who has a sub?

[7_V]

Originally posted by titian
Just don't forget as I wrote somewhere before that every driver which is bigger than 12" 'break up' the cone. This means that when looking with a strobe light, the cone doesn't move up and down as a unit. You see waves in it. Especially very light cones break up and this makes lot of distortions. But this makes some colouring which is though very appreciated by lot of people.

I am an advocate of smaller, high excursion, low-distortion bass drivers.

The main reason that I use 8" drivers is because they require a smaller box and can be used in a modular fashion. The 8" driver used has more excursion capability and lower distortion than many 12" - 15" drivers, so four of them could go in an 80 litre enclosure and be the equivalent of a single 16" driver (and move as much air). Also, the cabinet vibration can be dramatically reduced using multiple smaller drivers.

However, in fairness, it's very unlikely that a well designed 12" or 15" bass driver will exhibit much cone break-up at the sub frequencies we're discussing, although there may be some flexing.

Cone break-up has received some bad press but it's not always as negative as its name implies. At bass frequencies you want the cone to act as a rigid mass, because even a small amount of flexing in the cone could lead to a less well-defined bass sound. However, at high frequencies, if the cone moved as a rigid mass, the sound emitted would become more and more beamy (directional) as the frequency increased, until you'd need to hold your head in a vice to get decent treble. Controlled break-up looks like symmetrical ripples in a pond and sounds quite natural, particularly when the cone is damped with the right snake-oil.

 

[leonard smalls]

Originally posted by 7_V
The main reason that I use 8" drivers is because they require a smaller box

Aahh, the vagaries of fashion
Wouldn't it be much easier to get decent low bass - i.e. <20Hz - just by using a bigger box and driver?
Like they used to do in't'olden days - and JBL and the like still do in their big monitors?
My speakers have a 12" plus 12" passive radiator - and they go low enough for my tastes... Though they were built in the days before interior design existed

 

[merlin]

I think there is a lot of myth in the belief that large drive units suffer in comparison with their smaller brethren. I suspect it stems back in time, before modern cone and voicecoil technology made larger drive units practical for hifi purposes

There is of course a compromise with both approaches, but modern 15" and even 18" drive units from companies such as ATC, Volt, Eton and JBL exhibit amazingly low distortion figures along with excellent linearity.

Four 10" per channel would really be a minimum for me I'm afraid

 

[titian]

I haven't heard the others but I heard the HTPS400 of JBL and I must say that maybe it has a very low distortion but it is very colorful.

Maybe good for movies and to shake your floor but nothing to do with clear / transparent reproduction of music.

 

[7_V]

Originally posted by leonard smalls
Aahh, the vagaries of fashion
Wouldn't it be much easier to get decent low bass - i.e. <20Hz - just by using a bigger box and driver?

Not really. As I said, I believe I can get better-defined bass and dramatically less cabinet vibration using smaller drivers.

Also, big boxes is not what Seventh Veil's about.

My speakers have a 12" plus 12" passive radiator - and they go low enough for my tastes... Though they were built in the days before interior design existed

You've effectively got a single 12" driver, ported design. These would have a 24dB/octave cut-off and I'd be surprised if you were getting much output <20Hz (room gain aside). How big is the cabinet?

Originally posted by merlin
Four 10" per channel would really be a minimum for me I'm afraid

Why not? It would be considerably more than you're using now.

 

[leonard smalls]

Originally posted by 7_V
You've effectively got a single 12" driver, ported design. These would have a 24dB/octave cut-off and I'd be surprised if you were getting much output <20Hz (room gain aside). How big is the cabinet?

About 110x40x40cm.
Celestion quote frequency range of 18Hz-40KHz - though it doesn't say whether that's -3dB or what..
But having heard speakers like the Lumley S2000 (and its 11 drivers :JPS: ) which are also quoted as 18Hz bottom end I'd believe it.
What I'm getting in-room is debatable but you can certainly feel it in your kidneys at even moderate (well quite moderate - so you can hear someone next to you...) volumes.
I've found modern slim-line speakers to beat or equal their top and mid-range, but nothing at sensible money to rival their bottom

 

[lowrider]

I am sorry, but 4 10" minimum sounds like a gross exageration for music, WM and many others are happy with 1 6,5"...

I got Michael's Eupens, my brother will be happy, even though it sounds the same...

 

[merlin]

Originally posted by titian
I haven't heard the others but I heard the HTPS400 of JBL and I must say that maybe it has a very low distortion but it is very colorful.

Maybe good for movies and to shake your floor but nothing to do with clear / transparent reproduction of music.

Titian,

that would be because it is part of the home cinema range (Home Theatre Powered Subwoofer 400). A twelve inch sealed enclosure, I agree that JBL HT kit sounds quite cinematic, although it is relatively low down the range.

JBl make many drive units, mostly in the pro arena, along with also designing and building bass units for the likes of Revel and Infinity. Ever heard the Revel Ultima sub? One of the world's finest IMO.

If you get the chance to hear the top drivers from the likes of JBL, ATC, T.A.D. etc, you will find that they are anything but coloured, indeed most top studio setups rely on them. I would accept however that JBL are associated more with Rock than classical.

Why not? It would be considerably more than you're using now.

Steve, what I was saying was that I might well enjoy the air moving capabiliites of four 10"s, but I have tried it before (the Tact subs). I like the simplicity of a pair of big boys moving effortlessly, but admit mine require a lot of real estate. Of course, it is possible to use an animal of a 15" in a small sealed enclosure, as is popular at the moment. Again, the compromise for me is the increased moving mass required in these designs along with power requirements and EQ.

So no correct solution as ever! However, I cannot see how you can get sufficient level at say 20hz out of a pair of unequalized 10"'s for them to have significant affect when listening to music at say 85db. Maybe you could help me out there.

 

[7_V]

Originally posted by leonard smalls
Celestion quote frequency range of 18Hz-40KHz - though it doesn't say whether that's -3dB or what.

Yes, pity. You could probably specify the Linn Kans the same way.

Originally posted by merlin
... However, I cannot see how you can get sufficient level at say 20hz out of a pair of unequalized 10"'s for them to have significant affect when listening to music at say 85db. Maybe you could help me out there.

Well naturally I'd be delighted to help, although I'll be building with 8"ers (10" much too vulgar for my tastes).

Seriously though, I'm working on a TL Little Awesome to compare with the 2 x 8" Little Awesome and then I'll move on to 2 x 8" with a TL and then 4 x 8", 4 x 8" TL and so on, until they drag me off and lock me up.

Actually, what are the measurements of your JBL cabinets? I'd be interested to know how many 8" drivers I could pack into the same size.

You'll have to come over to take a look when I get something meaty into prototype form. Of course, we won't bother to listen to music - just flash 0 - 50Hz measurement graphs at each other.

 

[merlin]

Originally posted by 7_V
Actually, what are the measurements of your JBL cabinets? I'd be interested to know how many 8" drivers I could pack into the same size.

Steve, the front baffle is 20" high and between 23" and 16" wide (trapezoid), so it is possible that you could fit 4 x 8" on it

Still, I like vulgar it kind of suits me.

The rest of my vital statistics are 24" deep with a rear firing 4" x 12" flared port to give a tuning of 27hz. Like you said - vulgar

Compromise is giving up some transient speed and impact for good old fashioned oomph. I would accept that 8x8" drive units might give a better transient response, but at what cost?

You'll have to come over to take a look when I get something meaty into prototype form. Of course, we won't bother to listen to music - just flash 0 - 50Hz measurement graphs at each other.

You'd win of course. You are a speaker designer. I am a half hearted DIY merchant. Still I'd love to have a listen at some point, and you must reciprocate (once I have found a way to tame a 50hz room mode )

 

[7_V]

Originally posted by merlin
Compromise is giving up some transient speed and impact for good old fashioned oomph. I would accept that 8x8" drive units might give a better transient response, but at what cost?

I don't know. I'll aim for oomph and we'll find out.

You'd win of course. You are a speaker designer. I am a half hearted DIY merchant.

You old flatterer. Don't give me that 'speaker designer' :bs: