Cute new schiit speaker amps

[bashbish]

I received my Rekkr this week and am pretty pleased with it. I have a McIntosh C27 pre-amp the requires an external amp to drive the headphones. It works like a charm and the amp barely gets warm. I also hooked the Rekkr up to a pair of Golden Ear BRX speakers that are supposed to be ~90db and my daughter told me to turn it down. Not a metric but a good sign. I do have a separate audiophile system for serious listening and wouldn't focus on this amp as an audiophile-level component or worry about cranking it to 11. It clearly fills specific needs.

 

[Deleted member 48726]

Dynamic range for different music-->

Quality speakers for classical music with high output/volume

Also,the number I would rely on is this: (taken from their site,note that this is short term at 2.3 meters) I didn't find peak power but you definetly need more than that even if you adjust your seat at this distance.

audiosciencereview.com

10 W ain't getting you far. Unless:

1. You are ok with not getting the full range sound IE lack of bass < 100 Hz
2. You don't listen to dynamic music
3. You sit right in front up close to the speakers

Power is cheap today. Have plenty and don't worry.

 

[staticV3]

10 W ain't getting you far. Unless:

1. You are ok with not getting the full range sound IE lack of bass < 100 Hz

Speakers react linearly to changes in power. Reducing power reduces the volume, but frequency response stays the same. You'll lose just as much bass <100Hz, as you'll lose mids and highs.
Unless you're talking about perceived loss in bass (IOS226)?

 

[Presb4]

Ok adding my 2 cents again on this bass vs. needed wattage subject. It depends.....
There are speakers that are designed to produce good low frequency bass with small drivers, ported, 1/4 wave horn, transmission line, ect. and then there are speakers that use a large woofer to generate the same low frequency bass.
The speaker that has a larger cone will need to move more air because it has a larger air piston, moving more air = more watts.
The speaker that generates the same bass note at the same db but with a smaller cone does not need the same power to do so, cuz its moving less air, smaller air piston. Because of this, one can not make a blanket statement that you need to have X watts of head room to produce good bass. It depends on the speaker design you have.

Now I do agree that if we are keeping all things equal, same box, same size cone, same amp, same room, same level (db) then the lower the frequency, the more power you will need, its dang near exponential in the amount of power you will need.

A great example of this can be seen in this video where they were testing subwoofers and which is more efficient a sealed box or a ported box. Subwoofer power needs, sealed vs ported. Not that my point hinges on ported vs sealed, but in this test you will see that when all things are equal, the lower the frequency the more power it takes to make the same db.

Now back again to the purpose of these small amps, in my opinion, are not designed to drive full range large speakers in medium or large rooms, they do not have the power to do that with most speaker designs. But if used as intended, they work great for small rooms or for desktop applications at modest db levels.

 

[Hatto]

Dynamic range for different music-->

Quality speakers for classical music with high output/volume

Also,the number I would rely on is this: (taken from their site,note that this is short term at 2.3 meters) I didn't find peak power but you definetly need more than that even if you adjust your seat at this distance.

audiosciencereview.com

10 W ain't getting you far. Unless:

1. You are ok with not getting the full range sound IE lack of bass < 100 Hz
2. You don't listen to dynamic music
3. You sit right in front up close to the speakers

Power is cheap today. Have plenty and don't worry.

From the very link you provided:
"Dynamic range in jazz is generally varied from 13dB to 23dB"
"The same study found that recorded classical music typically offers between 32dB of dynamic range"

32dB dynamic range means approx. 16dB difference between peak and mean. A stereo pair of speakers with 88dB/W/m efficiency rating can provide 96dB SPL peak at 6 ft listening distance WITHOUT ANY ROOM EFFECT. The actual peak output would be even higher in a confined space, but let's ignore that. 96dB peak means one can listen music with 32dB dynamic range at 80dB SPL average. In reality a good amplifier can provide peak values much higher than its rated power, which allows it to accommodate instantaneous peaks even higher than 96dB. Adding that to the increased SPL due to room effect, the actual SPL would probably be even higher than 80dB.

Please do CALCULATE the specific amount of reduction under 100Hz with 10W amplifier power with any 4-6 inch driver so we can all learn.

 

[Hatto]

Ok adding my 2 cents again on this bass vs. needed wattage subject. It depends.....
There are speakers that are designed to produce good low frequency bass with small drivers, ported, 1/4 wave horn, transmission line, ect. and then there are speakers that use a large woofer to generate the same low frequency bass.
The speaker that has a larger cone will need to move more air because it has a larger air piston, moving more air = more watts.
The speaker that generates the same bass note at the same db but with a smaller cone does not need the same power to do so, cuz its moving less air, smaller air piston. Because of this, one can not make a blanket statement that you need to have X watts of head room to produce good bass. It depends on the speaker design you have.

Now I do agree that if we are keeping all things equal, same box, same size cone, same amp, same room, same level (db) then the lower the frequency, the more power you will need, its dang near exponential in the amount of power you will need.

A great example of this can be seen in this video where they were testing subwoofers and which is more efficient a sealed box or a ported box. Subwoofer power needs, sealed vs ported. Not that my point hinges on ported vs sealed, but in this test you will see that when all things are equal, the lower the frequency the more power it takes to make the same db.

Now back again to the purpose of these small amps, in my opinion, are not designed to drive full range large speakers in medium or large rooms, they do not have the power to do that with most speaker designs. But if used as intended, they work great for small rooms or for desktop applications at modest db levels.

Driving dedicated subwoofers down to 20Hz with 10-12" drivers is a specific case. You won't experience any loss of fidelity at regular listening volumes with general spectrum stereo speakers due to lack of power.

Again, if someone can prove (with calculated numbers based on actual data) that loss of fidelity happens under SPL level of any speaker's rated efficiency up to 2 meters with 10W amplifier power I'd be happy to learn from it.

 

[Presb4]

From the very link you provided:
"Dynamic range in jazz is generally varied from 13dB to 23dB"
"The same study found that recorded classical music typically offers between 32dB of dynamic range"

32dB dynamic range means approx. 16dB difference between peak and mean. A stereo pair of speakers with 88dB/W/m efficiency rating can provide 96dB SPL peak at 6 ft listening distance WITHOUT ANY ROOM EFFECT. The actual peak output would be even higher in a confined space, but let's ignore that. 96dB peak means one can listen music with 32dB dynamic range at 80dB SPL average. In reality a good amplifier can provide peak values much higher than its rated power, which allows it to accommodate instantaneous peaks even higher than 96dB. Adding that to the increased SPL due to room effect, the actual SPL would probably be even higher than 80dB.

Please do CALCULATE the specific amount of reduction under 100Hz with 10W amplifier power with any 4-6 inch driver so we can all learn.

I don't have the measurements for a 4 to 6 inch driver. But in the video I posted they show the stats for a 12" woofer, is that not proof enough? In that video they showed that the wattage needed for the same driver to produce the same db at different frequencies would require the following (pulled from the sealed box data).
50hz needed 300 watts, 45hz needed 443 watts, 40hz needed 540 watts and 35hz needed 638 watts.

 

[darmok]

There's a lot of arguing about how much power you need in this thread but not a lot of empiricism being applied to the question. No transient is going to be louder than a pure tone at 0db, so determining whether an amp has "enough" power is a matter of measurement and listening. Let's take the Rekkr: I'm running the it into a pair of Jamo S801s I had lying around from another project, and while there's no measured impedance for this I'm going to assume it's similar to the S803 that Erin previously measured. The minimum EPDR on the S803 is 4.8Ω, so to be on the safe side I'll use the 4Ω rating of 3W per channel, or 3.46Vrms. The Rekkr has a gain of 4, so that works out to .87Vrms input sensitivity.

After turning off the Rekkr (very important step) I played a 1KHz tone at 0db from my source and adjusted my preamp until it was just below .87Vrms output on my multimeter. Now I could listen to a few tracks and really see if the volume was sufficient.

• Future Sound of London, Yage 2019: WAY too loud for nearfield listening, or anywhere in my office to be honest.
• Keith Jarret / Gary Peacock / Jack DeJohnette, Always Let Me Go: louder than I'd like for nearfield, pretty good at the other end of the room.
• ELP, Brain Salad Surgery (2014 remaster): initially sounded just about right in nearfield use, but after leaving it on for a few minutes I found myself absentmindedly reaching for the volume control to turn it down.
• Steve Reich, Music for 18 Musicians (original ECM recording): WAY too loud.
• Shostakovich, Symphony 14, Bernard Haitink / Decca CD: another one that initially sounded just about right, but ended up way too loud at the start of the third movement.

I then turned the volume on the preamp down to a more comfortable nearfield listening level and measured .42Vrms on a pure tone. Into 4Ω, that's about 700mW.

Your mileage, ears, and music may vary, but I'm satisfied that with bookshelf speakers of average sensitivity and a minimum EPDR of 4Ω or more, Rekkr has plenty of power for nearfield music listening. You don't have to take my word for it, though. If you have an amp with a known gain, a pair of speakers that you'd like to use in nearfield, and a multimeter, it's easy enough to perform the same experiment. Remember that if you're using EQ, you should measure at the frequency with the highest gain, or just turn off the EQ for the measurement as long as it's digital or otherwise has no gain associated with it.

So what does more power get you? The ability to drive less sensitive speakers, more power for farfield listening in larger rooms, the ability to use EQ to increase bass output without affecting the volume of the mids and highs, and better volume for movies and TV shows, which tend to have much greater dynamic range. While 3W is plenty for music in my setup, it's just adequate for watching movies. I don't tend to do that at my desk, so it's not of great concern to me, but it might be for you. Even the Gjallarhorn's 15W isn't enough here; after putting my preamp into high gain and adjusting volume until the average quieter dialogue in a movie was uncomfortably loud, I ended up with 7Vrms output from the preamp, which would work out to 28Vrms with a gain of 4 or roughly 200W into 4Ω. If you want a Schiit amp to watch movies at movie theater volumes at your desk, Vidar is your amp. For music, gaming, and typical YouTube videos, Rekkr is plenty for me.

 

[darmok]

I don't have the measurements for a 4 to 6 inch driver. But in the video I posted they show the stats for a 12" woofer, is that not proof enough? In that video they showed that the wattage needed for the same driver to produce the same db at different frequencies would require the following (pulled from the sealed box data).
50hz needed 300 watts, 45hz needed 443 watts, 40hz needed 540 watts and 35hz needed 638 watts.

This isn't relevant unless you're trying to EQ your bookshelf or floorstanding speakers into giving you subwoofer-like bass. Without EQ, the output of your typical two-way speaker takes a significant dive below 50 or 60Hz (referenced to constant voltage) and there's nothing that amplifier headroom can do to fix that. With EQ, you're likely to end up with enough distortion that worrying about amplifier quality will become irrelevant anyway. Impedance is typically lowest in the lowest frequencies, so this is where your greatest power draw will be, but as long as your amp can supply what your speakers draw at its output voltage and with minimal distortion, it doesn't really matter how much extra juice you have on tap.

Remember that amplifiers are voltage amplifiers until they run out of current. Having more current available than your speakers draw is like plugging a 150mA LED light into a 20A outlet. There's no harm in doing so, but the light's not going to get any brighter because of it.

 

[Hatto]

I don't have the measurements for a 4 to 6 inch driver. But in the video I posted they show the stats for a 12" woofer, is that not proof enough? In that video they showed that the wattage needed for the same driver to produce the same db at different frequencies would require the following (pulled from the sealed box data).
50hz needed 300 watts, 45hz needed 443 watts, 40hz needed 540 watts and 35hz needed 638 watts.
View attachment 273178

Thank you for sharing but the test you shared is not relevant. Most general purpose stereo speakers don't even go below 50-60Hz to begin with. Do you have similar data (or calculations) showing the numerical values of power gradient over the 50Hz-15kHz spectrum at reasonable, practical listening levels?

 

[Asyrin]

OSHA says 0 minutes per day is the safe level of spl greater than 115...

Turn your music down.

I don't have the measurements for a 4 to 6 inch driver. But in the video I posted they show the stats for a 12" woofer, is that not proof enough? In that video they showed that the wattage needed for the same driver to produce the same db at different frequencies would require the following (pulled from the sealed box data).
50hz needed 300 watts, 45hz needed 443 watts, 40hz needed 540 watts and 35hz needed 638 watts.
View attachment 273178

 

[JustJones]

System Performance Calculations

Will my audio system produce audible noise? Will my audio system produce audible distortion? How will my audio components work together as a system? How loud will my audio system play? Use Benchmark's online audio calculators to find answers! If we know the output power of an amplifier, as well...

benchmarkmedia.com

 

[NTK]

Thank you for sharing but the test you shared is not relevant. Most general purpose stereo speakers don't even go below 50-60Hz to begin with. Do you have similar data (or calculations) showing the numerical values of power gradient over the 50Hz-15kHz spectrum at reasonable, practical listening levels?

It is the source content that matters. If the music has contents at <50 Hz (or whatever), the amplifier will amplify it and uses up its capacity regardless of whether the speaker will turn only it into heat.

 

[mhardy6647]

It is the source content that matters. The amplifier will amplify it and uses up its capacity regardless of whether the speaker will turn only it into heat.

Yes but the converse (so to speak) would also be true. Not all loudspeakers are as flagrantly electrically inefficient as today's darlings at 85-ish dB per watt (let's even say "per 2.83 V" to allow for the currently fashionable low to dangerously low impedance) @ 1 meter sensitivity.

No -- no they're not.

 

[NTK]

Yes but the converse (so to speak) would also be true. Not all loudspeakers are as flagrantly electrically inefficient as today's 80-ish dB per watt @ 1 meter (and hard to drive) darlings.

No -- no they're not.

Desktop speakers? Hoffman's iron law?

 

[mhardy6647]

Small amplifiers require large loudspeakers. No reason to use fleapower with desktop. Hoffman's iron law indeed.
I use 3.5 watt amplifiers but my loudspeakers are Altec Voice of the Theater sized -- and dynamic. Very dynamic.

 

[CDMC]

Ok adding my 2 cents again on this bass vs. needed wattage subject. It depends.....
There are speakers that are designed to produce good low frequency bass with small drivers, ported, 1/4 wave horn, transmission line, ect. and then there are speakers that use a large woofer to generate the same low frequency bass.
The speaker that has a larger cone will need to move more air because it has a larger air piston, moving more air = more watts.
The speaker that generates the same bass note at the same db but with a smaller cone does not need the same power to do so, cuz its moving less air, smaller air piston. Because of this, one can not make a blanket statement that you need to have X watts of head room to produce good bass. It depends on the speaker design you have.

Now I do agree that if we are keeping all things equal, same box, same size cone, same amp, same room, same level (db) then the lower the frequency, the more power you will need, its dang near exponential in the amount of power you will need.

A great example of this can be seen in this video where they were testing subwoofers and which is more efficient a sealed box or a ported box. Subwoofer power needs, sealed vs ported. Not that my point hinges on ported vs sealed, but in this test you will see that when all things are equal, the lower the frequency the more power it takes to make the same db.

Now back again to the purpose of these small amps, in my opinion, are not designed to drive full range large speakers in medium or large rooms, they do not have the power to do that with most speaker designs. But if used as intended, they work great for small rooms or for desktop applications at modest db levels.

Sorry, but you are incorrect. Larger drivers are not inherently less efficient, driver efficiency is a function of bandwidth, magnet design, cone weight, and other factors. Bass output is a function of driver sensitivity, enclosure design, enclosure size, bass extension (part of design), and power input. Take two drivers, one 8”, one 15”, with the same thiel small parameters, use the same enclosure design, sized appropriately for each driver, and both will be equally efficient, and have the same bass extension. The difference is the larger driver will be capable of taking more power and putting out a higher spl.

Spend some time reading about thiel small and Hoffman’s iron law. The basic physics of drivers and how they perform was established 70 years ago.

 

[Deleted member 48726]

Driving dedicated subwoofers down to 20Hz with 10-12" drivers is a specific case. You won't experience any loss of fidelity at regular listening volumes with general spectrum stereo speakers due to lack of power.

Again, if someone can prove (with calculated numbers based on actual data) that loss of fidelity happens under SPL level of any speaker's rated efficiency up to 2 meters with 10W amplifier power I'd be happy to learn from it.

Dude, all the info you need are in this thread and more. I will not be the one to spoon-feed you anymore but I will comment when you give people advice that contradicts good reason.
I guess you are not able to comprehend information that disturbs your point of view.

 

[Hatto]

Dude, all the info you need are in this thread and more. I will not be the one to spoon-feed you anymore but I will comment when you give people advice that contradicts good reason.
I guess you are not able to comprehend information that disturbs your point of view.

I don't have a "point of view", I'm in search of facts using objective, mathematical results.

All the "information" that is presented in the links you provided are either subjective opinions, or numerical data (which I have referenced) that confirms the mathematical relations I've presented over and over and over again.

Besides, you're the one with the claim, so the burden of proof falls on you through of calculations and objective evidence. I'm just one of those who are not convinced based in absence of such.

Talking about "spoon feeding" as if you have presented any calculations yourself. If you have the capacity to calculate the conditions under which "loss of fidelity" occurs due to "lack of amplifier power" under normal, reasonable listening conditions for a stereo pair of over-the-average rated efficiency (88dB/W/m) speakers, I would be happy to learn.

And if you're incapable to support your claim through basic calculations or unwilling to go through the effort, that is fine too; just don't hide behind excuses.

 

[NTK]

Instead of using a single frequency sine wave, here is what you'll get with a signal that is representative of the characteristics of music -- M-Noise, AES Standard AES75-2022.

AES Standard » AES75-2023: AES standard for acoustics — Measuring loudspeaker maximum linear sound levels using noise

This standard details a procedure for measuring maximum linear sound levels of a loudspeaker system or driver using a test signal called Music-Noise. In order to measure maximum linear sound levels meaningfully and repeatably, a signal is required whose RMS and peak levels as functions of...

www.aes.org

M-Noise

M-Noise is a new test signal that promotes standardized measurement of a loudspeaker system’s maximum linear output.

m-noise.org

M-Noise crest factor = 7.832 (= 17.9 dB). See below (reference):

Assuming the short term transient power of the Schiit Rekkr is 1.5x its rated output, its clipping voltage is 6.928 V.

Rated output power (Schiit Rekkr) = 2 W @ 8 ohm​

V_rms @ rated power = sqrt(2 * 8) = 4 V​

V_pk @ rated power = sqrt(2) * V_rms = 5.657 V​

​

Assuming a short term power headroom of 1.5x rated power​

Clipping voltage = V_pk * sqrt(1.5) = 6.928 V​

With M-Noise, for a speaker with 88 dB SPL sensitivity, that means a maximum of 77.9 dB SPL, 1 m, free field, before the on-set of clipping.

M-Noise V_rms = V_pk / Crest Factor = 6.928 / 7.832 = 0.8846 V​

M-Noise SPL at clipping = 20 log10(0.8846/2.83) + 88 = 77.9 dB​

See also Charles Sprinkle's comments on amplifier power rating:

Kali IN-5 Studio Monitor Review

Finally saw it. Looks like we finally got a good and "cheap" monitor. H2 is a bit high, but who cares, H3 stays under 0.5% at 96 dB and under 0.2~0.3% after 500 Hz; not even changing with SPL! And as already said, the diffraction is moved in a much more benign area and with a lower level. Will...

www.audiosciencereview.com

Excerpt:

...​

So which way is the right way to measure power? I have something to say about that. The traditional way of rating "power" as V^2/R with sine waves is in my opinion complete nonsense. Power amplifiers don't amplify power. They amplify voltage. People don't hear watts. They hear SPL. We provide output "power" ratings as a reference, and yes, they are honestly measured and specified as described above. But I hope we all understand that actual power produced into a reactive load with complex impedance using real music or program material is going to be substantially less than headline "power" ratings.​

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