Amps/Speakers-Open or Closed Back?

Alan Watt · From: Graton, CA, USA

As I'm generally new to PSG, and only been consistently playing steel guitar for about 3 years, I'm in the process of dialing in my tone and tweaking my electronics/amp rig to get there.
I've noticed a lot of the top line PSG amps, such as Weber or Quilter, are closed back, though some Webers I've seen are open back. I know that Tom Brumley played thru a Fender Bassman with 2 12" speakers; closed back. On the other hand, I know guys who have and still use a Twin Reverb-open back.
So I'm curious on opinions on this. I'm guessing that the closed back speaker cabinets offer more "punch", but ...?
Right now I'm using a Mesa Boogie Mark II with an FX rack; nice sound but I think I could do better, down the line. Not sure about a tube front end to handle the dynamic nature of a PSG pickup, but like the warmth of those 4 6L6s.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

I'm not an audio engineer, but I'll give you my take on the subject. Each has it's advantages and disadvantages; there are a whole lot of different qualities in the two designs. To start, closed backs are more efficient. (They can sound twice as loud with the same amount of power.) They're heavier and usually larger, and have more bass, more "punch", as you described it, projecting farther, but over a narrower area. Their highs are not quite as good, due to the dampending effect of the constricted air on the speaker cone's movements. But that can also protect the speakers, somewhat, when higher levels of power are used.

Open backs are a different bag altogether. They're cheaper and easier to make, and they can be made smaller (read: shallower, and lighter). They also sound more open and "airy", with very crisp and clear highs, but with less punch and bass. Their dispersion is better, too, as a lot of the sound goes out the back of the cabinet. But as a result, they're not as efficient, requiring more power for the same amount of loudness (audio watts perceived). And since they offer little or no dampening to the cone's movements, they will require huskier speakers when high levels of power are called for.

Jack Stoner · From: Kansas City, MO

I've been playing for probably too long (I started in bands in 1959), I've always used open or partially open back speakers.

My amp, now, is a Quilter Travis Toy 12" speaker model. It uses a Quilter Tone Block 202 amp (which can sound very "Fenderish") and a Quilter Toneblock 12HD speaker enclosure. The original Toneblock 12HD enclosure had a wooden mounting on the rear to mount the TB202 amp and with the wooden mounting it turned the enclosure into a partial open back and even a pseudo ported enclosure with the relatively small rear opening. Perfect fit for the Travis Toy 12 speaker as it had very good, but not piercing, highs and good lows - even for the C6th low strings. The new TT12 amp speaker enclosure was damaged in transit and Quilter replaced the entire amp with a new one. The new one didn't sound the same and the reason turned out to be the "new version" Blockdock 12HD speaker cabinet. The new version had the wooden mounting mostly cut out to accept physically deeper speakers and that changed the speaker cabinet response. With the TT12 speaker the highs were more pronounced and some of the lows were gone as the cabinet turned into a more open back cabinet. Quilter replaced the cabinet with the old model and made me happy.

On another note, the speaker makes a difference too. Another experience. I bought a used Nashville 112 amp with a Telonics TSNEO-12 speaker (made by Eminence as is the Travis Toy 12). I had a Travis Toy 12 speaker so I removed the Telonics and installed the TT12 speaker. In my comparisons, the Telonics won in the NV112 enclosure - it had smoother highs and a tad bit more lows. Back to the Quilter Blockdock 12HD cabinet in my Travis Toy 12 amp. I removed the Travis Toy speaker and installed the Telonics. In this enclosure the Travis Toy 12 speaker was the winner with a little cleaner highs and more lows.

Dave Hopping · From: Aurora, Colorado

If you gig and have to move gear around, portability becomes an issue. I have a Twin-Reverb Custom 15 and a Session 500 that sound nice as you please, but my Milkman Half & Half is the one that leaves the house.

I can't imagine acquiring something like a Dual Showman for anything other than music-room bragging rights. Winking

Alan Watt · From: Graton, CA, USA

Thanks, everybody. Gave me a lot of info.
And yeah, while a Dual Showman strikes me as an ideal PSG amp, I'm way past carting that kind of stuff around. The Boogie is heavy enough!

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

Tom Brumley played various amps, including a tweed Fender Bassman (recovered in black tolex) with a single 15" speaker (I think JBL) - open back. And there are plenty of videos with him playing a Twin Reverb.

Both open-back and closed-back can sound good. A tweaking of the EQ can make either work. Overall, I usually prefer the open-back sound - my favorite clean pedal steel sound remains a Twin Reverb (or its head-only brother the Dual Showman Reverb). But I'm running my little (4 pounds) Quilter Tone Block 201 with a closed-back cab with a single 12" speaker in it. I use an Eminence Red Coat closed-back when I want to play both steel and guitar - it works surprisingly well for clean pedal steel, but was picked for the slightly warmer sound for guitar. But I also have a semi-open-back cab with a Telonics neo 12" speaker for just steel. Since the Telonics is rated around 300 Watts, it gives more clean headroom when I want to be louder for pedal steel.

Erv Niehaus · From: Litchfield, MN, USA

I always considered an open back amp a guitar amp and a closed back amp a bass amp. Very Happy

Erv

Peter Harris · From: South Australia, Australia

Karl Paulsen · From: Chicago

Another newbie question on this topic.
Is it true that when it comes to combo amps, closed back cabinets are only used with solid state amps?

This would make sense to me considering the pounding that tubes would take in a closed cabinet, not to mention the cooling issues.

Is it safe to say also that steel combo amps with closed backs are very much the minority?
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Donny Hinson · From: Glen Burnie, Md. U.S.A.

Yes, cooling is essential, so most combo tube amps do it like the one below. But you're right, they are kinda rare.

Doug Hall · From: Alabama, USA

Closing up an open cabinet will Lower the cabinet's resonant frequency, generally speaking, and is evidenced in the design of *most bass speaker enclosures. A fully enclosed speaker (aka, "infinite baffle") will sound boomier/bassier than an open-back cabinet of the same size.
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Dale Rottacker · From: Walla Walla Washington, USA

Carey Hofer · From: South Dakota, USA

For my lapsteel, archtop and acoustic I use a Raezers Edge Luna 700 with a New York 8 (single 8" speaker). It's a closed back with two small round ports in front. I switched to that from an open back with a 12" Eminence Wheelhouse 150. My sound is now more focused, especially in the low end and overall more balanced throughout the spectrum. There is also one of the Raezers Edge adjustable tweeters installed which I use mainly for my acoustic set up. Happier with this than the 12" wheelhouse 150 set up. Only drawback for me is that it is not quite as loud, but with a 700 watt amp who cares? Laughing

John Larson · From: Pennsyltucky, USA

I've always associated tight and punchy with closed back and open and loose with open backed. Probably comes from being a metal guitarist where closed back is the norm for a tight rhythm guitar sound.
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