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Tone-Ring vs. Traditional Porting vs. Sealed

Posted: 12 Apr 2004 11:38 am
by Tyler Macy
I am going to have a repro fender showman 1X15" cabinet built for a D130F I have sitting around. I originally planned on a tone-ring design, but now I am wondering if a traditional front port or sealed enclosure would be better.

This will be for steel and tele, btw.

Posted: 15 Apr 2004 5:30 am
by Brian Davis
had to bump this up as I am quite curious to hear the experts sound-off as well...


Posted: 15 Apr 2004 9:17 am
by David Doggett
I'm no expert, but I've been looking into this myself lately and have some thoughts. I don't know anything about tone-rings and would be interested in what the point of them is. There have been some threads on the open vs. closed back issue. What I make of the history of this is that the original guitar amps in the '40s-'50s were all open back. Actually they were mostly designed to be set out in front of the player, like PA speakers, with the knobs top rear, facing backward. That speaker placement helped minimize feedback from instruments (many of which were feedback prone acoustic instruments with pickups added), and the open back acted as a monitor. Also, there were few or no PAs, and vocal mics were commonly run through the instrument amps (another reason to put them out front). That was part of the original impetus for dual channel amps.

As amp wattages increased and there was more use of electric bass, it was found that separate closed-back cabinets were kinder to speakers. And, with porting and reflex designs borrowed from hifi applications, these became more efficient.

We're no longer bound by all that history, and can do it either way. It is still possible to set an open-back speaker out front, and use the sound coming out the back as a monitor, but almost nobody does that today. An open back cabinet set at the back of the stage sounds different depending on what is behind it. A good reflective wall close behind it can help spread the sound over the room. A curtain or a lot of space behind it can deaden the sound.

Closed back cabinets have a consistency of sound not as strongly affected by the location. They also help protect against blowing a speaker with low notes. And with a little porting or reflex slotting, they give a boost to the bass range. This is more important for bass guitars, and it's not clear to me that even C6 or B6 get down in the low bass range where this really matters much, especially in the small cabinets steelers prefer.

A good size cabinet with a Thiele slot or reflex design does seem to be very efficient for steel, especially in the low range. This is also the principle of the Enhancer stand for open back amps. Like a reflex cabinet, it kicks all the sound out the front of the cabinet and increases volume.

An interesting thing I have done recently is to take the chassis out of a heavey combo amp and put it in a separate head (cheap homeade crate, or from Mojo for about $200). Then you put a closed back on the old combo cabinet, and the front slot where the faceplate was turns this into a Thiele reflex cabinet. You could also seal the faceplate slot and leave the cabinet open back. You end up with a couple of 30-40 pound packages that are easy to carry one in each hand - much easier for me to handle than a single 60-90 lb combo. In addition, you can keep the amp head beside your steel for easy tweaking, and put the speaker at the back of the stage (preferably on a chair or stand). I find this makes it easier to mix my sound with the rest of the group.

At the moment I have a couple of 15" speakers, one in a homemade Thiele reflex cab and one in an old combo cab, as described above. I will soon be getting a small closed-back cabinet, probably from Marrs. If these sound good, I may switch to them, because they are smaller and lighter.

Posted: 16 Apr 2004 11:39 am
by Dave Van Allen
<SMALL>I don't know anything about tone-rings and would be interested in what the point of them is. </SMALL>
From a "period" Fender advertisement for a Tone Ring Cabinet:
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It's basically a port that "encircles" the speaker - reflected bass exits around the source of the forward speaker projection...
the above diagram is worth several hundred words<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Dave Van Allen on 16 April 2004 at 12:39 PM.]</p></FONT><FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Dave Van Allen on 16 April 2004 at 12:42 PM.]</p></FONT>

Posted: 16 Apr 2004 12:56 pm
by Brian Davis
Sweet diagram. Thanks for the background, guys.

Posted: 20 Apr 2004 11:19 am
by David Doggett
Well now, that's mighty cool. Where can I get one of these?<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by David Doggett on 20 April 2004 at 12:19 PM.]</p></FONT>

Posted: 20 Apr 2004 12:41 pm
by basilh
Would this be one of those 'Tone-Ring' Dual Showman cabs ?
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10171&item=3719119767

Baz


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<SMALL>Steel players do it without fretting</SMALL>
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