AHB2 real world power output - enough?

[ex audiophile]

I have a number of these little devils and love them. Even if they weren't so well engineered I appreciate them for the size/weight factor. Like many of us I've wondered if 100 watts/channel is sufficient for my particular applications. Rory Rall at Benchmark told me i'd get about 20 db above the speaker sensitivity rating so for an 88 speaker the amp could produce roughly 108 db without clipping. For my particular setup I felt this would be "more than enough". The setup is a Node2i digital out/STR preamp/AHB2 in stereo(hi gain)/Revel 106be speakers supported by a pair of JLA f112v2 subs. Because of the subs I never thought the amp would run out of steam, my room is 16 x 20 x 9 foot ceilings and the LP is 14 feet from the speakers. Sometimes I listen loud but again, I was convinced the amp had plenty of headroom.

Today, while on the exercise bike i selected AC/DC's Hells Bells. I don't listen to the track often but as you know the beginning is killer, and at higher volumes still gives me goosebumps. I feel like I'm at an AudioholicsAnonymous meeting when I say this, but I had the volume at about -15 (or so) . I know, don't start, it was ear damaging but the older you get the lesser the consequences seem. I didn't measure the SPL but I know it was way up there. Anyway, while getting my goosebumps I noticed some flickering lights from the AHB2, and of course they were the right/left clipping warning lights. I also heard the speakers seeming to be a bit distressed. I immediately lowered the volume of course but I did repeat the episode and clearly at -10 to -15 the amp was clipping.

The Revel's are fairly efficient (high 80s i believe) and in the Audioholics review Larson characterized them as "easy to drive". Especially given the support from the subs I really thought I would never see the amp clip. Based on this experience I clearly need to keep the volume reasonable and preserve my hearing but now I realize I'm closer to the max ouput of the amp than I thought.

This is of course purely anecdotal but I thought it worthwhile to share. Now instead of considering the AHB2 to be "more than enough" for my setup I consider it just "sufficient". Your situation is of course different than mine, but my takeaway is always err towards more power. I think it was @restorer-john who recommended a minimum of 200/channel. I second that motion.

 

[DonH56]

So when are you buying another set so you can bridge them all?

 

[dougi]

Yes if you want to support 105dBA peaks per speaker in your room then 100W/ch is not enough. You would need maybe 500W RMS for a single channel. (assuming efficiency 86dBA/1m/1W) That is very loud though, even if it is considered "reference level" in home theatre terms. 10dB below that is still way loud for most people and that only requires less than 100W.

Yeah, you said (a number of them). How many indeed do you have!

PS in music, my preference is the "Helles Belles" soundtrack, a 60s biker chick b grade movie. Great songs though in the 60s swing vein.

 

[ex audiophile]

So when are you buying another set so you can bridge them all?

Lol, I tend to go over the top a bit, and have an AHB devoted to my new center channel (426be) in a surround system. I will likely pull that one out to join its mate in the 2 channel setup. I have a 5 channel amp (MCA 525) in the surround setup that can handle the center. It's pretty much all for fun at this point

 

[ex audiophile]

Yes if you want to support 105dBA peaks per speaker in your room then 100W/ch is not enough. You would need maybe 500W RMS for a single channel. (assuming efficiency 86dBA/1m/1W) That is very loud though, even if it is considered "reference level" in home theatre terms. 10dB below that is still way loud for most people and that only requires less than 100W.

Yeah, you said (a number of them). How many indeed do you have!

PS in music, my preference is the "Helles Belles" soundtrack, a 60s biker chick b grade movie. Great songs though in the 60s swing vein.

I'll have to check that out. Since we're still in the AA meeting, i'll admit to 3 AHBs with one more on the way (they've been back ordered again).

 

[Panelhead]

The culprit might be the track also. I have a CD that was mastered too hot. Digital clipping is hard on amplifiers and speakers.

 

[ex audiophile]

The culprit might be the track also. I have a CD that was mastered too hot. Digital clipping is hard on amplifiers and speakers.

If any group is guilty of overdriving amps it would be AC/DC !

 

[ebslo]

Yes if you want to support 105dBA peaks per speaker in your room then 100W/ch is not enough. You would need maybe 500W RMS for a single channel. (assuming efficiency 86dBA/1m/1W)

Looks about right, but the A-weight curve makes a definitive answer for dbA difficult as it depends a lot on source frequency content. Bombadil's math is correct for unweighted intensity.

 

[Beershaun]

You should sell them and get something more powerful. PM me and I will take them off your hands so you no longer have to worry about them. Say...$250 to make your problem go away.

 

[ex audiophile]

You should sell them and get something more powerful. PM me and I will take them off your hands so you no longer have to worry about them. Say...$250 to make your problem go away.

Perfect, you buy my wimpy little AHB2s and I'll use the money to buy Amir's gigawatt monoblocks

 

[Beershaun]

Perfect, you buy my wimpy little AHB2s and I'll use the money to buy Amir's gigawatt monoblocks

Deal!

To actually answer the question, I agree with the above folks to try bridging your amps (since you have 3) to do an a/b test and see what the difference is. You could set one up to one channel in bridged configuration and set a second one up for the other channel in regular configuration and compare them side by side.

 

[ex audiophile]

So when are you buying another set so you can bridge them all?

Forget bridging them all, with a couple Boulder 3050s I could Rule Them All

ps; The shipping weight of the Boulder is 563 lbs. For April Fool's day we should tell Amir that we're having one drop shipped to him for testing

 

[Selah Audio]

I have used the AHB2 at a couple of audio shows. Plenty of output to drive my designs.

 

[ex audiophile]

I have used the AHB2 at a couple of audio shows. Plenty of output to drive my designs.

But have you played AC/DC at -10 . Jeez, the name of the band should give us pause...

 

[ebslo]

The review of the F226Be at Erin's Audio Corner found it crossed the -3dB compression limit at 106dB. I would expect the 106be (M106? M126be?) to compress more/lower so expect very diminishing returns from higher amp power into this speaker.

 

[ex audiophile]

The review of the F226Be at Erin's Audio Corner found it crossed the -3dB compression limit at 106dB. I would expect the 106be (M106? M126be?) to compress more/lower so expect very diminishing returns from higher amp power into this speaker.

my bad, they are 126bes.

 

[Selah Audio]

But have you played AC/DC at -10 . Jeez, the name of the band should give us pause...

Oh but you haven't heard "She's Got The Jack" on a small old-school portable cassette player.

 

[watchnerd]

I don't understand this thread.

Any amp can be driven to clipping / auto-protect mode if you run it hard enough, long enough.

This isn't a Benchmark or AHB2-specific issue.

And 200 watts is only 3 dB more gain than 100 watts...

 

[watchnerd]

Yes if you want to support 105dBA peaks per speaker in your room then 100W/ch is not enough. You would need maybe 500W RMS for a single channel. (assuming efficiency 86dBA/1m/1W) .

IMHO, people who want to play that loud on a regular basis should be buying different speakers with higher sensitivities in the first place.

 

[ebslo]

This isn't a Benchmark or AHB2-specific issue.

And 200 watts is only 3 dB more gain than 100 watts...

IMO, you understand this thread perfectly.