Speaker not handling bass

[admin_exported]

Would appreciate some advice,

I have just purchased some Monitor Audio Bx2 speakers, they supposedly have 100 Watt rating however when I use my 60 watt amp to power them the songs with a lot of bass seem to make the speakers flap even at a third of the volume. Is this usual ? How can a 60 watt amp be too much for 100 watt speakers ? I am using spotify on my laptop to a separate DAC and through the amp if that makes any difference. All bass settings are default.

I'm a bit new to hi fi stuff so any help/advice would be much appreciated

 

[WinterRacer]

I would suggest it's because your amplifier is clipping and losing control of the speakers. What amp do you have and does it have a pre-out? If so, you could see if you can demo a matching power amp to see if that improves control?

Most people agree it's easier to overdrive speakers with a lower powered amp, my view is you can't have too much power!

 

[Frank Harvey]

Most amplifiers will be pushing out their maximum volume at the 12 o'clock position - after that, it'll definitely be adding distortion. Different music use different levels of bass - albums from the likes of Massive Attack are going to get your cones moving far more than say folk music or a string quartet. It's not that the amplifier is too much for the speakers, it's just that differing levels of bass may dictate the maximum volume you'll be able to push the speakers. Adding bass via the tone controls will help you reach that threshold more quickly.

 

[Anonymous]

i wouldn't have thought that any 60 watt amp would be losing control of a pair of easy to drive bx2's?

 

[WinterRacer]

You'd be surprised at how much power you need if you don't want your amp to clip with transients. It's something I'd like to see some kind of big question on.

Manufacturers such as Musical Fidelity and AVI have information about this on their websites. MF even have a tool that indicates how much power is needed for a given sensitivity of speaker. Other manufactuers seem to think it's something that's not particularly important. I've indicated my view on this

 

[rich51080]

I think watts is not the be all and end all of amplifiers.

Take my Naim Nap150x for example. 50 watts into 8 ohms yet it powers my B&W 705s beautifully without strain. and B&W are notriously difficult to drive. And they go extremely loud and make my windows shake.

Each Hifi brand have their own theory on watts, transformers and power supplies yet no one theory is a certainty.

Sugden who have amps at 25watts per Channel can shake a room with volume.

Personally I think a strong power supply is more important that wattage. Also Hifi amp makers test their products against a range of speakers so I would personally ask them what speakers they use for Synergy.

Naim may have only 50,60 or 70 watts yet can power speakers at ear piercing volumes.

I may email Naim and ask them for their reason why their amplifiers seem more powerful than the actual specs. It sure would be interesting.

 

[rich51080]

Would appreciate some advice,

I have just purchased some Monitor Audio Bx2 speakers, they supposedly have 100 Watt rating however when I use my 60 watt amp to power them the songs with a lot of bass seem to make the speakers flap even at a third of the volume. Is this usual ? How can a 60 watt amp be too much for 100 watt speakers ? I am using spotify on my laptop to a separate DAC and through the amp if that makes any difference. All bass settings are default.

I'm a bit new to hi fi stuff so any help/advice would be much appreciated

what amplifier are you using ?

The Monitor Audios are really easy to drive as someone previously said.

 

[aliEnRIK]

You'd be surprised at how much power you need if you don't want your amp to clip with transients. It's something I'd like to see some kind of big question on.

Manufacturers such as Musical Fidelity and AVI have information about this on their websites. MF even have a tool that indicates how much power is needed for a given sensitivity of speaker. Other manufactuers seem to think it's something that's not particularly important. I've indicated my view on this

I was reading a technical paper on this last week. Very interesting. A 'big question' would be cool.

 

[aliEnRIK]

Would appreciate some advice,

I have just purchased some Monitor Audio Bx2 speakers, they supposedly have 100 Watt rating however when I use my 60 watt amp to power them the songs with a lot of bass seem to make the speakers flap even at a third of the volume. Is this usual ? How can a 60 watt amp be too much for 100 watt speakers ? I am using spotify on my laptop to a separate DAC and through the amp if that makes any difference. All bass settings are default.

I'm a bit new to hi fi stuff so any help/advice would be much appreciated

'Flap' as in sound bad or just that they flap but it sounds ok? My MA silvers flap if theres serious bass, but not in a bad way

 

[Anonymous]

Thanks for all this info guys, definitly food for thought.

The amp is an old sherwood from the early nighties (was a hand-me-down), can't remember if it has a pre out and I'm not at home at the moment to check, if it did would you suggest getting a pre amp ?

From the reponses it seems you guys are suggesting I should try better quality amp, any reasonably priced recommendations ?

Just one other point to make, the sherwood amp was powering much larger but much older monitor audio speakers previously without a problem and they went very loud even with a lot of bass without any distortion although they did finally get toasted at a party when i wasn't there :-( seems strange that these new ones are having such a problem.

 

[Anonymous]

don't change your amp too fast, any budget amp should be able to drive bx2's..

 

[WinterRacer]

I was going to suggest adding a power amp and bi-amping your speakers, i.e., your existing amp driving the tweeters (easier load) and the new power amp driving the bass drivers.

However, to do this you need pre-outs and be able to get a power amp that matches your integrated. I think this won't be possible with your Sherwood.

If you're getting this problem on a regular basis at the levels you want to listen to, it's probably worth investing in a new amp of at least 100 watts.

 

[WinterRacer]

I was reading a technical paper on this last week. Very interesting. A 'big question' would be cool.

However, I have a bit of a problem with the Big Question. I'd like to see the Big Question taking a more scientific approach, for example, correlating what people hear with measurements.

For me, the Big Question doesn't answer questions, it just poses more.

 

[aliEnRIK]

I was reading a technical paper on this last week. Very interesting. A 'big question' would be cool.

However, I have a bit of a problem with the Big Question. I'd like to see the Big Question taking a more scientific approach, for example, correlating what people hear with measurements.

For me, the Big Question doesn't answer questions, it just poses more.

I completely agree. Though your 'never' going to get WHF to do that. So itll always be just a 'bit of fun'

 

[Andrew Everard]

Shall we try to stay on-topic rather than retreading the same argument again?

 

[WinterRacer]

I may email Naim and ask them for their reason why their amplifiers seem more powerful than the actual specs. It sure would be interesting.

I'll start by saying I've little experience of Naim amps and I'm not commenting on quality vs quantity!

What you need to consider is that the constant power that's required at normal listening levels is fairly low, however, for well recorded music, transients can require huge bursts of power if that peak is not to be clipped.

I would guess your Naims, although relatively low powered are good at short duration peaks.

 

[The_Lhc]

I was reading a technical paper on this last week. Very interesting. A 'big question' would be cool.

However, I have a bit of a problem with the Big Question. I'd like to see the Big Question taking a more scientific approach, for example, correlating what people hear with measurements.

BORING!

 

[Andrew Everard]

Again, back on topic, please...

 

[CJSF]

Not my field but, I noticed 'Spotify' was the source into a remote DCA . . . Is Spotify (MP3) clean enough, and could the DAC be having an effect? Perhaps, try by passing the DCA? may not help but at least it eliminates it as a potential problem????

My own 20w, 20 year old budget Rotel hand me down, of a scratch system, with remote DCA, is often driven by spotify. I know little of the 'Professional Monitor Co' LB1's I use, apart from; they do the business and no driver flapping.

Sorry, not sure how relevant the above is, just another angle???

CJSF

 

[rich51080]

I would trade your amp to something like an old Rotel - Build like a tank and will drive your speakers with ease.

You can buy for under 100 pounds and would be an investment worth having - I had rotel before Naim and they are brilliant.

Or a 90's technics would be good.

Also look out for Marantz or Nad - either would drive your speakers with relevant ease.

If you prefer power of detail and dynamics how about a behringer dj amp which can hurl out 200 watts a channel.

All depends if you want to trade clarity/detail for power. The trade off wont be huge IMO as long as you got a good source.

 

[lindsayt]

I think that it's highly likely that this is entirely normal behaviour for these speakers with this music at generous but not excessively loud volumes.

The amount of forward and backwards movement required from a bass cone for a given volume will depend on the square of the cone diameter. Double the diameter of the cone and it only has to move 1/4 as far.

I have a friend with Dynaudio speakers with similar sized bass cones to the bx2's. At moderate volumes with pop or rock music you can see the cones moving in and out - flapping about. I suppose this is what's called a modern long-throw mid-bass unit. If you're used to speakers with larger cones, this can look quite alarming. Play the same music at louder volumes through 15" bass cones and you won't see them move, but you can feel them vibrate if you touch them.

I bet you that changing the amp won't make any difference to the amount of cone excursion you're getting, unless the new amp has a leaner tonal balance - which is unlikely as the vast majority of amps have a flat frequency response give or take a db or two.

Your 60 watt amp should be good for 105dbs through these speakers before clipping. This is loud. You could buy, borrow or hire a sound pressure meter to find out how many dbs you're listening at.

How do the bx2's sound compared to your older and bigger speakers?

 

[jiggyjoe]

Would appreciate some advice,

I have just purchased some Monitor Audio Bx2 speakers, they supposedly have 100 Watt rating however when I use my 60 watt amp to power them the songs with a lot of bass seem to make the speakers flap even at a third of the volume. Is this usual ? How can a 60 watt amp be too much for 100 watt speakers ? I am using spotify on my laptop to a separate DAC and through the amp if that makes any difference. All bass settings are default.

I'm a bit new to hi fi stuff so any help/advice would be much appreciated

Is this flap a pop or thwack sound as it sounds to me like the bass drivers are hitting there end stops (excursion limit).

This has nothing to do with there thermal (voice coil ) power handling. You can drive a bass cone to its limits easily with music that has a lot of really low bass tones in it.

 

[Anonymous]

The old larger Speakers are 2/3 times the size and had a much more deep bass sound to them. I can definitly hear more clarity from the Bx2's which is great and why I bought them, I just don't want them to get popped like the old ones at a party because they can't cope with too much bass.

The noise from the BX2's when playing load music with bass is more of a thwack than a pop, but kinda sounds like the old ones do now after they have been popped.

 

[jiggyjoe]

The old larger Speakers are 2/3 times the size and had a much more deep bass sound to them. I can definitly hear more clarity from the Bx2's which is great and why I bought them, I just don't want them to get popped like the old ones at a party because they can't cope with too much bass.

The noise from the BX2's when playing load music with bass is more of a thwack than a pop, but kinda sounds like the old ones do now after they have been popped.

Try gently pushing the bass cones with your fingers either side of the dust cap with the speakers off or no input. It should move in and out nice and smoothly.

If you feel any grating / scratching sound you've overdriven them or fried your voice coil

 

[plastic penguin]

Thanks for all this info guys, definitly food for thought.

The amp is an old sherwood from the early nighties (was a hand-me-down), can't remember if it has a pre out and I'm not at home at the moment to check, if it did would you suggest getting a pre amp ?

From the reponses it seems you guys are suggesting I should try better quality amp, any reasonably priced recommendations ?

Just one other point to make, the sherwood amp was powering much larger but much older monitor audio speakers previously without a problem and they went very loud even with a lot of bass without any distortion although they did finally get toasted at a party when i wasn't there :-( seems strange that these new ones are having such a problem.

Yup, I've a fair bit of experience with Sherwood (what a confession). My best friend used own a few - no idea why - and they are pretty syrupy and struggles with better quality or harder to drive speakers. You need a change of amp IMHO. As others have suggested Rotel. Can't disagree with that... I'm a big fan. Alternatively, look at s/hand Marantz 7001, Kandy MKIII or LIII.
Or maybe any Arcam from the DIVA range.