Speaker Oddity

[Glassman]

Runing Linn Akurate 242 from bridged amplifiers; source: mainly CD, occasionally turntable. The speakers sound lovely and don't present any issues until that is, the bass notes are a bit 'punchy'.

If I'm playing Floating Points, Cinematic Orchestra, Pink Floyd live; Nils Frahm, Nicholas Javr, Khruangbin for example: great. But playing something a bit more upbeat like Bicep, Ross From Friends or Four Tet, if I'm not careful the bass can make a popping noise (sound more like a 'pap' than a pop). I've switched the amplifiers and it's the same. Nothing else suggests there's an issue with the speakers (which are as mint as the day I bough them from Ripcaster).

Could there be a driver/technical/hardware issue or is it the type of music? I'd like to explore a bit of self diagnosis for educational purposes before calling in a specialist.

[Digger]

From both speakers, more often than not in unison? Or sometimes the left & sometimes the right?

[Glassman]

I think both, but not in unison.

[Panamax]

Are you using the "bass boost" connection terminals?

Are you using the "bass bungs" in the rear ports?

"They come with foam bungs to block their two large-diameter rear-firing ports should bass become too much, and these do as advertised – but the 242s really need a free space to perform at their best."

[theboss]

I’d wonder if the bridged configuration had anything to do with it. Not from experience or from any technical know-how, just the fact I’ve had and used umpteen Linn systems over the years and it doesn’t seem to be the done thing. E.g. I drive a pair of passive Akubariks (5-way with 3k array so similar configuration to your 242s) and use all 4 channels of an Akurate 4200 in a bi-amped configuration.

What amp(s) are you using? If its all Linn and/or supplied by ripcaster I would certainly go back to them as well.

There are also some good linn users groups on facebook with some very knowledgable people.

[Glassman]

Ports are open although I did try stuffing them shut with microfibre cloths. The other challenge I have is the bass throw. They're not in a small room but perhaps not big enough for them. There's no carpet (wood floor). They also back into a bay window (I can't place them anywhere else).

[Glassman]

theboss said:

I’d wonder if the bridged configuration had anything to do with it. Not from experience or from any technical know-how, just the fact I’ve had and used umpteen Linn systems over the years and it doesn’t seem to be the done thing. E.g. I drive a pair of passive Akubariks (5-way with 3k array so similar configuration to your 242s) and use all 4 channels of an Akurate 4200 in a bi-amped configuration.

What amp(s) are you using? If its all Linn and/or supplied by ripcaster I would certainly go back to them as well.

There are also some good linn users groups on facebook with some very knowledgable people.

Rotel amps.

When I was active (no pun) on FB, I did join what seemed to be the busiest Linn group. But I am on a self-imposed gag on FB; I only exist because I have a business page. I can't be dealing with the navel gazing and misinformation on display; it got to a point where even the select groups you interacted with were still at it in their own way.

[Panamax]

Glassman said:

Ports are open although I did try stuffing them shut with microfibre cloths. The other challenge I have is the bass throw. They're not in a small room but perhaps not big enough for them. There's no carpet (wood floor). They also back into a bay window (I can't place them anywhere else).

Interesting. The reason I asked is the only time I've had speakers deliver anything resembling the situation you describe is when the cones have been hitting their end-stops, which will be at a high level of bass/volume. That effect can be limited by either putting less electricity into the coils (turning down the volume/bass) or (b) making it physically harder for the cones to move (air pressure by blocking ports). If you've watched a large 'speaker in action the cones have to move a long way to deliver deep bass at significant volume.

How "loud" are things when you encounter this issue?

One of my things is that with large speakers and big amps you're listening to the "room" just as much as you're listening to the "gear". Carpets, curtains and soft furnishings can make a big difference. You get a similar effect in venues, which often sound completely different once the warm and squishy audience arrives.

[ben_eunos]

post a recording of the noise.

i'm no expert but maybe it could be:

- clipping or driving the speakers too hard
- something going wrong on the amplification side
- damaged drivers or surrounds

why not try a process of elimination, disconnect the bridged amps, and if you have one available, run it from a regular integrated amp and see if the problem persists, or otherwise, just off one amp, without briding etc (assuming those amps can be run in stereo and aren't e.g. monoblocks).

[Lucid_AV]

Glassman said:

Runing Linn Akurate 242 from bridged amplifiers; source: mainly CD, occasionally turntable. The speakers sound lovely and don't present any issues until that is, the bass notes are a bit 'punchy'.

If I'm playing Floating Points, Cinematic Orchestra, Pink Floyd live; Nils Frahm, Nicholas Javr, Khruangbin for example: great. But playing something a bit more upbeat like Bicep, Ross From Friends or Four Tet, if I'm not careful the bass can make a popping noise (sound more like a 'pap' than a pop). I've switched the amplifiers and it's the same. Nothing else suggests there's an issue with the speakers (which are as mint as the day I bough them from Ripcaster).

Could there be a driver/technical/hardware issue or is it the type of music? I'd like to explore a bit of self diagnosis for educational purposes before calling in a specialist.

The noise you're describing does sound like a description of the drivers bottoming out. You'd associate that with playing at high volumes, right? But it doesn't have to be the case. The right sort of signal can make this happen at modest volumes. I think that fact that it happens with some recordings but not others is part of the clue. This is a music signal issue, and the issue is subsonics.

Back to when vinyl was the main quality source, a lot of amps, pre-amps and receivers had a subsonic filter. Most people couldn't tell what it did until that played a warped record. The undulation of the surface caused the creation of a very low frequency - below hearing threshold - audio signal that would sometimes make it through to the speakers. How much of a problem this was would depend on the system; was it capable of passing or reproducing sound below about 30Hz, and were the speakers the sort that would react very noticeably to this signal? The type of speakers that were most at risk were bass reflex ones, but most speakers up to the early/mid-80s were sealed box.

Sealed-box (infinite baffle) vs ported: With a sealed box design, the air pressure inside the box balances the air pressure outside. Whether the cone moves in or out, the combination of internal and external air pressure tries to push the cone back to its neutral position. The air is an acoustic spring. So far so good. Then along comes bass porting. Suddenly it's possible to get a lot more bass from a speaker box of the same dimensions as a seal box. The speaker is more sensitive too; more sound from fewer Watts. The catch is that the bass port stops working below its resonant frequency, and the air inside the box no longer acts as a sort of acoustic suspension. The hole now becomes a way for the air inside the box to move in and out. (This doesn't happen above the resonant frequency. The port acts more like blowing over the top of an empty bottle. The air inside the cabinet stays there, mostly.

The upshot of all this is that the speaker cone flaps about quite a bit at frequencies below the port resonance frequency. If you cue vinyl, and then see the cones move a lot at the stylus makes contact with the disc, than this is what's happening.

Recorded music and the gear we use has evolved since the 80s. Lots of speakers are now bass reflex. Amplifiers have frequency ranges from 10-50k Hz. Electronic music makes it possible that artists include very low frequencies in their tracks for when they're played in clubs or on systems capable of reproducing very low bass.

Home cinema sub users sometimes need subsonic filters for their subs because low frequency effects can go down to 2Hz(!). We might be heading towards a point where the subsonic filter could become a useful tool again for stereo systems too.

There's more about this on the Steve Hoffman forum: https://forums.stevehoffman.tv/threads/in-line-sub...

[OutInTheShed]

Playing kids' music on old men's kit.
Those bass drivers are too small to pump the air at low frequencies and high power.

[Panamax]

Lucid_AV said:

The noise you're describing does sound like a description of the drivers bottoming out. The right sort of signal can make this happen at modest volumes.

Great summary post. As you say, CD played through a hefty amp into good speakers can deliver remarkable bass. Gary Numan's album - Savage, Songs From A Broken World - is just one example.

Also, the Steve Hoffman forum is a fantastic place to explore which music sounds best. Lots of comparisons of different pressings and remasterings of both vinyl (not my thing) and CD. A well made CD can be an astounding thing to hear through a big hifi.

[ben_eunos]

OutInTheShed said:

Playing kids' music on old men's kit.
Those bass drivers are too small to pump the air at low frequencies and high power.

moronic comment

[OutInTheShed]

ben_eunos said:

OutInTheShed said:

Playing kids' music on old men's kit.
Those bass drivers are too small to pump the air at low frequencies and high power.

moronic comment

Fundamentally, I think Linn thought long and hard about what a speaker system needs to do, and certain aspects of certain music were well outside the parameters.

It's basic that to make a lot of low bass, you need to move a lot of air and that means either a big transducer moving a fair distance, or a moderate sized transducer with an excessive displacement.

https://physics.stackexchange.com/questions/351552...

[Panamax]

OutInTheShed said:

Fundamentally, I think Linn thought long and hard about what a speaker system needs to do, and certain aspects of certain music were well outside the parameters.

I suspect that's fair comment. My own perception of Linn is very much "classical music" angled towards their "vinyl" heritage. The rock and blues crew probably tend to shop elsewhere. [Kudos speakers in my case.]

It's also worth mentioning that a big, modern amplifier can give any speaker one hell of a work-out.

[theboss]

These speakers were never the most bass heavy but are capable of sounding very convincing, they were about £7.5k 15 years ago and sold in the context of a system costing several multiples of that with amplification being a major component of that especially as they were designed to potentially be driven by 10 channels. They stand up pretty well in reviews.

I would certainly focus on the amps.

“Old mans” music can involve moving just as much air as contemporary stuff.

[OutInTheShed]

theboss said:

These speakers were never the most bass heavy but are capable of sounding very convincing, they were about £7.5k 15 years ago and sold in the context of a system costing several multiples of that with amplification being a major component of that especially as they were designed to potentially be driven by 10 channels. They stand up pretty well in reviews.

I would certainly focus on the amps.

“Old mans” music can involve moving just as much air as contemporary stuff.

Fair comment.
Friend of ours plays the bassoon. Another the bari sax.
I know what a cathedral organ feels like.

You can do the maths and understand that as the frequency reduces and the wavelength increases, a big woofer needs to move further to put a certain amount of sound power into the air. A smaller driver needs to move further still. Maybe that's one for the Rishi Maths thread?

I think a lot of 'current' music is engineered/produced/mixed to sound good with serious subwoofers and will find the limits of a good system with fairly small drivers, if the volume is turned up. There isn't AFAIK a clear lower frequency limit to what people should expect on e.g. a CD?
Fundamentally, speakers don't work at DC, there has to be a cut off. Otherwise we'd have bassheads giving themselves terminal barotrauma.