I also took a writer's advice on an old recording of a European concert by Oscar Peterson. It was for a radio broadcast so I was not expecting superb engineering. The acoustic bass sounded OK. The Drums sounded OK, but then Mr. Peterson on the piano came in the piano sound was nearly the worst I've heard on a commercial disc. Just about anyone with a pair of Shure SM57s over the felts could have done better than this. A tragedy as a potential great concert capture ruined for lack of better attention.
I am convinced that the sound we all seek is always going to be a mixed bag, that some in charge prefer a sound scape different than mine, much of it I do really like, but choices are made in all of this from recording, to streaming, to pressing, to mastering. Many hands in the soup.
All I am after is "real" as much as anyone can achieve it. With Mr. Atkinson's recordings I have studied them, re-read his liner notes over and over to learn, followed his issues with venues and gear placement with great interest to learn. I follow any video I can to see and hear the recording sessions and mic placements, including AL Schmitt's Big Band DVD, and Krall's Live in Paris DVD. There is always something for me to learn as to why things sound like they do. I especially learned much from the Michaelson's K622, JA, and the great Tony Faulkner. It all matters.
I would even bet that the sound differences from streamer brands is as different as the sounds from various DACs, and the improvements there in the last 10 years is remarkable. What I have enjoyed from streaming is to get to preview a reviewer's recommendation before I buy the physical copy, and now with the price of LPs that is a pretty important thing to do these days.
CDs played back on my Rossini are easily better than streaming and files played from the drive are better than those. I bought into streaming hook line and sinker a long time ago and wondered why I wasn't connecting with music.
You mean files played back from an external drive you've connected to the Rossini? I ask because the Rossini has no internal storage.
I don't know how you've implemented streaming. In my case, I convert ethernet to optical and then back to ethernet using a Sonore / Small Green Computer optical converter and an Uptone Audio etherRegen. Both contain the best-sounding Finisar SPFs that I could fine. (Andrew at Small Green Computer can help with this.) Both of those optical/ethernet converters receive power from linear power supplies. There is also an external clock on the etherRegen. That may be far more complex and costly than you or anyone wishes to do and/or is able to afford. (The least expensive part of the set-up is the optical cable.) But the end result is streaming sound that is virtually indistinguishable from files stored on a music server's SSD or on a SSD USB stick.
I am running directly from Nucleus Plus to the Rossini via Audioquest diamond. yes files on HD USB stick in the Rossini also sounds better. Streaming is complex and maybe this isn't the best way but honestly my CDs played back in my transport are vastly superior to streams or HD playback. Nucleus plus is out of the equation so maybe that whole unit is the weakness. I don't know but I actually just enjoy playing and owning the CD. I'd rather get one thing I like and learn it than jumping all over all the time. With streaming I don't think I sat and listened to a whole album in years. Now I look forward to buying the product and holding it in my hands. I feel like we have lost our way with the pride of ownership with streaming. Mine sounds way better so I'm pretty content but I have to think something is wrong. It's a thinner sound and just less life to the music. Vinyl is even at a whole other level above CD but that is another topic.
A few points that may have relevance:
1. The Nucleus + will sound much better if you use an LPS. Not all LPSs sound alike. For example, LPSs from Sonore and Nordost sound much better than the HDPlex. They're more transparent and convey more color. Which is not to say that good dedicated music servers from Innuos, Aurender, and Antipodes may ultimately give you better sound than a tweaked out Nucleus +. I'm using an Innuos Statement Next Gen right now.
Just be careful to ensure that, with an LPS, you use the right voltage and connector with the Nucleus +. Otherwise, you may kill the thing.
2. I expect you know that ethernet is the better-sounding input on the Rossini, and that, as a consequence, you're using AQ Diamond ethernet. Not all music servers allow you to choose between USB and ethernet outputs, but the Nucleus + does.
3. Are you using the same software in all cases? Mosaic has a different sound than Roon.
4. Have you upgraded to Rossini Apex? The sonic change will be far greater than any other change you can make to your network.
5. How you get your signal from your modem and router to the Rossini is critical. A dedicated ethernet switch, especially when powered by an external power supply, is vastly superior-sounding to the ports on a router. I use Nordost's and have not tried others. The Nordost Ethernet Switch is powered by their LPS. I also use ethernet to optical to ethernet to eliminate noise. Every one of these upgrades improves the sound of streaming.
6. The "feel it in your hands" reality is a different one than sound per se. If holding a CD or LP speaks to you, then it speaks to you. It speaks to me far, far less than it once did. Different strokes for different folks.
Deadlines prevent me from continuing. I hope I've been helpful.
jason
I might try an LPS for the Nucleus. I had good results getting one for my CD transport.
I was told to use the ethernet input so I never questioned it. I lived for quite a time with the Rossini streaming and only bought a lower cost CD transport to play a few CDs I could not play anywhere or stream them even. I was completely shocked by the sound compared to streaming. I was really missing out on a lot with streaming compared to playing the CD
I haven't messed around a lot with Mosaic, even playing a USB stick sounds pretty good but the interface to play it is very clunky and not a joy to use like Roon. I like the Roon program I mean you pretty much have to have it if you are going to be serious about keeping your music collection all together and it's mostly a joy to use though it sometimes develops a sickness and runs slow or acts up and then magically gets better
No I have not upgraded to Apex. In fact I had the clock and it's useless for my CD playback and I didn't hear much with it for streaming so I got rid of it. I'm a little skeptical of 9K for an upgrade seems pretty steep but I'll look into it more. I think your idea of a nice streamer might be a good way to go and just go AES into the Rossini then I don't have to even deal with any of the ethernet stuff. The switching and router interface is likely the cause of the lesser sound I get via streaming.
Thanks for all the advice.
If you have the $ for the Apex upgrade, do not pass it up. You will be astounded.
If the Rossini clock did not make an appreciable difference to your sound, then I'd look to your cables. Why? Because the Rossini clock is many times better than the Rossini's internal clock.
The Rossini's ethernet input is highly optimized. I do recommend it. Again, ethernet cables make an appreciable difference.
It's all a matter of time, money, and discrimination. In no particular order, unless money is a major concern. If it is, the order is clear. Rossini Apex will not shelter you from the cold.
jason
I should state that the Rossini clock is of no use with the SPDIF input I use for my CD transport and the CD transport sound so much better than streaming with or without the clock I figured I would put 7K back in my pocket. I kept having to go in and change a filter or I was getting digital artifacts with the clock in the circuit. You can't use SPDIF with it.
I was using Audioquest Diamond BNC cables for the clock so pretty good. I use a Synergistic Research Galileo SX on the output from my transport and that cable is definitely better than the AQ diamond, but diamond is still pretty good middle of the road cable.
I think maybe if I want to up my streaming game it's a PSU for the Nucleus first and foremost then look at the ethernet switch
I have heard other mixed reviews of the clock. some say huge upgrade others say they like it better without the clock. Rossini is a complicated beast when you look into all the filters and settings it can do. Makes my head spin. I like the CDs I have a stack sitting here and one thing for sure is, when I stream an album rarely do I make it through. When I get a CD I play it, learn it and enjoy the art and whole package as a statement as the artist intends. I add to my collection on Discogs, I put it on the shelf. I look at my shelves of LPs and CDs and makes me feel like I've really got something. I guess kind of like having a ton of books on kindle and none on the shelf, good comparison. I'll take the books on the shelf all day. A small hard drive just isn't the same.
I think I've adopted you.
There's only one thing I don't understand. If by SPDIF you mean RCA, there are RCA to BNC adapters. Nordost uses them regularly because they find a BNC cable with an adapter still sounds better than a cable with RCA terminations. Besides, if memory serves me correctly, you can just connect the clock to the Rossini if necessary. So I don't see the problem.
Anyway, yes, a good LPS or, if it sounds as you, Hybrid Power Supply for the Nucleus. Then use the $7000 for Apex. As for the filters, the suggestions in the Rossini manual work pretty well.
Hope to meet you at a show sometime. Munich, Santa Ana (T.H.E.), and Seattle (P
AF) coming up.
I mean when you use the spdif input on the Rossini the clock is of no use in fact you have to put the Rossini in a mode that takes the clock out of the loop to make it work without adding digital nasties. The BNC inputs for the clock are something else. So the clock is of no use when using my CD transport via the SPDIF input. CDs sounded so much better, I rarely stream for anything other than convenience so I got rid of the clock.
Thanks for all the advice, I'm going to be on the lookout for a LPS, or as you say maybe even a streamer from Aurilic might be better and get me away from the ethernet hub, just go wireless. seems like a waste because you are paying for a good streamer in the Rossini
I used to be a tidal hifi plus subscriber for two years but after my initial enthusiasm about mqa I now find sound quality seriously lacking compared to redbook cd or locally stored hi-res files (especially of the 24/192 pcm and 128+ dsd kind) let alone vinyl. Reportedly tidal is moving to lossless after mqa's bankruptcy so I'll be checking their progress sometime later.
I have used JRiver for DSD and found it very good, but here is my problem. I have had a number of USB playback devices with mic inputs for making videos and audio playback. None of them supported DSD, just PCM up to 24/192. DoP has never appealed to me as I love SACDs, but with no players under $1k now it is no wonder the market is slow for SACD except for high end audiophiles. Maybe Schitt will come to the rescue????
Luckily my 2007 Yamaha S1800 still plays like a champ. All of my Sony's have died the SACD playback death (4 of them), but still play 2496 pcm DVD-Vs. I had no interest in MQA regardless of the hype.
I am not about to jump into $2k plus streamer land at 75. It will be nice to see what else comes from the show.
To be more than 300k into a system only to have the next best thing come along. FOMO must be an expensive part of living (and selling point) at that level.
hello .. can i know the method by which the output impedance of the amplifier is measured and calculated? for amplifiers from this manufacturer, the advertising usually claims a damping factor of more than 10,000 in the audio frequency band, and this somehow does not compare with the measured output impedance of the amplifier
Thank you... And at what voltage and frequency is the measurement made at idle
?