Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Cabinets-Speakers => Topic started by: punkykatt on March 03, 2015, 08:36:58 pm

Title: Speaker baffle with cross in speaker cut out
Post by: punkykatt on March 03, 2015, 08:36:58 pm

Hey Guys,  what is the purpose of the cross in the speaker baffle speaker cutouts on this mid 60`s Harmony amp?  Does it act like a beam blocker or is it there for support? Just wondering.

Title: Re: Speaker baffle with cross in speaker cut out
Post by: sluckey on March 03, 2015, 09:20:30 pm

Harmony was a budget product. Very budget! I'm betting the cross is for strength. That baffle could be made of 1/4" Masonite.

Title: Re: Speaker baffle with cross in speaker cut out
Post by: Willabe on March 03, 2015, 10:46:01 pm

I agree with Sluckey, it's a cross brace.

But there where a number of old amps, that for what ever reason, strength issues or looks (a few 50's Gibson's comes to mind), did have some type of speaker baffle cut out that did partially block the speakers sound.

Happy accident's?


                         Brad     :icon_biggrin:
   

Title: Re: Speaker baffle with cross in speaker cut out
Post by: supro66 on March 04, 2015, 11:22:10 am

My guess it was to protect the speaker from bear bottles  :l2:
I have a Supro 6420 Thunderbolt [ 1960's ] it has a cross in the speaker hole

Title: Re: Speaker baffle with cross in speaker cut out
Post by: Willabe on March 04, 2015, 11:23:25 am

 :laugh:

Title: Re: Speaker baffle with cross in speaker cut out
Post by: supro66 on March 04, 2015, 11:42:19 am

As you can see the old Supro and the new one I built

Title: Re: Speaker baffle with cross in speaker cut out
Post by: punkykatt on March 04, 2015, 02:02:56 pm

Quote from: supro66 on March 04, 2015, 11:22:10 am

My guess it was to protect the speaker from bear bottles  :l2:

I thought the Chicken Wire in front of the stage did that. LOL.    Thanks for the reply`s Guys`s

Punky

Title: Re: Speaker baffle with cross in speaker cut out
Post by: supro66 on March 05, 2015, 08:14:14 am

Sometimes practice in the garage can be very combatant  :BangHead:

Title: Re: Speaker baffle with cross in speaker cut out
Post by: Jim Coash on April 06, 2015, 07:44:50 pm

My Ampeg B-15S had a crossbar from left to right over the speaker cut out.  When I built a new baffle to fit an E/V-15G I made it the same way.  Both new and original baffles were 3/4" but I am sure that was there for additional strength.  None of those would have any impact on the sound of the cabinet.  Bass is omni-directional, for the most part.  When the wavelength reproduced becomes shorter than the cone diameter the output will measure the same no matter where you are measuring it from, including from behind the box.  Only high and mid frequencies would be affected by having a hard surface blocking them, especially the highs.  The best audio speakers always mount the tweeter right on the front of the baffle to avoid diffraction.  My KEF Reference One speakers use a woofer that is entirely inside the cabinet.  Bass frequencies exit through the front mounted port.  A home audio sub-woofer doesn't care which way the speaker cone faces at all; it sounds the same regardless.   That is also why the PA at live shows leave the bass bins anywhere they will fit but the hi/mid cabinets are carefully positioned, usually flown over the stage, so that they cover the listeners properly.  Guitar amps do not need to be concerned with those factors.  An open back Fender amp sounds nearly the same even when it is aimed directly away from the audience.  Jim