speakers frequency range

[Dartas]

Hi guys,

can some one please explain how the anounced frequency range from a speaker relates to its size?

My main doubt is, can a Q-acoustics comcept 20 (smal standmount) with a frequency range from 63 hz produce more and deeper bass than a b&w cm8 (floorstander) who can only go down to 69hz?

[Macca]

It is not just the frequencey response range you have to consider it is at what level the output is. A speaker may go down to 30 Hz but if that is at -15dB compared to the mid and top you are not really going to hear much ouput. Conversley a speaker that goes down only to 50 Hz but which is 'flat' at that level i.e 0dB of difference compared to the mid and top will sound like it has a lot more bass than a speaker that is say 10dB down at that level.

Manufacturers like to quote as low a bass response as possible because they know it is a stat that people look at when considering a purchase but it does not neccesarily convert into the real world when playing music.

Depending on how they are voiced a speaker with a large internal volume can sound bass light compared to one with a much smaller volume but its bass will likely be of a better quality - that is it will reproduce the actual sound of the bass instrument rather than just a low frequency tone.

[Beobloke]

As above. The B&W website states that the CM8 is within +/-3dB to 69Hz but has a -6dB point of 43Hz, whereas although the Q Acoustics website states a lower frequency point of 64Hz, no clue is given as to what the dB limits of this are.

If bass is your main concern then go with the floorstander. Whilst some small boxes do surprisingly well at the low end, unfortunately you're always up agains the laws of physics, ultimately.

[Dartas]

Thank you guys.
Some great explanations here..

Martin if it's so, than is almost impossible to analize just from the specs if a speaker will do good in bass or not, isn't it?

[DSJR]

Can I add that bass *damping* in the amp (to a degree), cabinet and drive unit, let alone the type of crossover used, can have a huge effect on how bass is perceived in a given room and of course the listening room itself can make or break any given speaker...

[Macca]

Thank you guys.
Some great explanations here..

Martin if it's so, than is almost impossible to analize just from the specs if a speaker will do good in bass or not, isn't it?

Yes. You can get a general idea but there is no substitute for trying the speakers in your system and in your room. Plus on top of all that if the speaker presents a difficult load to the amp that will also affect bass performance if the amp cannot deliver enough current to deal with it.

For a box loudspeaker if you aim for as big a bass driver as possible in as big a cab as possible you won't go far wrong ;)

[Rothchild]

and of course the listening room itself can make or break any given speaker...

Axial modes are a killer, you can forget a nice +-3dB response on your speakers when your room dimensions are cutting and boosting ~15dB at selected frequencies, roll your chair back and forth and it's like someone winding the eq on the amp up and down! Cuboid rooms are the worst and the sort of size rooms you get in UK domestic living spaces tend to mean that there's a whole world of horrors going on in the low and low mid range.

These simple physics also apply to the amount of bass a speaker can make (and how low it will go), it can be faked with porting (esentially turning the speaker in to a tuned pipe) but IMO it's never as satisfying as what you get from a good transmission line or, better still, a big sealed box with huge drivers.

[Dartas]

Dahhm, this is harder than i tough :doh:

My problem is actually very specific.. I had some floorsatnders (Focal 714) and i was having too much bass overkilling the medium and high frequencies, so i sold them and bought some Concept 20, but now i have great mids and highs, but i feel it lacking in lows... I have lows, but i actually miss the impact and the really low frequencies, so i will change again, now my question is; should i go for a bigger standmount or just a smaller floorstander??

Decisions decisions :scratch:

[Dartas]

Axial modes are a killer, you can forget a nice +-3dB response on your speakers when your room dimensions are cutting and boosting ~15dB at selected frequencies

And how do you calculate that (if it is even possible)?

[Rothchild]

And how do you calculate that (if it is even possible)?

Yeah it's possible, there's any number of calculators online, like this one: http://www.marktaw.com/recording/Acoustics/RoomModeStandingWaveCalcu.html put your room dimensions in and it will tell you where in the frequency spectrum the nulls will be, in all three dimensions. If you've got a cuboid room then you're going to end up with the same number in the middle of the room so you'll have a massive dip (and probably a corresponding massive peak at a different frequency in the same spot).

Edit: I just noticed you're in Spain, hopefully the dimensions of your rooms aren't what they tend to be in the UK! (although any room will have a standing wave response).

[YNWaN]

Thank you guys.
Some great explanations here..

Martin if it's so, than is almost impossible to analize just from the specs if a speaker will do good in bass or not, isn't it?

Yes and no would be my response ;). The theoretical range of human hearing is 20Hz to 20,000Hz (20K). Most speakers will produce some output across that entire range - even small ones. However, as others have said, they will not be flat across the frequency range. Most manufactures quote the lowest cutoff as being -3dB below flat because that is generaly considered a significant level reduction (the speaker will still be attempting to reproduce lower frequencies but they will be at too low a level as to make any real contribution) - but some quote a -6dB point and some are just rather optimistic with their figures.

Frequency range measurements do give an idea of the lowest frequency a speaker can play flat to but in subjective terms (actually listening to music) it's not very relevant. The measurements give no clue as to the actual bass quality, just the quantity when playing a test tone.

[YNWaN]

...should i go for a bigger standmount or just a smaller floorstander??

Decisions decisions :scratch:

Neither - consider a sub-woofer with built in amplifier and active crossover. You can then position and adjust this to suit your room (BK, REL etc.).

[mr sneff]

Dahhm, this is harder than i tough :doh:

My problem is actually very specific.. I had some floorsatnders (Focal 714) and i was having too much bass overkilling the medium and high frequencies, so i sold them and bought some Concept 20, but now i have great mids and highs, but i feel it lacking in lows... I have lows, but i actually miss the impact and the really low frequencies, so i will change again, now my question is; should i go for a bigger standmount or just a smaller floorstander??

Decisions decisions :scratch:

If you like the mids & highs of the Concept 20s couldn't you just add a sub or subs?

[kininigin]

This is what i have done,which is add a sub to my standmounts.The standmounts on their own are pretty good through the frequency range without the sub.But ultimately was never giving truly deep,extended bass! Which is required for alot of music i listen too.Since adding the sub,it's been a revelation.

If going the sub route,i would suggest a sealed type that is suited for music replay,rather than home theatre!

[Dartas]

I do have a subwoofer (REL T5), but i never came to love the sound with sub because to my ears the bass allways sound a bit artificial.
Maybe i just didn't integrated it well with the speakers, but still like it more without the sub...

[Macca]

You've got a good sub there you should be able to make it work. The usual problem with subs is tuning them too high up. For rock music you really shoud barely be able to tell if the sub is on or off. For electronic/dance/organ music you should notice the difference when you turn the sub off whilst music is playing. If you didn't already try it then set up with the sub coming in at 45 Hz and down, set the volume at about 70% of max and then work downwards. If the sub sounds 'obvious' then you either have it cutting in too high or on too high a volume level. Or both.

[YNWaN]

These days the siting advice that Rel give is very much aimed at the AV market and maximising room loading - i.e. to use room boundaries (walls & corners) to load the bass. Doing such gives really big bass but makes it hard to integrate with free standing speakers. It's also worth considering that it is very easy to set the crossover frequency and the level too high - relative phase at crossover point will also make a significant difference to integration.

[Reffc]

The whole quoted frequency response thing can be very misleading, and as a result, very confusing.

Initially, forget the room issues, as what you are trying to establish is a comparator between loudspeakers. Your room will have a similar effect on frequency loading irrespective of the speaker used.

It is fairly commonly accepted practice for manufacturers to quote a response at -6dB these days (more so than -3dB) because 6dB happens to be the baffle step loss for almost all small standmounts and narrow baffle tower floor standers. The 6dB isn't lost, but at the baffle step, wraps round the speaker from a 2 Pi radiating pattern (ie towards the listener) to 4Pi space (ie 360 degrees) and whilst the total radiated bass energy remains in the room, direct radiated SPL anechoically is down 6dB. Place speakers close to a wall and you regain this 6dB back as the sound reflects off the rear wall, hence the -6dB point quoted.

It's not always that simple though, as it doesn't tell you about the quality of the bass. Many speakers will make a noise at say 40 to 50Hz but few make a decent stab of real bass texture, low group delay and good phase accuracy. These are more complex parameters which go beyond common comprehension for most buyers and the quality thing itself can only be conceptualised by listening.

Also, the full frequency response is often quoted on axis, when many people listen off axis, so the 30 degree off axis figure is a more appropriate measure unless speakers are toed in.

It's a bit of a minefield and that's before things like impedance curves and more importantly (for many) phase response are considered. The latter is a good measure of how a speaker "times" if you like, between drive units. That is usually a function of a combination of effects from crossover design, chosen drive units and cabinet design.

[Barry]

Good post Paul! :)

[Firebottle]

+1 to that.
Such knowledge in depth is a joy to read.

Alan

[icehockeyboy]

Dahhm, this is harder than i tough :doh:

My problem is actually very specific.. I had some floorsatnders (Focal 714) and i was having too much bass overkilling the medium and high frequencies, so i sold them and bought some Concept 20, but now i have great mids and highs, but i feel it lacking in lows... I have lows, but i actually miss the impact and the really low frequencies, so i will change again, now my question is; should i go for a bigger standmount or just a smaller floorstander??

Decisions decisions :scratch:

Just buy a sub. :)

Just read the rest of the posts.....you already have one!