Sealed Speakers better for systems with TTs....?

[CnoEvil]

The above question was sparked off by reading this quote by Keith Horward (HFN):

"When I was a nipper reflex speakers were a good deal less common than they are today, with the closed box alternative a lot more prevalent. Why? Because closed box loading better controls cone excursion at very low frequencies, obviating the cone flap that occurs when replaying warped or rippled vinyl, particularly if the arm-cartridge combination has a poorly placed and damped fundamental resonance.

By using up available cone excursion, and perhaps even pushing it beyond the driver’s linear range, this infrasonic diaphragm dance squanders output capability and increases distortion. If you’re an LP user, this is something to bear in mind when considering any reflex loaded speaker."

Most of the speakers that I used when I owned a TT (70s / 80s) happened to be sealed, but I wasn't aware of this as a possible advantage.....any thoughts / experience on this from you knowledgeable folk on here........?

 

[davedotco]

The above question was sparked off by reading this quote by Keith Horward (HFN):

"When I was a nipper reflex speakers were a good deal less common than they are today, with the closed box alternative a lot more prevalent. Why? Because closed box loading better controls cone excursion at very low frequencies, obviating the cone flap that occurs when replaying warped or rippled vinyl, particularly if the arm-cartridge combination has a poorly placed and damped fundamental resonance.

By using up available cone excursion, and perhaps even pushing it beyond the driver’s linear range, this infrasonic diaphragm dance squanders output capability and increases distortion. If you’re an LP user, this is something to bear in mind when considering any reflex loaded speaker."

Most of the speakers that I used when I owned a TT (70s / 80s) happened to be sealed, but I wasn't aware of this as a possible advantage.....any thoughts / experience on this from you knowledgeable folk on here........?

Cno,

The article is correct as far as it goes. The important point is that the loading on the bass cone varies with frequency, so if the port is tuned to be in phase at, say, 50-60hz, then it will be out of phase at a lower frequency so the air loading on the bass cone will be minimal.

If you look up details on porting a cabinet you will find the answers, the important thing to realise is that modern amplifiers have flat frequency responses down below 20hz and things like warp noise, rumble, footfall and even acoustic feedback can cause bass drivers to move a lot, even if this does not blow the bass drivers it is pretty bad news for fidelity.

Of course a well designed high pass (rumble) filter will solve the problem, some phono stages incorporate one into their eq curves but many do not. If I was putting together a vinyl system with ported speakers I would probably insist on steepish roll off below about 30-40 hz.

 

[MajorFubar]

This was the main purpose of the (long time obsolete) Rumble fliter, which was essentially a high-pass filter focussed at around 50Hz or so.

EDIT: Whoops, as already stated by DDC...

 

[CnoEvil]

Thx guys.

I have always been aware of the Rumble Filter, but hadn't taken on board the full benefit as regards "cone wobble".

:cheers:

 

[plastic penguin]

The tears are falling near the Lincs/Notts border.

 

[floyd droid]

That one has gone straight over my nut PP , care to expand a little

 

[plastic penguin]

That one has gone straight over my nut PP , care to expand a little

That's Steve's neck of the woods, and he has RS3 which, unless I'm mistaken are ported.

 

[floyd droid]

Ah , I see. Ta.

 

[chebby]

That one has gone straight over my nut PP , care to expand a little

That's Steve's neck of the woods, and he has RS3 which, unless I'm mistaken are ported.

Although the midrange drivers in the RS3 are in their own sealed compartments. (Same in my R3s I believe.) So they are part ported enclosure and part sealed enclosure.

 

[peterpiper]

first hifi speakers I ever heard in the seventies where sealed units, a pair of Wharfedale 'Super Linton' , made in yorkshire they were, They were not mine but my relatives, remember their sound very well, a very musical sound full of character

 

[plastic penguin]

That one has gone straight over my nut PP , care to expand a little

That's Steve's neck of the woods, and he has RS3 which, unless I'm mistaken are ported.

Although the midrange drivers in the RS3 are in their own sealed compartments. (Same in my R3s I believe.) So they are part ported enclosure and part sealed enclosure.

What's the technical advantage to that?

 

[stevebrock]

Kudos