Benchmark AHB2 and Perlisten R7T impedance question

[4D_Coaxial_Cube]

The specs for the Benchmark AHB2 are as follows for power outputting from it.

Continuous Average Output Power​

< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz

• 100 Watts per channel into 8 Ohms, both channels driven
• 130 Watts per channel into 6 Ohms, both channels driven
• 190 Watts per channel into 4 Ohms, both channels driven
• 240 Watts per channel into 3 Ohms, both channels driven
• 200 Watts into 16 Ohms, bridged mono
• 380 Watts into 8 Ohms, bridged mono
• 480 Watts into 6 Ohms, bridged mono

All speakers have variations in input impedance. Select loads based on nominal impedances not minimum impedances. The AHB2 is stable into all loads. The AHB2 is conservatively rated at an output level where THD+N is < 0.0003 % instead of the more typical 1% THD+N. Power at 1% THD will be higher.

The Perlisten R7T speakers are Rated as a 4ohm Nominal. I realize that if one were to buy 2 of them they could be used to bi amp the speakers with each delivering power to the left and right at 190 watts per channel, but thats a loss of 120watts per amp when compared to the 480 watts in the bridged mono configuration into 6 ohms. Would driving the Perlisten R7T 4 ohm speakers with a 6 ohm nominal load from the amp in bridged mode be possible or would this damage the amps? I seem to remember reading once it is better for an amp to have a lower impedance than for the speaker to as the current draw at a lower ohm can be more destructive but I dont know if I am remembering this right. Thanks.

 

[RayDunzl]

The AHB2 will likely protect itself from problems you present to it.

Since you are unlikely to use "full power" often (if you do you need a bigger amp), I'd rate it unlikely to damage the thing.

https://cdn.shopify.com/s/files/1/0321/7609/files/AHB2_Manual_-_Rev_H.pdf?v=1602610101

If you can blow it up, @John_Siau would probably like to hear about it.

 

[DVDdoug]

Would driving the Perlisten R7T 4 ohm speakers with a 6 ohm nominal load from the amp in bridged mode be possible or would this damage the amps?

Your speakers are 4-Ohms so that's "not allowed". (You can't get a 6-Ohm load with those speakers.)

I seem to remember reading once it is better for an amp to have a lower impedance than for the speaker to as the current draw at a lower ohm can be more destructive but I dont know if I am remembering this right.

Resistance (or impedance) is "the resistance to current flow". If you cut the resistance/impedance in half you get twice the current and twice the wattage (if the voltage remains the same).

The amplifier's impedance rating is for the minimum load impedance. The actual output impedance of the amplifier is usually less than 1-Ohm (sometimes published as the "damping factor"). We don't want "impedance matching".

 

[fpitas]

I seem to remember reading once it is better for an amp to have a lower impedance than for the speaker to as the current draw at a lower ohm can be more destructive but I dont know if I am remembering this right. Thanks.

Typically the amp is well under 0.1 ohm. That has nothing to do with its minimum rated load impedance, nor its maximum allowable current.

This might help explain:

Audio Myth - "Damping Factor Isn't Much of a Factor"

Myth - "Damping Factor Isn't Much of a Factor" Myth - "A Damping Factor of 10 is High Enough" Myth - "All Amplifiers Have a High-Enough Damping Factor" Where did these Myths Originate? These myths seem to trace back to a well-known paper (PDF) written by Dick Pierce. His analysis shows that a...

benchmarkmedia.com

 

[4D_Coaxial_Cube]

The AHB2 will likely protect itself from problems you present to it.

Since you are unlikely to use "full power" often (if you do you need a bigger amp), I'd rate it unlikely to damage the thing.

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https://cdn.shopify.com/s/files/1/0321/7609/files/AHB2_Manual_-_Rev_H.pdf?v=1602610101

If you can blow it up, @John_Siau would probably like to hear about it.

Thanks for the reply. I just reached out to Benchmark via phone and talked to a nice gentleman with professionalisms and information about the ohm ratings discussed above, and this rep explained that these stated numbers are not about matching with speakers. They have these amplifiers stress tested with a 1khz signal ran at maximum output to get the numbers we see on their site/manuals. He explained that they frequently pair their amps with 1 and 2 ohm speakers no problem at their facility, and they also have partnered with Martin Logan and other speaker makers for shows to great success with the amps and speakers both having no problems.

 

[fpitas]

You really can't go wrong with Benchmark.

 

[Kal Rubinson]

Thanks for the reply. I just reached out to Benchmark via phone and talked to a nice gentleman with professionalisms and information about the ohm ratings discussed above, and this rep explained that these stated numbers are not about matching with speakers. They have these amplifiers stress tested with a 1khz signal ran at maximum output to get the numbers we see on their site/manuals. He explained that they frequently pair their amps with 1 and 2 ohm speakers no problem at their facility, and they also have partnered with Martin Logan and other speaker makers for shows to great success with the amps and speakers both having no problems.

I have used bridged AHB2s with many speakers, including the Perlisten S7t (also rated at 4ohms), without any problems.

 

[CleanSound]

I would buy th S7t instead, if you plan to drop this kind of money.

 

[4D_Coaxial_Cube]

Typically the amp is well under 0.1 ohm. That has nothing to do with its minimum rated load impedance, nor its maximum allowable current.

This might help explain:

Audio Myth - "Damping Factor Isn't Much of a Factor"

Myth - "Damping Factor Isn't Much of a Factor" Myth - "A Damping Factor of 10 is High Enough" Myth - "All Amplifiers Have a High-Enough Damping Factor" Where did these Myths Originate? These myths seem to trace back to a well-known paper (PDF) written by Dick Pierce. His analysis shows that a...

benchmarkmedia.com

I would buy th S7t instead, if you plan to drop this kind of money.

Perhaps you would. I got the R7T pair yesterday after driving 8 hours for them and 8 hours back. The price was 6500 usd and the seller only had them a few months before moving on. I saw the S7T's used for 11700, but I realized I would like to live...and having a wife in my old age might come in handy. Aside from that I also suffer from extreme sensitivity to fatigue and highs can drive me crazy after just a short bit. Of course I love the wow factor of extremely detailed and sparkly profiles, but it goes from wow factor to ow factor fast with my ears/brain. I havent heard the S7T's personally and I suppose that is a good thing for my marriage and ears.

 

[CleanSound]

Aside from that I also suffer from extreme sensitivity to fatigue and highs can drive me crazy after just a short bit. Of course I love the wow factor of extremely detailed and sparkly profiles, but it goes from wow factor to ow factor fast with my ears/brain.

I own the S7t. There is no listening fatigue and it's not sparkly neither. The frequency response is as flat as you can get without DSP.

I think there is misconception amongst people who thinks metal tweeters somehow are "bright," maybe because the reflective color of the metal? And somehow soft dome tweeters are "smooth," maybe because some soft dome uses silk, so they associate it with "smooth?"

All the Perlisten speakers are as neutral as you can get without DSP. The difference is performance in everything else, such as distortion, directivity, bass extension, resonance, deffractions, etc. etc.

The R7t are great speakers, in fact, any Perlisten speakers are great. My philosophy after going through 7 pairs of speakers, that if I am looking for end game, well. . .I better not have any desire for upgrades.

Enjoy the R7t, they are great speakers.

 

[raz1969]

i also have perlistens but the s5t. i dont think the highs are bright at all. i was worried about Be tweets and them being strident but that isnt the case at all.

 

[4D_Coaxial_Cube]

I own the S7t. There is no listening fatigue and it's not sparkly neither. The frequency response is as flat as you can get without DSP.

I think there is misconception amongst people who thinks metal tweeters somehow are "bright," maybe because the reflective color of the metal? And somehow soft dome tweeters are "smooth," maybe because some soft dome uses silk, so they associate it with "smooth?"

All the Perlisten speakers are as neutral as you can get without DSP. The difference is performance in everything else, such as distortion, directivity, bass extension, resonance, deffractions, etc. etc.

The R7t are great speakers, in fact, any Perlisten speakers are great. My philosophy after going through 7 pairs of speakers, that if I am looking for end game, well. . .I better not have any desire for upgrades.

Enjoy the R7t, they are great speakers.

Have you seen the measurements Ron from New Record Day took of both pairs and compared them? When he measured them the R7T were flatter.

 

[CleanSound]

Have you seen the measurements Ron from New Record Day took of both pairs and compared them? When he measured them the R7T were flatter.

According to Perlisten's public spec sheet, it's pretty much the same.

I have not seen Ron's measurements.

 

[4D_Coaxial_Cube]

According to Perlisten's public spec sheet, it's pretty much the same.

I have not seen Ron's measurements.

I encourage you to check his measurements out in his video. His measurements do in fact show a strikingly similar response, but the high end had a rise that caused concern for me. It would have taken me half the travel time for me to get to the closest dealer to hear them side by side, but I did not really want to do that because it wouldnt have simply been twice as much for me to go from 10k to 20k, it would have been more than three times as much for me to move up to the S7T. I am curious though, why did you settle for the S7T as your endgame speakers while knowing there are more expensive speakers with fewer compromises? Its easy to say the things that you said but its hard to find the logic when Germany, South Korea, Japan, have audio fairs that surely have better speakers than the S7T. You definitely seem to have a desire to really have the best of the best, and why wouldnt you? Perhaps its time for you to go to some fests around the world and figure it out!

 

[CleanSound]

I encourage you to check his measurements out in his video. His measurements do in fact show a strikingly similar response, but the high end had a rise that caused concern for me. It would have taken me half the travel time for me to get to the closest dealer to hear them side by side, but I did not really want to do that because it wouldnt have simply been twice as much for me to go from 10k to 20k, it would have been more than three times as much for me to move up to the S7T. I am curious though, why did you settle for the S7T as your endgame speakers while knowing there are more expensive speakers with fewer compromises? Its easy to say the things that you said but its hard to find the logic when Germany, South Korea, Japan, have audio fairs that surely have better speakers than the S7T. You definitely seem to have a desire to really have the best of the best, and why wouldnt you? Perhaps its time for you to go to some fests around the world and figure it out!

Speaker measurements are hard to do, especially when you don't have a Klippel NFS or an anechoic chamber. I know Ron doesn't have neither. (And not to mention, I believe Ron is good friends with Danny Ritchie, which makes me suspicious of his credibility).

There are only few reviewers, who I trust with speaker measurements. Amir, Erin, James Larson and anyone else with a Klippel NFS and competent understanding of loudspeakers.

I 100% trust Perlisten's measurements, (a) they have been verified by James Larson. (b) James Larson measured both the S7t and R7t, which corroborated with Perlisten's published specs.

I have auditioned both S7t and R7t, enough difference for me to spend that kind of money.

And as far as I know, there aren't many speakers out there that are in the same playing field as the Perlisten and Revel at this price range.

 

[CleanSound]

i was worried about Be tweets and them being strident but that isnt the case at all.

Why would you associate Be with strident? Be is probably one of the most ideal cone material, the break up frequency is extremely high. It's extremely stiff, it's extremely light. There are very few materials better than Be for cone.

I keep hearing people making these statements about metal tweeters that they are "harsh" and "bright." Where did this myth come from? Is it because the shiny and reflective nature of metal?

 

[4D_Coaxial_Cube]

Speaker measurements are hard to do, especially when you don't have a Klippel NFS or an anechoic chamber. I know Ron doesn't have neither. (And not to mention, I believe Ron is good friends with Danny Ritchie, which makes me suspicious of his credibility).

There are only few reviewers, who I trust with speaker measurements. Amir, Erin, James Larson and anyone else with a Klippel NFS and competent understanding of loudspeakers.

I 100% trust Perlisten's measurements, (a) they have been verified by James Larson. (b) James Larson measured both the S7t and R7t, which corroborated with Perlisten's published specs.

I have auditioned both S7t and R7t, enough difference for me to spend that kind of money.

And as far as I know, there aren't many speakers out there that are in the same playing field as the Perlisten and Revel at this price range.

By your logic you should have been considering speakers at least twice as much if you were going to spend that kind of money.

 

[CleanSound]

By your logic you should have been considering speakers at least twice as much if you were going to spend that kind of money.

I don't get your conclusion based on my logic. Please elaborate.

 

[Mnyb]

Why would you associate Be with strident? Be is probably one of the most ideal cone material, the break up frequency is extremely high. It's extremely stiff, it's extremely light. There are very few materials better than Be for cone.

I keep hearing people making these statements about metal tweeters that they are "harsh" and "bright." Where did this myth come from? Is it because the shiny and reflective nature of metal?

I think when they where new on the market, the speaker manufacturers wanted you to hear they new shiny tweeters and lifted the response a bit , and they did not understand directivity either so the increased off axis treble energy just went into the room combined with a jarring directivity discontinuity in the low treble and midrange .

Old dome tweeters in other materials migth have been the opposite and did not project much treble energy of axis .
And speaker designers of the time had yet not learned to balance such factors ?

And as mentioned a tendency to over cook the treble response due to “details” the sound now have more “micro details” ( aka more treble ).

I think it coincided with the rise of small two way speakers as the norm ?

I think you can blame B&W too all thier speakers sounds like kazoos in the upper range ( a slight exaggeration)

And audiophiles did not have room treatment or eq or even simple tone controls ( because that was somehow bad )

And of two bad’s many picks slightly dull over bright

 

[4D_Coaxial_Cube]

I would buy th S7t instead, if you plan to drop this kind of money.

My philosophy after going through 7 pairs of speakers, that if I am looking for end game, well. . .I better not have any desire for upgrades.

And as far as I know, there aren't many speakers out there that are in the same playing field as the Perlisten and Revel at this price range.

You reasoned that if one were willing to spend 10k then why not go ahead and spend 20k, and I tell you that you should have continued that line of thinking and doubled it again. You heard the 2 Perlisten models mentioned, and my advice is for you to listen to 40k dollar speakers and see if there is a reason to upgrade.. I am sure there are.