How to calculate/know if a particular Amp / Speaker combination is fitting from a power/wattage perspective

[rubin]

Hi guys,

So I would like to know how you calculate if a given pair of speakers "fit well" with a given amp. I'm looking to buy a Topping D90SE, a Benchmark AHB2 and a pair of Revel F226BE's and would like to know how others here would (for example) determine if one AHB2 is "good enough" or if one would consider two of them. I'm especially interested in how the formula works!

Kind regards,

Rubin.

PS: Note that I'm not (yet?) thinking about buying a pre-amp since I don't think it's neccessary. Please correct me if wrong or if insightful opinion to share.

 

[abdo123]

Here you go: https://www.crownaudio.com/en-US/tools/calculators#amp_power_required

Enjoy!

 

[rubin]

Alright, that was super helpful. I'm pretty confident that I can run these with a single AHB2. I've been reading the excellent review of the Revel F226BE's on this site and was wondering about this comment:

"The minimum impedance dips to about 3.7 Ohms around 200Hz and again at approximately 50Hz. While the specification states the nominal impedance is 8 Ohm, the data shows the midbass-to-low-midrange impedance is closer to an overall nominal impedance at about 4 Ohms. A standard AVR would not be recommend for powering these speakers. A separate amplifier is recommended to drive this speaker to typical playback volumes."

What is meant with "A standard AVR" here? Does the above mean that I should think about these speakers as 4 Ohms even though the manual specifies 8 Ohm nominal?

The Benchmark AHB2 does 2x100W at 8 Ohms and 2x190 at 4 Ohms.

 

[Kal Rubinson]

What is meant with "A standard AVR" here?

A standard AVR would be a product from Marantz, Denon, Yamaha, etc.

Does the above mean that I should think about these speakers as 4 Ohms even though the manual specifies 8 Ohm nominal?

Possibly but the AHB2 is comfortable with that.

 

[Trouble Maker]

Devils advocate, what does the AHB2 (realistically) get you that a Hypex NC252MP doesn't? You could get more power in an NC502MP for about 1/5 of the price of the AHB2. You're money and there's little way to find any fault with the AHB2 aside from price, which still seems pretty reasonable considering the market and the performance.

NC252MP from our own @Buckeye Amps
https://www.audiosciencereview.com/...amplifier-builder-line-up-announcement.16835/
https://www.audiosciencereview.com/forum/index.php?threads/buckeye-6-channel-amplifier-review.18579/
VS
AHB2 https://www.audiosciencereview.com/...-and-measurements-of-benchmark-ahb2-amp.7628/

 

[Spkrdctr]

You have the easy answer. You want an amp that is rated for 4 ohms. That is it. Nice an easy. Many, many amps are rated for 4 ohms. Class D would be a GREAT idea for you. Good Luck!

 

[Kal Rubinson]

You are a trouble-maker. Let me give you three answers and you can run with any of them.
1. Technical/objective: If you look at the specs/measurement, the AHB2 outperforms any of the Class D amp except on pure power output and that is irrelevant if the AHB2 power output is suitable for your particular application.
2. Subjective: The AHB2 sounds better (cleaner, clearer, purer, etc.) than any Class D amp that I have auditioned but that is based on my system, my ears and my personal known-and-unknown biases. I also own Class D amps (NAD C298s) and could live happily with them.........if necessary.
3. Practical: Whether or not you will hear (or care about) any subjective differences is possible but unlikely.

 

[Spkrdctr]

You are a trouble-maker. Let me give you three answers and you can run with any of them.
1. Technical/objective: If you look at the specs/measurement, the AHB2 outperforms any of the Class D amp except on pure power output and that is irrelevant if the AHB2 power output is suitable for your particular application.
2. Subjective: The AHB2 sounds better (cleaner, clearer, purer, etc.) than any Class D amp that I have auditioned but that is based on my system, my ears and my personal known-and-unknown biases. I also own Class D amps (NAD C298s) and could live happily with them.........if necessary.
3. Practical: Whether or not you will hear (or care about) any subjective differences is possible but unlikely.

Kal, that is the politest public spanking I have had in years! My main point is any 4 ohm rated amp should be fine for him. Of course, that does nothing to trim down the huge amount of 4ohm rated amps he has to pick from!

 

[abdo123]

Alright, that was super helpful. I'm pretty confident that I can run these with a single AHB2. I've been reading the excellent review of the Revel F226BE's on this site and was wondering about this comment:

"The minimum impedance dips to about 3.7 Ohms around 200Hz and again at approximately 50Hz. While the specification states the nominal impedance is 8 Ohm, the data shows the midbass-to-low-midrange impedance is closer to an overall nominal impedance at about 4 Ohms. A standard AVR would not be recommend for powering these speakers. A separate amplifier is recommended to drive this speaker to typical playback volumes."

What is meant with "A standard AVR" here? Does the above mean that I should think about these speakers as 4 Ohms even though the manual specifies 8 Ohm nominal?

The Benchmark AHB2 does 2x100W at 8 Ohms and 2x190 at 4 Ohms.

I would say 3.7 Ohms is fine, if it dips below 3 Ohms i would be concerned. and even then the ABH2 should be able to drive anything.

 

[Kal Rubinson]

Kal, that is the politest public spanking I have had in years! My main point is any 4 ohm rated amp should be fine for him. Of course, that does nothing to trim down the huge amount of 4ohm rated amps he has to pick from!

I was not aiming at you. I was aiming at the self-identified "Trouble Maker."

 

[Trouble Maker]

Just trying to offer alternative ideas. I'll definitely defer to your expertise and experience, especially on point #2 @Kal Rubinson

 

[Rufus T. Firefly]

Hi guys,

So I would like to know how you calculate if a given pair of speakers "fit well" with a given amp. I'm looking to buy a Topping D90SE, a Benchmark AHB2 and a pair of Revel F226BE's and would like to know how others here would (for example) determine if one AHB2 is "good enough" or if one would consider two of them. I'm especially interested in how the formula works!

Kind regards,

Rubin.

PS: Note that I'm not (yet?) thinking about buying a pre-amp since I don't think it's neccessary. Please correct me if wrong or if insightful opinion to share.

I'm also looking at this combo sans speakers. Here are a couple things I have noticed that you may not have thought about, not that they are deal breakers. I don't believe the Topping gear has an out for a 12 volt trigger (meaning you'd have to manually turn the amp on and off, or buy some kind of power management system.

Sounds like a little thing but getting up and down (pure laziness on my part) has really limited the amount of time I spend listening to my main system.

I don't believe there is a sub out which may be a deal breaker as I have a pair of speakers that begs for a sub and I swore my next system would have one.

Somebody correct me if I'm wrong on these.

 

[DanielT]

If we ignore factors like THD + N, daming factor and linearity what exactly is, on paper stated 40 W? Is it enough for good sound? Just to make it difficult. What type of measured effect is of interest?
Take this little vintage from NAD. Designed with high dynamic power.

The question is what matters when you play music . Picture note that it was in 8 Ohm. Check out the video and see what the little bastard can do with 2 Ohm. Incredible.

NAD 7240PE Stereo Receiver (1988)
NAD 7240PE
Specifications
Tuning range: FM, MW
Power output: 40 watts per channel into 8Ω (stereo)

https://www.hifiengine.com/manual_library/nad/7240pe.shtml

 

[DanielT]

With a sensitivity of 90 dB (2.83 V, 1 m) around 2x150-175 W in 8 ohms, if you want voltage / power over for dynamically uncut recordings

If you mainly listen to today's normal overcompressed products, however, would believe 2x20 W. 8O is enough.

Edit:

I created a new thread that addresses your question from a more general perspective:

https://audiosciencereview.com/foru...he-buck-combination-amplifier-speakers.26465/

 

[AnalogSteph]

With a sensitivity of 90 dB (2.83 V, 1 m) around 2x150-175 W in 8 ohms, if you want voltage / power over for dynamically uncut recordings

If you mainly listen to today's normal overcompressed products, however, would believe 2x20 W. 8O is enough.

Recommended amplifier wattage from speaker manufacturers is often given for about 103 dB SPL @ 1 m anechoic (i.e. 20 W in this case), which is a rule of thumb for a pair of speakers at typical hi-fi listening distances in a typical room as well.

It is very hard to do this with any sort of precision, as a lot will depend on actual listening distance and how well the room is damped, not to mention that preferred listening levels will vary quite a bit between people as well (I tend to come in about 10 dB less than average myself, so I'll never need the most powerful amps but what's happening at the bottom end of dynamic range is of correspondingly greater concern to me).

It is also possible to be limited not by amplifier power but merely overall gain. If you have your playback chain set up to handle even the most dynamic material while keeping levels roughly constant across the board, average output levels will obviously be lower than e.g. when playing typical modern(ish) nonclassical material straight from CD.

 

[DanielT]

Well, modern music. Two pictures, same song. Picture no. 1 from 1989. Picture 2 newer same song compressed. An evenly thick batter. It does not seem to place any major demands on the amplifier. That's good.

Then there is another thing that the sound, picture 2, sounds rubbish. Good for the amplifier, sad for our ears.