T.M. or M.T.?

[merlin]

A question for some of you clever guys if I may.

Here is a typical JBL 2 way - my old 4338 before the move.



Like so many before it, we have the horn sitting at ear height and the bass driver below - some 18 inches from the floor.

Could one of the resident genius's explain why we don't see the horn at ear height and the 15" bass cone ABOVE it with a sturdy stand to support them?

OK so not quite so pretty (?) but wouldn't this help reduce floor reflections and mute the floor ceiling room mode quite effeectively?

Is there some obvious reason sonically why JBL or anyone else would do it this way?

[Ian Mackenzie]

Merlin,

I think you answered your own question.

In the home decor is everything. In the studio the horn is often inverted.
Room modes and reflections are a complex mish mash. You need to calculate and measure what is happening in your listening postion

For grins try inverting it on a raised stand.

I'll bet you dont like the sound just based on appearances. It may even sound thin due to lack on room gain below 100 hz. Typically smaller systems like this have baffle compensation so I would follow the manufacturers recomendations on positioning.

[clubman]

I like the iPod siting up there...and yes these days room decor is everything.

[merlin]

Ian,

no I wasn't thinking of inverting the 4338. I was thinking of building my cabs for the project speakers inverted- logically it makes more sense given that the optimum position for most people with a c.8ft ceiling (on the vertical axis) is going to be taken by the midrange horn.

I agree that most room acoustics are a royal pain but the floor to ceiling mode is really easy to work out, as is the best place to position the bass driver. In the picture, the 1500FE is centred at 1/4 of the room height - less than ideal and causing the inevitable suck out due to the second harmonic of the vertical node.

I shall experiment and let you know how I get on

PS. Obviously I couldn't invert the 4338 as the iPod would fall out if it's dock.

[Zilch]

Easy enough to try:

Sub on the bottom, the rest is "In yer FACE!"

Many designs rely on floor boundary reinforcement for bass enhancement, I would assume.

On another site, it was postulated that bass was heavier, thus necessitating woofer location on the bottom, so that it wouldn't interfere with the mids and highs.

They'd fall at the same rate, wouldn't they?

[hjames]

Merlin - how about a better view of your speaker stands. One thing I noticed in the shots from many of the Asian Audiophile sites is that there is a different aesthetic to the speaker stands in their homes. Not always a polished lacquer - but definately different than what we think of in the west.

[Ian Mackenzie]

More railway Tracks?

Acoustic clouds tend to be the prefered aproach to dealing with ceiling issues.

I tink we need to see a concept drawing of your Tad-manicus!

[glen]

Many recording studios do as you suggest, mounting the large cabinets into the wall with the horns on bottom and the woofers above.

I believe there was an article on the web where famed studio designer John Storyk claimed to have been the first to do this in a recording studio when he installed some big Westlake monitors in the control room of Albert Grossman's Bearsville Studios in upstate NY. He said he did it to keep the high frequency driver's sound from reflecting off of the surface of the recording console.

The old Westlakes had a hornless high frequency compression driver mounted just under the large, protruding wooden midrange horn. Turning the Westlakes upside down put the high frequency driver above the wooden horn which blocked the sound that otherwise would have bounced off the console.