Does size matter?

James,

Lots to consider in your question. The simple answer is the larger the cone area the more low frequency energy the loudspeaker can generate. Whether this is by a single large cone or multiple smaller cones is not critical. This is generally more applicable to sealed box loudspeakers. Ported or transmission line enclosures extend the low frequency response by outputting the back wave of the loudspeaker via the port or transmission line opening.

Another factor is the size of the loudspeaker enclosure which affects the cabinet fundamental resonant frequency and low frequency output.

Sealed enclosures have a more gentle low frequency roll-off than can give the impression of greater low frequency extension. 

It is important to distinguish between the quantity and quality of low frequency reproduction. For some rooms a more restricted low end is better than one that is more extended.

I used to use Martin Colloms book High Performance Loudspeakers in my Electro-Acoustics class. A good read.

and then there's isobaric design 

I can get Kans here to have more slam and bass impact than most speakers i've had. Your Credo's are IMO a little loose in the bass, but PMC's would not ever be on my radar after living with speakers that play tunes, which in your case, the Credos do nicely.

No. Stroke length is important.

or it does when it comes to volume of air displacement.

old speakers had large cones/small cone movement.

modern speakers have smaller cones/large cone movement.

JamesN posted:

Hi all and happy bank holiday weekend! (In the uk)

I have a question that has been nagging me for some time, and it is down to the size of speakers...not necessarily cabinets but more on the driver size.

My confusion came years ago when I was running an Arcam system with Kef Q60's inherited from family. Due to my at the time girlfriend not liking the look of them, I opted to purchase their much newer successor; the IQ3's. These had a 6.5" cone as opposed to the larger 8" cone in the Q60's.

Whilst there were some improvements in detail etc, I really missed the slam and depth of the predecessors. So much so that I have never bought a pair of speakers with a small cone since. For example the rumble right at the end of 'Run like Hell' on Pink Floyd's 'Pulse' wasn't anywhere near as exciting!

I now have Naim Credos which have an 8" cone but I have been looking lately at PMC and Proac's offerings and have been wondering what they are like in the bass depth arena, as they all seem to employ far smaller drivers than that I'm used to.

I guess my simple question is...does size matter if you want full deep bass?

Thanks!

James

Simple answer: yes :-)

You're making me feel distinctly inadequate with my just shy of 6" Kudos X2s. Aesthetically, I'm not keen on moving on to anything bigger, so I decided to cheat and hide an N-Sub behind the sofa. That was a good solution with my Superuniti. Since moving on to NDX/282/200DR, I have yet to reconnect the sub, as it requires different cabling which is going to be a bit fiddly, but the bass is so much improved now that I'm wondering if I can live without the sub. It was the final addition of the 282 that allowed the extra bass (amongst other things) through and helped to show what the speakers are capable of.

Yes it does

However the bigged the diameter of the woofer cone, the more power is required to move it and to generate a proper, loud enough bass wave.

So as usual a co promise is somehow needed.

In my live bass rig, the biggest speaker is 15" in diameter, but to get some clarity I also need 10" speakers + some high-frequency horns centered around 4-5 kHz (this is where attack of a bass guitar resides). Power comes from a 600W tube/mosfet amp wich also produces sub-harmonics (down to 20 Hz or so). The acoustic preasure can be so high it can damage closed windows.

Of course a set up like that would be utterly impractical for a domestic environment.

The reason for the above ramblig is as follows - go and figure out how to replicate a bass rig, in full swing, so that it sounds good on a home system 

Except high efficiency speakers with big cones that can be powered by 6 watt tube amps...,

gary yeowell posted:

Except high efficiency speakers with big cones that can be powered by 6 watt tube amps...,

Very true

I don't know what it is, but there seems to be something really right about an 8" unit paired with a tweeter. These solutions seem to be very successful to me generally speaking.

Frank.

Blimey one dinner out and you miss a lot here! Thanks everyone for your input, and all very interesting.

I'm still unsure as to why Kef went for the smaller driver as when pushed to higher listening levels, the older speakers still sounded very composed, but the newer smaller speaker distorted. To my ears, they created an inferior speaker.

I guess aesthetics do come into things, as the average person would probably prefer a smaller bookshelf speaker than something similar to the Spendor BC1, and it is probably unfair to judge £2000+ speakers like Proac's by the sonics of a £400 speaker like Kef. But I can't help but wonder why smaller cones are used in almost every new speaker, when something slightly bigger may give a richer, fuller sound.

I understand that sensitivity comes into things but an 8" driver can be powered very easily with small amps.

By the way I am no expert on any of this and am probably wrong on this, but just an observation!

James

Totally agree Frank. I seem to be drawn to them more than anything else.

I think it will be extremely hard for any 6 inch main driver to come even close to the one Naim used in the Credo.

Why in that case would so many big high end brands like PMC/Proac/Totem etc insist on using them? I would really like to update my speakers but still retain the scale of sound that im used to.

JamesN posted:

Why in that case would so many big high end brands like PMC/Proac/Totem etc insist on using them? I would really like to update my speakers but still retain the scale of sound that im used to.

Maybe the associated smaller baffle area fits more with a contemporary interior design aesthetic.

C.

I think the move to smaller drive units is pushed by the aesthetic appeal of narrower baffles. Actually, that's not entirely all - there are benefits to narrower baffles because the baffle resonates less and is easier to manage. It's also a lot easier to manage multiple units in the baffle because the energy is less. However, the aesthetic value of a narrow baffle, not having big boxes to look at, is also very prevalent. Slimline speakers appear more elegant to many, and so fit in with the modern aesthetic more readily.

So in order to get around the smaller drive unit surface area, manufacturers have developed long throw drivers as mentioned by fatcat. In theory the long throw driver moves the same volume of air as a larger drive unit that moves less. Comparisons are difficult to achieve fairly because the entire design of the two speakers is necessarily different for each drive unit to work correctly. However, my experience tells me that there can be a lack of slam or attack with smaller drive units, and at the same time the 8" system still has the delicacy and speed of a 5 or 6" based system. 

These are all compromises of course, and some are better than others, but I do feel that 8" systems work really well. 

Frank.

JamesN posted:

Why in that case would so many big high end brands like PMC/Proac/Totem etc insist on using them?

Not sure but I suspect it's all part of a package like a 2.1 system (ultimately) for instance.

Size does matter but its not just the driver, it needs cabinet volume as well,  hence the classic old timers the big horn Tannoys that IMO are still the ones to beat,  but who has the room to fit them in.  

That said it easy to knock small(er) 6" (150mm) bass drivers, but in the average domestic sized room the narrower cabinet that a 6" presents is more suited. Modern drivers, materials & design have advance significantly in the last 10 or 15 years, & whereas the old 8" paper cone that was almost the only way to get a resemblance of bass in the smallest possible cabinet,  now modern drivers go lower & do it better & a 6" does all thats needed.  Most important is they do a good job for most people in the average size room, PMC, Neat & Kudos sales must show the 6" works & I don't hear too many complaining about bass from the SCM19.   I built my own using a 6" (150mm) Scanspeak,  very expensive I have to say,  but with an FS of 30Hz it does deliver remarkable bass for its size that is both deep & tuneful.  For sure miles better than my old 8"ers .    

Christopher_M posted:

Maybe the associated smaller baffle area....

*narrower*

C.

Mike-B posted:

 I built my own using a 6" (150mm) Scanspeak,  very expensive I have to say,  but with an FS of 30Hz it does deliver remarkable bass for its size that is both deep & tuneful.  For sure miles better than my old 8"ers .    

Time to see if you can borrow a pair of Credos, SBLs or SL2s, Mike!

C.

I have Chris, listened to both the SBL & SL (in others homes) but not Credo - Nice but no thanks,  with all the Naim speakers I've listened to I hear the tailed off low end to suit wall placement & biased to the top end.  Yes I know the rest of the world will now condemn me as unworthy,  but it just does't work for me.   (BTW my old 8"ers were Epos ES14)

I understand the comments above, but it has always confused me how earbud speakers or headphones can reproduce low bass notes with their relatively tiny drivers compared to normal loudspeakers. How does this work - is there a relationship between frequency and amplitude so that tiny drivers can still generate low frequencies but just at low volumes ?

Mike-B posted:

I have Chris, listened to both the SBL & SL (in others homes) but not Credo - Nice but no thanks,  with all the Naim speakers I've listened to I hear the tailed off low end to suit wall placement & biased to the top end.  Yes I know the rest of the world will now condemn me as unworthy,  but it just does't work for me.   (BTW my old 8"ers were Epos ES14)

Not from me. Experience always valued over conjecture.

C

my old Totem Mani2s go down to 29Hz with 7in Dynaudios in an 8.5in baffle, but hold the unfair advantage of isobaric config

Ok, very interesting! Thanks for all of the contributions.

If I wanted to buy a larger speaker with an 8" driver, does anyone have any suggestions around £2k-ish?

I can't seem to find any brands that cater for this market. Most go for the slimmer cabinet with a smaller driver unfortunately!