BACKS TO THE WALL ?

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While researching for my next speaker investment, why is it that most speakers seem to requre free space too be at their best ? Surely with a majority of houses in the uk space would be of a premium. Bungs are supplied ,but frowned upon in certain circles on this forum and magazine staff.

ATC appear to be the only brand that get the majority vote on here that work well against walls ?

ROOM size is one of questions asked by the pro,s before recommending speakers,so why is it most speakers are designed to work in free space ?

:?
 

Frank Harvey

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Hello again FATS :)

I'm sure there'll be one or two replies appear by the time I finish this, so forgive me if I repeat anything in the meantime.

In a land that time forgot (70's), many speakers used sealed cabinets. One benefit of this was that bass was far more even, but the downside was a slightly early bass roll off, but some manufacturers got round that with bigger cabinets or bigger bass drivers - or both. A sealed cabinet could be placed fairly close to a wall with minimum boundary effect upon the sound, ideal for the UK's little rooms. Another downside was that sealed cabinets were inefficient, and needed more power to drive them.

Fast forward to the future, and attitudes to this solitudinal (is that a word? It is now!) pastime have changed. 'Other halves" no longer want large speakers in their living space, and dislike the ugly looks of much of today's functional designs. The 80's saw manufacturers moving away from inefficient speakers and using reflex ports, which aided efficiency, and also bass depth, by tuning them to a lower frequency than the speaker could physically reach, making bass sound much deeper than it actuall is. The downside was that reflex ports that were situated on the back of a speaker interacted with room boundaries, making a speaker sound even more bass heavy. The 90's saw slimline speakers taking over, and because they were using smaller drivers, relied heavily on reflex ports (sometimes multiple ports) in order to sound like they had any bass at all.

There have been very few sealed cabinet designs over the past couple of decades, but ATC seemed to have brough it back, and a few manufacturers like Spendor have some sealed designs in their line ups. ATC don't seem to mind the fact that their speakers need the National Grid to power them (exaggeration! Before the usual suspects pounce!), but most manufacturers want their speakers to be 'universal' - to be easily driven, and widely compatible for maximum sales. Having said that, there are many speakers on the market that have been designed for wall use, but still sound. Ether in free space anyway.

Ports, you could say, are generally bad things, and are used haphazardly in cheaper speaker designs. But that's not to say they can't be used properly to enhance a speaker's abilities. ATC use ports in their larger SCM models (50's, 100's etc), B&W in their 800 series, and KEF's Blade uses two ports (two sections to the cabinet).

Foam bungs are provided to reduce airflow through these reflex ports, but they usually end up sucking the life out of the speaker as well. Less dense foam bungs can work better in this respect, but don't usually keep the bass in check.

The room size thing is mainly down to whether a particular size speaker is able to fill that space efficiently, but this also depends on the amplifier's capabilities.
 

busb

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I suspect that it's a lot easier to make speakers work in free space than set in or against a wall. I also seem to remember reading that imaging suffers. However, I've been lent a pair of Gradient speakers that are designed to work this way. their imaging actually seems good & their bass is not lacking nor flatulent.

I would like decent sounding speakers that were suspended from walls rather than pieces of furniture taking up space just like CRT-based TVs did! I have a lot of time for the notion that AV should not dominate a room!
 
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Anonymous

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Hello david, Yes as soon as i pressed the save button i new i forgot to mention the ,[Other halves ] syndrom. I take it you have your tin hat at the ready ? ;) I,m sorry did i mention A _ C again :doh: . Yes i used to own a pair of wharfdale lintons [ life seemed much simpler then ] When men were men and not mice. What are your thorts on front loaded ports ?[looks like lodging an order with you soon pm1 shh wife,s listening] Now, where,s that cheese ?
 

Frank Harvey

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Mmmmmmm, cheese :)

A port is a port, and it does what it does, regardless of whether it's rear or front loaded, but obviously front ports have less effect on the sound of a speaker when it's placed near a wall. Personally, I'd have thought that most manufacturers would've come away from rear ports by now, but a rear port can exaggerate the desired effect the manufacturer is looking for, and it might be exactly what some bassheads are looking for too. Sealed cabinets and front ported ones are obviously more ideal and easier to accommodate, while rear ported ones really need room to breathe. As I mentioned though, even some speaker's that are designed for good performance near a wall, can sound better with a bit of space.

My dad had sme great big Wharfedales when I was a toddler, but I can't recall their look or model, only the logo, and the extremely textured, thick style of the very unacoustically transparent grille :)
 
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Can't remember the name of my dad's Wharfdales either, but they did have 15 inch bass drivers and were powered by Quad valve amps. My mates were mightily impressed by demos of Floyd plus Led Zep 1 & 2 back in 1969. If only I'd kept my vinyl - paid the price of early adoption to CD in 1984. I understand that the original Sticky Fingers with denim and Zip cover is worth a few bob these days!

Back to topic. How do front ported TL designs from PMC work close to a wall?
 

MattSPL

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I used to have a pair of PMC IB1's that had a front exit transmission line. These worked well close to walls. I think corners may cause issues as with any speaker, and imaging will suffer somewhat.

The main issue with being close to walls is boosting of bass. It may not cause too much bass for your needs/room, but it may cause uneaven bass, with certain bass notes sounding louder than others.
This may be hard to detect listeing to music, but if you insert a demo disc with bass tones, you will notice the volume level can vary alarmingly between different bass frequencies.
 

CJSF

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MattSPL said:
I used to have a pair of PMC IB1's that had a front exit transmission line. These worked well close to walls. I think corners may cause issues as with any speaker, and imaging will suffer somewhat.

The main issue with being close to walls is boosting of bass. It may not cause too much bass for your needs/room, but it may cause uneaven bass, with certain bass notes sounding louder than others.
This may be hard to detect listeing to music, but if you insert a demo disc with bass tones, you will notice the volume level can vary alarmingly between different bass frequencies.

Still got a pair of LB1's Matt . . . listening to them at this minute, 5ft off the floor on a shelf, 3ft apart and 9" from the wall in a 12ft square room with 9ft celling, they are doing a great job on Bach's fugue in D minor, teeth rattling stuff . . . They came my way in the late 80's. I had the choice of speakers in those days, they stood the test of time. So easy to position and drive? I might ad, doing the room up, so this will not be the final position . . . :D
 

MattSPL

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CJSF said:
MattSPL said:
I used to have a pair of PMC IB1's that had a front exit transmission line. These worked well close to walls. I think corners may cause issues as with any speaker, and imaging will suffer somewhat.

The main issue with being close to walls is boosting of bass. It may not cause too much bass for your needs/room, but it may cause uneaven bass, with certain bass notes sounding louder than others.
This may be hard to detect listeing to music, but if you insert a demo disc with bass tones, you will notice the volume level can vary alarmingly between different bass frequencies.

Still got a pair of LB1's Matt . . . listening to them at this minute, 5ft off the floor on a shelf, 3ft apart and 9" from the wall in a 12ft square room with 9ft celling, they are doing a great job on Bach's fugue in D minor, teeth rattling stuff . . . They came my way in the late 80's. I had the choice of speakers in those days, they stood the test of time. So easy to position and drive? I might ad, doing the room up, so this will not be the final position . . . :D

Lovely speakers CJSF :) Its a shame PMC don't make those anymore.
What amp are you using?

Cheers
Matt
 

CJSF

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MattSPL said:
CJSF said:
MattSPL said:
I used to have a pair of PMC IB1's that had a front exit transmission line. These worked well close to walls. I think corners may cause issues as with any speaker, and imaging will suffer somewhat.

The main issue with being close to walls is boosting of bass. It may not cause too much bass for your needs/room, but it may cause uneaven bass, with certain bass notes sounding louder than others.
This may be hard to detect listeing to music, but if you insert a demo disc with bass tones, you will notice the volume level can vary alarmingly between different bass frequencies.

Still got a pair of LB1's Matt . . . listening to them at this minute, 5ft off the floor on a shelf, 3ft apart and 9" from the wall in a 12ft square room with 9ft celling, they are doing a great job on Bach's fugue in D minor, teeth rattling stuff . . . They came my way in the late 80's. I had the choice of speakers in those days, they stood the test of time. So easy to position and drive? I might ad, doing the room up, so this will not be the final position . . . :D

Lovely speakers CJSF :) Its a shame PMC don't make those anymore.
What amp are you using?

Cheers
Matt

Hi Matt, see thread: 'Guidance please' . . . it will give you an idea of the turmoil and frustration I am going through . . . The amp is an old Rotel 820, I bought it for my Father around 1990, he loved his music, loved it for its own sake, sadly, he died in 2000 . . . put the amp in the loft. After 15 years of me not listening to any music, I dug it out a few months ago, discovered a musical gem? Some of the rest of the story has been told in bits in the forum . . . it is pure frustration!!!

CJSF
 
FrankHarveyHiFi said:
Ports, you could say, are generally bad things, and are used haphazardly in cheaper speaker designs. But that's not to say they can't be used properly to enhance a speaker's abilities. ATC use ports in their larger SCM models (50's, 100's etc), B&W in their 800 series, and KEF's Blade uses two ports (two sections to the cabinet).

ATC don't use ports to increase LF. Instead they use the resonant frequency of the port and tune it to the lowest octave of the speaker. This not only helps to limit the excursion of the bass driver but also reduces mechanical distortion. With this ATC are effectively providing the bass driver with a loading which is equivalent to a closed box design.
 

Frank Harvey

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I'm not saying they do. All I'm getting across is that while many loudspeakers out there use ports to 'deceive', there are high end models that utilise ports properly, without the drawbacks and issues usuallybassociated with them.
 
FrankHarveyHiFi said:
I'm not saying they do. All I'm getting across is that while many loudspeakers out there use ports to 'deceive', there are high end models that utilise ports properly, without the drawbacks and issues usuallybassociated with them.

If you had known this then there wouldn't have been any need to bring ATC into this as (i mentoned in my previous post) they don't use speaker ports in the conventional manner.

Btw, i take it that from now on you won't be recommending too many non high end ported speakers as these designs don't do the job properly and instead 'deceive'.
 
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:shhh: So as long as a port is designed properly to intergrate correctly into the speakers sound, and not added too cut corners in costs, there is not a problem ?
 

AEJim

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FrankHarveyHiFi said:
Ports, you could say, are generally bad things, and are used haphazardly in cheaper speaker designs.

Bit of a blanket statement there David, care to name any examples? Ports are useful in many ways and cheaper speaker designs often take more effort to get right than expensive ones since you're more limited by size, engineering and materials.

Ports may be seen as evil, noisy things by some but they greatly increase efficiency to take the strain off of weaker amps and in smaller cabinets help to extend low frequency roll-off by 10-15hz. They are rarely used by credible manufacturers as a kind of "bass boost".

Ports also often are used at the rear for two reasons - 1: baffle size, in order to fit a port on the front a speaker would often have to be made larger which isn't always acceptable when size is a design factor. 2: You hear quite a large amount of midrange and internal resonance from a port so in order to stop it interfering with timing and fine detail it's best to fire that away from the main driver output facing the listener. You can test this on rear ported speakers pretty easily by facing both closely together out of phase and listening to the sound that comes out of the ports.

In an ideal world with space and power not a factor, all conventional cabinet speakers would probably be sealed box for clean response but then we'd have to have far larger cabinets to make up for the loss in low bass and accept around 3dB efficiency loss - for some this is fine but for others it's not acceptable. Both design ethos' have their benefits and they're not necessarily price or quality related.
 

Frank Harvey

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Hence the use of the word 'generally'.

If electronics manufacturers made more powerful amplification, and more affordable, then speaker manufacturers wouldn't have to worry about having to use ports on certain designs - they'd have free reign to make a quality speaker without compromise. Or less compromised, shall we say.

Smaller speakers probably need rear facing ports, but on speakers with room on the front baffle - which is the majority of them - there no excuse not to use that spare space.

I'll repeat - when a port is designed properly, it's advantageous.
 
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SO two questions.

1. Has the port in b&w pm1 ,s been designed ,in a positive way ?

2. IF A .. C. incorporated a small well designed port in the 11,s /19,s

would this help in higher sensitivity / i,e easier to drive.

And maybe a more acceptable sound to some with low level listening issues?

WAIT for it . :)
 

BenLaw

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Hi Fats 2828,

I don't think '2' is going to happen somehow ;) I suspect that ATC (unlike David) do not consider that there is a problem driving their entry series speakers, and would not wish to sacrifice the current quality in the speakers by changing the design. Your post obviously envisages a change in the sound of the speaker, but ATC are known for the tonal consistency throughout their ranges, and I can't imagine they would want to change this through the addition of a port.

Cheers,

Ben.

Edit: another way to put my view would be, 'if it ain't broke, don't fix it' :)
 

BenLaw

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FrankHarveyHiFi said:
If electronics manufacturers made more powerful amplification, and more affordable, then speaker manufacturers wouldn't have to worry about having to use ports on certain designs

Although surely more powerful amplification would not be a complete solution to the problem (for bass reproduction) that you identified in your first post of smaller bass drivers?
 

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