MartinLogan Renaissance 15A vs. Revel PerformaBe F328Be

[Sonnie Parker]

With the AHB2 switch set to 4v, the SHD reached -20 for 2.83v with a 1kHz tone...and the F328 measured 93.2dB at 1 meter. With the AHB2 switch at 2v the SHD is at -26, which is what it should be, and the F328 measured 93.5dB at 1 meter. For the 15A a 500Hz tone was used and with 4v the SHD reached -24 for 2.83v and measured 90.1dB at 1 meter, and at 2v the SHD is at -30 and measured the same 90.1dB.


F328 4v

F328 2v

15A 4v

15A 2v

 

[RichB]

That looks good.
So 2.0 to 2.5 dB can be attributed to room gain.

Here are the computed results from this online calculator:
Peak SPL Calculator (homestead.com)

Revel 328Bes:

And less for the 15As:

The 15As may be less due to current limiting, but if the Clip are lighting before the temp (or the same time) the amp should be supplying enough current to achieve the maximum voltage.

Going from the Benchmarks voltage specification into 4 Ohms:, the voltage gain is 45.52 Vrms into 4 Ohms, bridged mono.

• 29.03 dBV, 31.25 dBu, 28.28 Vrms into 8 Ohms, both channels driven
• 28.92 dBV, 31.14 dBu, 27.93 Vrms into 6 Ohms, both channels driven
• 28.81 dBV, 31.03 dBu, 27.57 Vrms into 4 Ohms, both channels driven
• 28.57 dBV, 30.79 dBu, 26.83 Vrms into 3 Ohms, both channels driven
• 27.14 dBV, 29.36 dBu, 22.76 Vrms into 2 Ohms, both channels driven
• 35.05 dBV, 37.27 dBu, 56.57 Vrms into 16 Ohms, bridged mono
• 34.83 dBV, 37.05 dBu, 55.14 Vrms into 8 Ohms, bridged mono
• 34.59 dBV, 36.81 dBu, 53.67 Vrms into 6 Ohms, bridged mono
• 33.16 dBV, 35.38 dBu, 45.52 Vrms into 4 Ohms, bridged mono

Use dBV to calculate the peak SPL from your speaker/amplifier combination. Use the following formula: Amplifier output voltage in dBV + speaker sensitivity at 2.83V - 9 dB. Example: (29.03 dBV at 8 Ohms) + (90 dB SPL @ 2.83V 1m) - 9 dB = 110 dB SPL at 1 meter

Just for fun, I will treat the 328Be are 4 Ohm (there are actually >5 Ohm in the mid and upper frequencies) and the 15As as 2 Ohms discounting it a bit 20 volts gain.

AHB2 bridged mode
The 328Bes calculation is 45.5 + 93.5 - 9 = 129.7 dBV.
The 15As calculation is 22 + 90 - 9 = 101 dBV.

I doubt the 328Bes are going to linear out the 129 dB and don't know if they can handle it.
But they are going to get a lot louder than the 15As with the AHB2s.

So the voltage calculation shows a big hit to output for the 15As but two speakers should be capable of 103 dB.
You already knew you needed more power, but the analysis is interesting.

- Rich

 

[Sonnie Parker]

The first thing I noticed about the F328's is that they were NOT any louder than the 15A's... same volume level and almost the same sound level to my ears. Proof of that is If I use the same setting on the SHD for both, they are very very similar in loudness. The F328 reaches 93.5dB at 2v when the SHD is set to -26. The 15A reaches 93.2dB at 2v when the SHD is set to -26. Very difficult for me to hear .3dB when it takes 10-15 minutes to swap out the speakers. There's more power going to the 15A's, so it will compensate. Anyway... the SPL level for the 15A at the same -26 setting on the SHD is as follows.

 

[Sonnie Parker]

I think the difference is with the 15A's you are getting more than the 380 watts because the impedance is lower than the 328's. That compensates for the dB level. Something definitely doesn't add up in the calculations vs real world numbers.

 

[RichB]

The first thing I noticed about the F328's is that they were NOT any louder than the 15A's... same volume level and almost the same sound level to my ears. Proof of that is If I use the same setting on the SHD for both, they are very very similar in loudness. The F328 reaches 93.5dB at 2v when the SHD is set to -26. The 15A reaches 93.2dB at 2v when the SHD is set to -26. Very difficult for me to hear .3dB when it takes 10-15 minutes to swap out the speakers. There's more power going to the 15A's, so it will compensate. Anyway... the SPL level for the 15A at the same -26 setting on the SHD is as follows.

View attachment 41739

If you are evaluating loudness then it is better to measure 1 kHz, better yet 2 kHz where our hearing is more sensitive. I have seen different charts but this could be 10 dB maybe more at 2 kHz. The 15As at 2.5 kHz are 2 Ohms and the 328s are 6 Ohms.
That is huge and the AHB2s are going to be able to deliver maximum power into the 328Bes and will voltage drops drastically, It is possible that there is very little gain to bridging this amp for the 15As.

The voltage measurements between similar efficiency should be similar volume but the AHB2s simply run out of gas much earlier with the 15As. The watts will be delivered but at lower maximum voltage, so there should be much less output into the 15As.

Are the 328Bes able to reach your loudness goals with the AHB2s?

- Rich

 

[Sonnie Parker]

I evaluate loudness with music... the same songs over and over and over... countless times. That will cover all the frequencies above 80Hz (crossover)... not just one or two. I did the SPL meter in REW for show and tell only.

No... neither speaker can reach the loudness I need for a few songs when the AHB2 is set to 4v. Both can reach that loudness at 2v, BUT temp and clip lights all start flashing at the same level on the SHD for both speakers, and they are at the same max dB level on the SPL meter in REW... (about 107dB within .5dB of each other).

107dB is pretty loud today for me... and it is hard to imagine we use to sit in our vehicles and didn't think twice about 140dB pounding our ears to the tinnitus state which mine suffer from today.

 

[ddude003]

@RichB Your above Peak SPL Calculation stating that the 15A speaker sensitivity is 90 when the Martin Logan Spec states it is 92 dB/2.83 volts/meter... This gives us 111.1 dB SPL at listening position vs 112.2 db...

I think this is an issue with using an amplifier that maps to a box speaker via the impedance expecting a box speaker... Is the Amp broken? No... Is the Speaker broken? No... Just architecturally a mismatch with the 15a... I wonder what a set of Zeros would do to the equation...

 

[Sonnie Parker]

@RichB Your above Peak SPL Calculation stating that the 15A speaker sensitivity is 90 when the Martin Logan Spec states it is 92 dB/2.83 volts/meter... This gives us 111.1 dB SPL at listening position vs 112.2 db...

He is going off what I measured, however the power will probably be higher for the 15A since it has a lower impedance, and he's using the same power for both speakers. That may be why there is a difference in level with the calculations but not in my room here.

 

[RichB]

I think we have firmly established that @Sonnie likes it loud.

- Rich

 

[Sonnie Parker]

I think we have firmly established that @Sonnie likes it loud.

- Rich

HUH? WHAT DID YOU SAY?

 

[Sonnie Parker]

I think this is an issue with using an amplifier that maps to a box speaker via the impedance expecting a box speaker... Is the Amp broken? No... Is the Speaker broken? No... Just architecturally a mismatch with the 15a... I wonder what a set of Zeros would do to the equation...

The amp works if you don't mind some flashing lights all along... if you can live comfortably on the edge. I personally prefer a bit more headroom, even if I don't need it.

The Magtechs did not show up today, but should be here tomorrow. I'll check the SHD level on it compared to the AHB2... should be interesting... at least for me.

FWIW... I purchased a pair of Stereo amps to have the two extra channels for just in case one day I might want to bi-amp or add wides again, or just be stupid. I thought about the mono Magtechs... but certainly overkill on a grandish level. The nice thing about the Stereo version is Roger wrapped the rail fuse on one channel of each amp, so that massive power supply is only feeding one module/channel of each amp... thus a little more efficiency... not that I need it with those amps, BUT... we like it like that.

 

[RichB]

The amp works if you don't mind some flashing lights all along... if you can live comfortably on the edge. I personally prefer a bit more headroom, even if I don't need it.

The Magtechs did not show up today, but should be here tomorrow. I'll check the SHD level on it compared to the AHB2... should be interesting... at least for me.

FWIW... I purchased a pair of Stereo amps to have the two extra channels for just in case one day I might want to bi-amp or add wides again, or just be stupid. I thought about the mono Magtechs... but certainly overkill on a grandish level. The nice thing about the Stereo version is Roger wrapped the rail fuse on one channel of each amp, so that massive power supply is only feeding one module/channel of each amp... thus a little more efficiency... not that I need it with those amps, BUT... we like it like that.

Are these these your new Magtechs?
Sanders Sound Systems - Magtech Amp

Regulated amplifiers have advantages, especially where the wall power can vary, say on cloudy, calm days
But they can have less headroom for instantaneous peaks. Also amps, with less distortion or compression may not be perceived as loud. I cooked a Salon1 midrange with a Sunfire Cinema Grand Signature amps (400 WPC) it was loud, possibly Sonnie loud (a new term of art). Looking back at it, I suspect that the amps must have been clipping providing a lot of energy to the upper range.

I don't understand, based on the voltage math and load, how the 328Bes are not quite loud enough.
The math for 15As on the other hand shows that the AHB2 is not going to be able to provide the current to maintain the voltage into load that is at 2 Ohms and lower.

On paper, the stereo Magtech may be able to provide the current to achieve a higher level but the volume produced may not be greater than the 328Be/AHB2.

The 1kHz sensitivity was measured for both speakers so I am not sure we have an apples to apples comparison, but, one set showed the 328Bes 3 dB more efficient, so they need half the power. They are 4 Ohm so 500 WPC should produce the same volume as an amp that with 1000 WPC driving a speaker 3 dB less efficient.
The 15As current, requirement cause the AHB2s to limit voltage/volume.

Is it possible to accurately measure volume produced playing your demanding tracks with the Mic?

- Rich

 

[RichB]

The amp works if you don't mind some flashing lights all along... if you can live comfortably on the edge. I personally prefer a bit more headroom, even if I don't need it.

The Magtechs did not show up today, but should be here tomorrow. I'll check the SHD level on it compared to the AHB2... should be interesting... at least for me.

FWIW... I purchased a pair of Stereo amps to have the two extra channels for just in case one day I might want to bi-amp or add wides again, or just be stupid. I thought about the mono Magtechs... but certainly overkill on a grandish level. The nice thing about the Stereo version is Roger wrapped the rail fuse on one channel of each amp, so that massive power supply is only feeding one module/channel of each amp... thus a little more efficiency... not that I need it with those amps, BUT... we like it like that.

Bi-amping can slightly increase output, using the AHB2 clip indicators, about 1 dB gained by bi-amping the Salon2s. FWIW, I did do a 2 person SBT bi-amp verses stereo with the AHB2s and my friend and I passed. You would think the 15As would be less likely to benefit because they bass section is powered, although it could provide a clean signal when the upper amp is bringing down the house.

- Rich

 

[Sonnie Parker]

Are these these your new Magtechs?
Sanders Sound Systems - Magtech Amp

Regulated amplifiers have advantages, especially where the wall power can vary, say on cloudy, calm days
But they can have less headroom for instantaneous peaks.

Per Roger and his math, the Magtechs will produce as much as 2400 watts peak... no issue at all with headroom.

Is it possible to accurately measure volume produced playing your demanding tracks with the Mic?

That's exactly what I did... I reached 107dB with both amps... see previous post (you didn't read it uh-huh)...

No... neither speaker can reach the loudness I need for a few songs when the AHB2 is set to 4v. Both can reach that loudness at 2v, BUT temp and clip lights all start flashing at the same level on the SHD for both speakers, and they are at the same max dB level on the SPL meter in REW... (about 107dB within .5dB of each other).

107dB is pretty loud today for me... and it is hard to imagine we use to sit in our vehicles and didn't think twice about 140dB pounding our ears to the tinnitus state.

Can't bi-amp the 15A's... only one set of speaker posts. Bridged will provide the most power either way though.

 

[AJ Soundfield]

Per Roger and his math, the Magtechs will produce as much as 2400 watts peak... no issue at all with headroom.

Nice to know, but unfortunately, the most relevant number is measured power into 2 ohms, since you're below 3 above 4k ish on the MLs

 

[Sonnie Parker]

He states his stereo amps cap out at 900 watts continuous power... per logic for AB amps and the 120 volts from wall plug, and based on the efficiency of his amps, which is better than most with his regulated power supply.

We'll hopefully see what sort of levels they can bring tonight, Lord willing!

 

[AJ Soundfield]

Yep, we will. Hopefully some day you can measure the 2 ohm output, as it remains unicornish.
Suspect you'll be just fine regardless.

cheers

 

[RichB]

Per Roger and his math, the Magtechs will produce as much as 2400 watts peak... no issue at all with headroom.



That's exactly what I did... I reached 107dB with both amps... see previous post (you didn't read it uh-huh)...


Can't bi-amp the 15A's... only one set of speaker posts. Bridged will provide the most power either way though.

Sorry, I missed that post. Still, I am surprised that you cannot get over 110 dB with the 328Bes and AHB2 bridged.
It is what it is.

Your new Magtechs won't be flashing and seriously disturbing your cool

- Rich

 

[Sonnie Parker]

I think I can agree with both of you on your posts... lol... imagine that.

I have an appointment on Thursday or Friday to discuss the M1 Audio Analyzer with Spectral.

 

[ddude003]

I have an appointment on Thursday or Friday to discuss the M1 Audio Analyzer with Spectral.

Interesting little toy... Next thing you know you will have one of those Spinorama whirly gigs...

 

[Sonnie Parker]

Interesting little toy... Next thing you know you will have one of those Spinorama whirly gigs...

That would be CONSIDERABLY out of my price range... and I'm not even sure I want to devote part of my time doing audio analysis anyway, so this is far from a done deal. I'd almost rather buy the equipment and let someone else do the testing.

 

[RichB]

He states his stereo amps cap out at 900 watts continuous power... per logic for AB amps and the 120 volts from wall plug, and based on the efficiency of his amps, which is better than most with his regulated power supply.

We'll hopefully see what sort of levels they can bring tonight, Lord willing!

The trouble is power does not go far into 2 ohms and lower.
I plugged in the Magtechs 900 Watts into this Ohms law calculator:
Ohms Law Calculator

Using my spreadsheet for the 15As (at 90 dB) I get 113 dB single speaker.

Magtech

42​

45​

23.42926​

113.4293​

The AHB2 is values:

The same calculation for the AHB2 yields 110 dB

AHB2 Bridged 2 Ohms

31​

45​

20.79151​

110.7915​

It may be that the AHB2 really cannot provide 31 Volts into 2 Ohms or the 15As dropped further.

It will be interesting to see how the Magtechs perform.
When you get to these power levels, 3 dB costs a lot.

- Rich

 

[Sonnie Parker]

I posted an impedance overlay back at post #2 ... https://www.avnirvana.com/threads/m...5a-vs-revel-performabe-f328be.8654/post-65976

They cross paths at 1.76kHz... might be interesting to see what each does SPL wise at that impedance.

I did go back and measure the 15A at 1kHz to have that apples to apples comparison... it makes it to 91.2dB.

Here is 500Hz again...

And 1000Hz...

 

[RichB]

I posted an impedance overlay back at post #2 ... https://www.avnirvana.com/threads/m...5a-vs-revel-performabe-f328be.8654/post-65976

They cross paths at 1.76kHz... might be interesting to see what each does SPL wise at that impedance.

I did go back and measure the 15A at 1kHz to have that apples to apples comparison... it makes it to 91.2dB.

Here is 500Hz again...

View attachment 41772


And 1000Hz...

View attachment 41773

I used 90 dB and 2 Ohms in the spreadsheet but add 3 dB since it is likely that the energy is in the 2K range.
I read somewhere that the AHB2 might deliver more power in stereo mode into 2 Ohms.

- Rich

 

[Sonnie Parker]

With the Magtech, the SHD sits on -30dB at 2.83v with a 1kHz tone. However, the Magtech is a 2.2v amp, so we would have to add a little bit (,5dB) to the -30dB to make it match the 2v of the AHB2. Not enough to matter really, but that is a minimum of 4dB more headroom.

At the same volume level of the AHB2 (-26dB)... we can see that it is indeed about 4.5dB... 4.6dB to be exact. 95.8dB vs 91.2dB (from my last post).

AND NO FLASHING LIGHTS ON THE MAGTECH!!!