New Advent Cabinet Construction.

[Guest One-Shot Scot]

The New Advent Loudspeaker came in four separate models: The A3, U3, A4 and U4. The A-series New Advents were Furniture models and the U-series Advents were Utility models. I currently have some of the A3, A4 and U4 models, but none of the U3 models.

Here is what is stated on the back cover of the brochure entitled, _The New Advent Loudspeaker_:

*** *** ***

Cabinet Construction

The cabinet of the New Advent Loudspeaker is constructed of non-resonant particle board finished in genuine walnut veneer with a solid walnut front molding.

The New Advent Loudspeaker is also available in a "Utility" cabinet on non-resonant particle board finished in walnut-grain vinyl.

*** *** ***

For a modest additional cost, the New Advent Loudspeaker buyer could choose to have a Furniture cabinet decorated with genuine walnut trim instead of a vinyl-clad Utility cabinet. Until recently, I assumed that outer cosmetics were the only differences between the Utility cabinets and the Furniture cabinets. I also assumed that the sonic characteristics of the Utility cabinet were identical to those of the Furniture cabinets. I was wrong.

The overall construction of the A3 and A4 Furniture cabinets is not identical in the models that I have:

The A3 cabinets have medium-grain particle board only on the front and back panels of the cabinet. Another type of real wood paneling -- possibly plywood -- was used for the top, bottom and side panels.

The A4 cabinets are made entirely of fine-grain particleboard.

The huge difference in cabinet construction is evident in the U4 models, which are made entirely of coarse-grain particleboard. The U4 cabinets also have two vertical baffles mounted on the center of the left and right cabinet walls, which measure 21" x 2" x 3/4". The A4 and A3 cabinets do not have these baffles.

As an experiment, I lined up pairs of A3, A4 and U4 cabinets, all of which have had their grilles, crossovers, insulation, tweeters and woofers removed. Tapping on the tops of A3 and A4 cabinets produced similar sounds and they exhibited virtually no echo. However, tapping on the tops of the U4 cabinets produced a very noticeable hollow, ringing echo, which lasted for about half a second. In spite of Advent's claim to the contrary, the U4 is not made of "non-resonant" particle board.

After hearing the unpleasant sonic characteristics of the U4 cabinets, I am inclined to believe that the vertical baffles were installed in an attempt to minimize the echo. I am assuming that the U3 cabinet is the same as the U4, but since I don't have one, I can't know for sure.

Now, I am beginning to appreciate the value of the various sound-deadening materials offered in the Parts Express catalog. I am very interested in hearing from anyone who has dealt with speaker cabinet resonance, particularly in the U4 cabinet.

The website below contains pictures of the interiors of the A3, A4 and U4 cabinets:

http://home.comcast.net/~newadvent/NewAdventCabinets.html

One-Shot Scot

[Doug G.]

Thanks for the write-up, Scot. Very interesting. Excellent photos!

Almost makes me want to take the woofers out of my original Advents to see differences between the Walnuts and Utilities but with that Mortite sealer, I'm too lazy to do it :^)

Doug

[Guest One-Shot Scot]

>Thanks for the write-up, Scot. Very interesting. Excellent

>photos!

>

>Almost makes me want to take the woofers out of my original

>Advents to see differences between the Walnuts and Utilities

>but with that Mortite sealer, I'm too lazy to do it :^)

>

>Doug

Doug:

I'm glad that you found my post interesting. However, I have some more information in regard to this part of my original post:

<>

<>

<>

After posting this information, I moved the pairs of A3, A4 and U4 cabinets away from the wall and performed some more of my primitive resonance tests. As it turns out, tapping on the tops of the cabinets does not fully demonstrate the acoustic reverberation characteristics of the speakers. When tapped on the top, sides or back panels, each of the six speaker cabinets responded differently in both intensity of resonance and in pitch.

Slapping the back panel of the speakers produces a lot more noise and resonance when compared to slapping the sides. Surprisingly, the U4 cabinets sounded similar to the A4 cabinets when slapped on the side and back panels, but the A4 cabinets were a little quieter. The thing the really surprised me is that the pair of A3 cabinets made the loudest and longest-lasting ringing sounds of all the cabinets after slapping the backs and sides.

As a result of my resonance tests on the New Advent cabinets, I have reached a tentative conclusion as to which dampening material to use. I think that it is best to use whatever dampening material absorbs cabinet panel vibrations and makes the speaker cabinet stop resonating. These materials can include Dacron foam, acoustic dampening foam, fiberglass, Acousta Stuf, asphalt and vinyl dampening sheets etc.

Stuffing four of the original Advent foam squares into an A3 cabinet went a long way toward muffling the resonance, but the hollow noise remained. I think that my next experiment will be to line the inside cabinet walls with vinyl acoustic dampening sheets.

One-Shot Scot