you should be fine with your limited listening levels and expectations but your speakers with dual 12" woofers deserve so much more and would reward you immensely.
100 watts enough?
Hi all. I'm contemplating purchasing a CH Precision A1 and I don't know if it will drive my speakers adequately. I have EgglestonWorks Andra III speakers which are 88db efficient (impedance 8 ohms nominal, 6 ohms minimal). I have a 30x20ft room and I sit about 14ft from the speakers. I live in a condo and have almost nothing between me and my neighbor so I don't ever crank up the volume. I use a VAC Renaissance preamp that I almost never crank past 9 o'clock. The Andra III is a speaker that likes lots of power to open up. So what do you think?
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These massive 25 watt only into 8ohm ML2 monoblocks will drive a pair of Wilson Alexia’s (hardest speaker known to drive in the bass 0.9ohm ) magnificently to a certain loudness because they can do big current. They almost double their wattage for each halving of impedance all the way down to 1ohm-200W!!! https://img.usaudiomart.com/uploads/large/2229206-5c605986-mark-levinson-ml2.jpg As you can see wattage is not everything! Cheers George |
No one has posted the combined impedance/-phase graph on these, so here it is. Even the EPDR loading will be easy. https://www.stereophile.com/images/archivesart/Eggfig01.jpg As you can see easy load, even tubes from the 4ohm tap will sound great into them. Cheers George |
it is of course in the eye of the beholder, but i have considered the following over time as reasonable descriptions below 86 db / w / m -- inefficient 87-89 db -- moderately efficient 90-92 db -- efficient 93 db and up -- very efficient impedance and nature of reactivity of the speaker load figures in too ( eg -- an 'efficient' load of 90 db at 3.5 ohms impedance still may not be easy for certain amps to drive)... but based on the simple measure of db/w/m above that is a simplistic and proper ranging imo |
Well, it certainly has a unique crossover and driver configuration. Based on the Stereophile measurements, the absolute minimum impedance is 4 Ohms around 20 Hz, and higher elsewhere. I would say a modest amplifier of 100 Watts should be plenty in a modest room, and that these speakers are good candidates for tube amps as well. https://www.stereophile.com/content/egglestonworks-andra-loudspeaker-measurements |
@tarheelneil51, The listening distance (4 meters) factor was accounted for in kijanki’s calculations. See his post above. ’Based upon the information supplied by the OP, I would go with quality over quantity.’, Per @onhwy61. Yep, this is my point. A very (Perhaps ultra) high quality solid state amplifier driving speakers that for the most part have a speaker impedance of 10 ohm or above. Dip no lower than 4 ohm in the lower bass. This is not a challenging load for the very robust designed CH Precision A1 amplifier (Substantial power supply and capacitance reserve). Quality indeed. Charles |
If the listener considers 80db loud, then CH 100 watt amp should work. The listener should be able to achieve 98dB peaks at the listening position before the amp exceeds its rated power. The Egglestons are not a demanding load and the CH is a robust design. Based upon the information supplied by the OP, I would go with quality over quantity. |
charles1dad7,812 posts07-03-2021 8:41pmFrom John Atkinson/Stereophile, "The EgglestonWorks Andra is moderately sensitive, my estimated 87dB/ ~~~~~~~~~~~~~~~~~~~~ Sorry to disagree with John Atkinson @ Sterophile But I will 87db, ~~MODERATELY~~ sensitive?? The TRUTH is 87db = IN-Efficient IOW In/UN Effective. = Blood sucking speakers. Below 91db = INefficient/low sensitivity. = all xover box designs Inefficient. Lets be honest around here , would we please. |
When reading all the comments referring to SPL measurements, keep in mind that SPL is referenced at 1m from the speaker, that you are 14 feet (just over 4 meters), and that SPL decreases -6bB for every doubling of distance. That means that at your listening position, your SPL is about 13 dB lower than at the 1m reading. BUT, a doubling in wattage only achieves a +3bB increase in volume. So, at your 14 foot listening distance, you will need almost 20 times the watts as needed at 1m. Also, the more watts your amp has, the more headroom, and that allows the amp to stay within the linear portion of it. ( Depending on design, an amp is only linear for maybe the first 50-75% of it's power rating. The closer you are to it's rating, the less linear it gets, and ideally, you want to stay in that linear range). Because of all of this, get as much wattage as you can afford, The more headroom you have, the better. |
the OP can leapfrog half of audiogon with purchase and use of a decent SPL meter….. or better yet RTA w calibrated mic. I would say the CH is going to kick some A @charles1dad thank you ! the guy who designed the Treo feels same way. To be fair the RM-9 amp also designed by a genius - Roger Modjeski - RIP. Having said all that my reference system is 1.2 Kw a side….but it’s not a condo… isnt it wonderful we all have choices |
@unsound I hear you. I’m just basing it the OP suggesting his listening levels are modest. "I don’t ever crank it up". OP hasn’t chimed in to say what exactly those listening levels are in db for a better understanding. Modest levels to me would be mid 60s to mid 70s db C-weighted. In which case he’d be using only small fractions of a single watt. 10 watts gets him 92 db SPL. Well an interesting topic nonetheless. @unsound I appreciate your thoughts. Charles |
From John Atkinson/Stereophile, "The EgglestonWorks Andra is moderately sensitive, my estimated 87dB/2.83V/m (B-weighted) reading agreeing with the specified figure. Its impedance plot (fig.1) suggests that the speaker appears to be an easy load for an amplifier to drive, the magnitude dropping below 10 ohms only in the high treble and below 130Hz, and the phase angle generally remaining low. However, it does reach 4 ohms in the low bass, around the tuning of the twin ports. There is a very slight wrinkle in the impedance traces between 300 and 400Hz, this generally indicative of a cabinet resonance of some kind. However, as might be expected from its massively constructed cabinet, the Andra is impressively inert. About the only resonant mode I could find was on the woofer enclosure wall (fig.2) at 350Hz. This is well down in level, however." Given this assessment coupled with the OP's stated "neighbors" situation it seems that the CH Precision 100 watt amplifier is far more than adequate . I guess I'm missing the rationale of why a more powerful amplifier is advantageous. It appears that this amplifier would coast driving the "easy load" (Atkinson's words) Andras to suit the OP's circumstances. Charles |
@unsound @charles1dad Just for reference, here is a link to loudness levels that studios are recommended to calibrate to when monitoring. The relevant table is ’Room size vs Reference Level’ all the way at the bottom. Note that for the largest space, the recommendation is 83 dB SPL (C weighted). This is measured using pink noise with a single speaker. Subtract 3 dB if playing the pink noise through two speakers. Another guidepost could be the THX Reference Level. This is set to 85 dB SPL (C) at the listening position as measured with pink noise. The equipment should be able to handle 20 dB peaks. So if you’ve been to a THX certified cinema, you’ll have a sense of how loud that is. In any case, I recommend getting an SPL meter and measuring yourself. You might come away surprised. |
I have to agree with those suggesting powerful amps. You want more than just enough, you want a high current amp. I would also recommend the Pass x350.8. I owned an x350 for fifteen years. Tremendous current, and it should make your speakers sound there best at low volumes as well. The VAC preamp sounds like an excellent match. |
charles1dad7,807 posts07-03-2021 9:06am@unsound wrote, ’Many amp designers suggest that amplifiers are typically at their most linear when operating at about 20% of their output ~~~~~~~~~~~~~~~~~~~ It is true the lower the gain on the linestage vol, the sweeter/cleaner the sound. But who here listens at a whisper. So 9oclock - 10oclock is ideal gain on vol. Over 10oclock you are adding to distortion, making 85db max on vol level. 90db, yuckkk, tahts too LOUD mouth. I listen at 70db near field. If 70, most likely 60 I am using no more than say 15 watts of the Defy 7's 100 watts. |
Hi @unsound, I get your point about loud volume levels and certainly it is subjective amongst respective listeners and their perception of such. Given the OP’s stated condo listening limitations/situation I’m guessing (And could be wrong) that 92 db SPL would be pretty loud relatively speaking. Charles |
@charles1dad, I haven't recommended higher powered amplification here. I agree with most of yours and Kijanki's posts, though I don't think 92 dB is all that loud, and I think the OPs rather large room is a consideration. IMHO, while 100 dB is most certainly verging on the loud side; 105-115 dB peaks are LOUD. |
@unsound wrote, ’Many amp designers suggest that amplifiers are typically at their most linear when operating at about 20% of their output and further suggest having about 80% headroom.’ This seems very logical. 20% = 20 watts from the CH Precision amplifier. Kijanki calculated based on robal’s seating distance from his speakers (Accurately in my opinion) 1 watt will provide 82 db SPL and 10 watts will provide 92 db SPL So definitely not exceeding the range of desired amplifier output linearity. 92 db is loud (Assuming no hearing deficits) and probably well above robal’s listening levels in his condo environment (Achieved with only 10 watts). CH Precision amplifier is providing 100 watts of very high quality. I don’t see the rationale for recommending higher power amplifiers for robal’s stated needs and circumstances. His speakers are 6 ohm impedance (Minimal) so they are not demanding of high current capability amplifiers. Charles |
You can also plug in your numbers into this calculator (Amplifier Power Required): https://www.crownaudio.com/en/tools/calculators It would be more accurate if you have an SPL meter but I reckon that most people self-select volume at around 71-74 dB continuous. This is what I call comfortably loud. If you listen at 71 dB, the amp wouldn’t even leave its continuous power range until a peak greater than 24 dB. That level of dynamics would cover large symphonic works, so the amp would be good for basically all music. |
It is a fairly large space to fill, on the other hand you are not typically seeking high volume levels. Many amp designers suggest that amplifiers are typically at their most linear when operating at about 20% of their output and further suggest having about 80% headroom above that. Ideally you could try it out with a return option. |
@robal The VAC preamp has a lot of gain (almost too much), which is why I can’t go past 9-10 o’clock on most recordings. don’t conflate preamp output voltage with receiving power amplifier power/capability frequent noob mistake... often with unfortunate consequences just because the gas pedal in car a is more sensitive than car b doesn’t make it more powerful |
Oh, I'd like to hear them, where do you live? Happily, your speakers were designed to allow bi-wiring. I'm thinking you will be just fine now, and if you ever move, want/need more volume, you could simply add a second amp, also designed for biamp/bridging, https://www.ch-precision.com/product/a1-two-channel-power-amplifier/ two = 200 wpc, OR, depending on your preamp/future crossover simply add a less costly separate amp dedicated to the woofers, keep this amp for the more important tweeters/midrange. http://egglestonworks.com/products/the-andra-iii/ BI– Amplification / BI Wiring Due to the unique crossover configuration of our loudspeakers, advantages of biamping and bi-wiring are maximized. We supply the Andra III with two sets of binding posts to allow for bi-wiring or bi-amping. The top set of binding posts drive the tweeter and midrange, and the bottom binding posts drive the woofer section. |
200W rms, no less. Sure a small condo, 100W will be “enough” the 200wpc, or 300WPC, will sound much more effortless, in every aspect of your listening, midrange, bass, highs, crescendo s’ etc etc. I learned my lesson a LOOOOONNNNGG time ago, when it comes to amplifiers, get 200-250W high current, or 300WPC amp. Minimum. Down the road, you will think back to that arctic.......whatever name he was, and silently say under muddled breath “thanks dude”. Been through several receivers, amplifiers, past 30 years, best were/are the amps with a minimum of 250wpc. Or try some wall treatments, expensive, but if they work, and allow you to get some volume,.....give it a try. We visit a condo in the Florida gulf, and I moved in a small stereo, some small Polk audio towers, Yamaha receiver, Sony 5cd carousel the polks look like the monitor 60, but I think older version. from after 2009 I think?The people in our condo are all old and have nothing to do except complain and cause problems. Check out eBay, I found a 3 pack of construction Noise cds. I love them, saws, hammering,, general talk, with dropping wood , metal grinding, glass breaking, they are great. The nosy neighbors called the accociation on me, because they didn’t see and construction permits on my door, yes, they came ,looked, and called and ratted us. So I play those cds on repeat, from 8am til 5 pm when we leave for the day. p anyway, if and when you move, or are able to play a little louder, you will be thankful you have the power! |
I think you’ll be sorry. I’ve tried 100, 150, 200 watts, and it took a Pass X250 to wake my Aerial Acoustics 7B’s. Sure the other amps could drive them but I had to crank it to get them to sing and then I felt the amps were still struggling a little. With the bigger Pass, even at lower volumes which I tend to play most often, my system sounds great. With the other lower powered amps, listening to lower volume wasn’t at all enjoyable. Would love to try a Pass X350.8 in my system. |
