Folded Horn Configurations?

[Pat C.]

I don't boost horn loading changing the world today lol.

There's some cool stuff going on in the pro audio world with horns right now. People like Danley Sound Labs with their synergy horn tops and tapped horn subs seem to be breaking through the line array craze. Heck, the Jericho horns are loaded with 15s or 18s and flat down to below 40 or 50hz. And they're using pretty small drivers in some models of subs, down to 8" in the Nano and TH28.

To circle back to the original post by @Ross W. Lovell, Tom Danley did a design some years back of a standard folded horn with 2x12" drivers dubbed the Invalid Link Removed as it was done with input from users on the Live Audio Board. But it was designed as a true pro audio sub with intended use below 100hz, not as a full range bass cab.

 

[agedhorse]

Most of Danley's low frequency designs are very much optimized for sub applications, or applications with some serious crossovers. Not so much for bass guitar where mid voicing and forgiving overdrive is important.

 

[Bill Whitehurst]

Byacey,
the 361 sounds a lot brighter than you would ever imagine.
I was shocked by how much mids they can put out.
I suppose if you wanted to move two big cabs
an 810 and a W horn together could make up for the weaknesses of each other.

 

[ranbunctious]

Greetings All,

Any reason nobody makes a folded horn in either a 2 x 10" or 2 x 12", or 4 x 10" or 4 x 12" configuration?

Just for clarification that either 1 on top and 1 on bottom, or 2 on top and 2 on bottom.

There must be a reason for it. Just amused how a standard 2 x10 or 2 x 12 work, never had a folded horn enclosure smaller than 2 x 15"?[/QUOTE
Same reason the tuba only has one mouthpiece. Same goes for just about any brass instrument. Would be interesting to see several guys trying to play a single tuba with several people blowing.

 

[ranbunctious]

Greetings All,

Any reason nobody makes a folded horn in either a 2 x 10" or 2 x 12", or 4 x 10" or 4 x 12" configuration?

Just for clarification that either 1 on top and 1 on bottom, or 2 on top and 2 on bottom.

There must be a reason for it. Just amused how a standard 2 x10 or 2 x 12 work, never had a folded horn enclosure smaller than 2 x 15"?

The cabinet I made has 2 18s. One is front mounted, and the other is downward mounted at the rear to the horn. It works out pretty well...

 

[ranbunctious]

The ultimate challenge with folded horn subs for bass guitar applications is the path length differences in the low mids and mids, along with multiple throat reflections. If you were to look at the broad band impulse response, or look at signal coherency, you would see that the signal is made up of a bunch of smaller signals all slightly time offset from each other, along with increased distortion components (in the midrange).

Combine this with the necessary size for low frequency extension, and the weight, and the added cost for materials, packaging and shipping and you can see why they quickly fell out of favor as amp power got bigger.

If it were such a great solution, one of the hundreds of commercial bass speaker manufacturers would offer this kind of cabinet, but they don't (as far as I am aware of).

I've been playing a folded horn cab on bass guitar for 30 years. My amp has a extensive EQ, so I can get just about any sound or boost I need. Have to admit though, I play an additional amp with 3 15s that really compliment each other. In the 70s & 80s, most bassplayers in large concerts all played Ampeg SVT amps thru Cerwin Vega folded horns. Sweetest sound in the word...

 

[agedhorse]

I've been playing a folded horn cab on bass guitar for 30 years. My amp has a extensive EQ, so I can get just about any sound or boost I need. Have to admit though, I play an additional amp with 3 15s that really compliment each other. In the 70s & 80s, most bassplayers in large concerts all played Ampeg SVT amps thru Cerwin Vega folded horns. Sweetest sound in the word...
View attachment 3937595

Except that neither of those cabinets you picture are folded horns!!!

I wouldn't say that most bass players playing large concerts played SVT amps through CV folded horns... in fact I would say that represents a minority and a significant minority at that. When folded horns were used, it was generally because of the need to be heard with limited amp power rather than for tonal reasons.

Once bass reflex cabinet design got better, and drivers got (much) better, and amps were capable of greater power, the concept of folded horns faded away with some fairly specialized applications in the pro audio world. That's why you don't see manufacturers of new bass cabinets including folded horn cabinets in their product line. Tonal preferences have changed, evolved. So has the willingness (and in many cases, the ability) to move large, heavy cabinets with limited low frequency extension (unless multiples are used to increase the horn mouth area are used).

I'm quite familiar with the technology, having worked for the original Cerwin Vega company (field service and support of cinema and installation products, including folded horn cabinets) in the early 1980's.

 

[JacklegBass]

In the 70s & 80s, most bassplayers in large concerts all played Ampeg SVT amps thru Cerwin Vega folded horns.

I only recall seeing two shows with C-V folded horns... I saw Uriah Heep in 1975 after John Wetton had taken over bass chores.... He ran a pair of Ampeg SVTs into a pair of Cerwin-Vega B48MF cabinets which had an 18" driver into a folded and a front loaded 12". His sound was pure mud.

The other show would have probably been 1973-74 -- Ian Lloyd and Stories ("Brother Louie") with Kenny Aaronson on bass. He also had a pair of B48MF cabinets that he drove with a Furman PQ3 parametric EQ pre-amp into an unknown power amplifier (I suspect BGW 750). He sounded great.

 

[byacey]

Byacey,
the 361 sounds a lot brighter than you would ever imagine.
I was shocked by how much mids they can put out.
I suppose if you wanted to move two big cabs
an 810 and a W horn together could make up for the weaknesses of each other.

I've never personally seen one, but from the few drawings I found on the net, they aren't really a properly engineered horn, more so a direct radiator stuck behind a couple of deflector baffles. More than likely, these were an empirical design based on what someone thought looked good.

A well tuned horn filters out most of everything above the horn upper cut-off frequency, including upper harmonic distortion.

 

[agedhorse]

The B48MF was a very deep cabinet. The direct radiation mid driver was used to get around the upper range limitations of a folded horn. This was very much a specialty hybrid speaker and worked quite well. Iirc it weighed around 200 lbs though.

 

[Wasnex]

I've never personally seen one, but from the few drawings I found on the net, they aren't really a properly engineered horn, more so a direct radiator stuck behind a couple of deflector baffles. More than likely, these were an empirical design based on what someone thought looked good.

A well tuned horn filters out most of everything above the horn upper cut-off frequency, including upper harmonic distortion.

Probably just a W horn with a rather high cutoff. We recently had a thread on the V4 W horn, and posted spec sheets. Looks like those start cutting off at 80hz .

Here is the thread if your interested: New Cab Day, 70's Ampeg V4-B, Boom!

 

[agedhorse]

Here's an example of the challenges with folded horn topologies, this is the B-36 (more common than the B-48 due to the size/weight), you can see that there is a large mid bass hump (which is about 50Hz lower on the B48) and even if these measurements aren't perfect (this came off of the web, the SHAPE of the curve is accurate as I remember the measurements I did) and how it falls quickly at the low end. It's quite efficient at the mid hump however, this is the tradeoff.

Above the mid-bass hump, around 350Hz, the response also falls like a rock and all the peaks and valleys are due to internal reflections within the throat of the horn. All folded horns share this shape, though the longer the horn throat combined with a larger mouth extend the low frequency... at the expense of even worse mid response.

Now one way to get MUCH better low frequency performance is to combine the folded horns so that the mouths couple. Doubling the mouth area for a given throat length increases the LF sensitivity and increases the effective LF extension. For pro audio applications, these cabinets are typically crossed over around 100 - 200Hz, so the mid response doesn't matter. Also, if you were to measure the distortion of the folded horn, it would be quite low where the horn is effective and rises very high as the throat reflections come into play.

Adding a mid driver with a crossover, and rolling off the mid response of the folded horn with a proper crossover is a much better sounding solution, is much more articulate. That's the reason for the added mid driver in folded horn cabinets like the B48MF.

I just looked at my CV docs, the B36A has a published response of 35Hz - 400Hz (-10dB) and the B48 has a published response of 35Hz - 350Hz (-10dB) and I recall this being with a minimum of 2 cabinets coupled. The shorter the horn, the better the mid extension. This is one reason that some of the shallow, short horns worked "ok" for bass, the trade-off of LF extension for MF extension worked.

There was also a L-48SE cabinet, published specs of 18Hz - 200Hz (-10dB), this was the full sized Sensurround cabinet and it's huge. 2' wide, 4' high x 4' deep and weighed well over 200 lbs, this is what we used (a module of 4) when demonstrating the earthquake effect from the movie on the technology tours we did for the company. They were crossed over around 100hz and in a module of 4 they were pretty darn flat to 20-25Hz. The sound track was on a 15 IPS half track real to reel and it really was an experience. I wish I had pictures.

 

[shadven]

The best sounding speaker cabinet I have ever played through (and I happen to own one) is the Ampeg V4B 2x15 folded horn. Very loud with powerful mids / low-mids, warm and punchy as hell. It is very loud, very heavy, very large. But, to me it has the perfect bass tone ever. If it just wasn’t such a beast to move around.

 

[bobyoung53]

The best sounding speaker cabinet I have ever played through (and I happen to own one) is the Ampeg V4B 2x15 folded horn. Very loud with powerful mids / low-mids, warm and punchy as hell. It is very loud, very heavy, very large. But, to me it has the perfect bass tone ever. If it just wasn’t such a beast to move around.

I bought one of those last year and haven't been able to get back to the U.S. to pick it up yet, but I'm finally heading back in April. The seller told me he'd hold it for me, I remember them sounding really good too. I don't know if I'll ever be able to use it considering the rooms I'm playing in now (or was) and the lack of gigs, but I've always wanted one.

 

[Old Fart]

FWIW, this was my first big rig, WAY WAY back in the before time. Sunn 215 SH. It was cool looking but had significant drawbacks. Its tone on stage was more middy and high-mid, and stage volume was low compared to FOH. FOH HATED it because the sound developed in the back of the room more than the front and it was deep-sounding there. So....I turned it up to hear myself, and they kept asking me to turn down.

 

[shadven]

I bought one of those last year and haven't been able to get back to the U.S. to pick it up yet, but I'm finally heading back in April. The seller told me he'd hold it for me, I remember them sounding really good too. I don't know if I'll ever be able to use it considering the rooms I'm playing in now (or was) and the lack of gigs, but I've always wanted one.

I bought one of those last year and haven't been able to get back to the U.S. to pick it up yet, but I'm finally heading back in April. The seller told me he'd hold it for me, I remember them sounding really good too. I don't know if I'll ever be able to use it considering the rooms I'm playing in now (or was) and the lack of gigs, but I've always wanted one.

I bought mine just because I wanted it. I haven't been able to do an actually did with it yet. It is a pretty imposing cabinet. Looking at it straight on it looks like a an Ampeg 810, but it actually is quite a bit deeper and much heavier. Most of my gigs have been in smaller rooms. I would be a jerk if I showed up with my V4B, but I am hoping for that big out door gig one of these days!

 

[daveman50]

FWIW, this was my first big rig, WAY WAY back in the before time. Sunn 215 SH. It was cool looking but had significant drawbacks. ...

View attachment 4182842

I bought a Sunn Concert Bass rig in '73. I looked at the 215SH cabinet and thought, What the ****? Where's the speakers? I A/B'd it in the store with the conventional 215S and went with that instead (which I still have). I couldn't hear myself with the SH. But I suppose in a perfect world I'd have 'em all and stack 'em up! Like Entwistle.

 

[1n3]

I've had a casual interest in horns ever since hearing Paul Klipsch speak years ago. The cool-sounding parts were, "increased efficiency" and "reduced doppler distortion". 30+ years later, increased efficiency matters less than it used to, and it turns out that many bass players *like* doppler distortion.

Most of these folded-horn bass cabs are more mid-bass horns. You get about three octaves of horn-loading, with rising response from 1/4 wave to 1/2 wave, then a ragged and falling response above that. Sounds kinda bad, but it might just be your thing. I gigged with some years ago. They weren't tonal nirvana for me, but had a usable and sometimes cool sound.

With cheap lightweight power and better drivers, there will be fewer fans of folded horn cabs, but they've got a unique character that will appeal to some.

 

[ricardol]

I've had a casual interest in horns ever since hearing Paul Klipsch speak years ago. The cool-sounding parts were, "increased efficiency" and "reduced doppler distortion". 30+ years later, increased efficiency matters less than it used to, and it turns out that many bass players *like* doppler distortion.

Most of these folded-horn bass cabs are more mid-bass horns. You get about three octaves of horn-loading, with rising response from 1/4 wave to 1/2 wave, then a ragged and falling response above that. Sounds kinda bad, but it might just be your thing. I gigged with some years ago. They weren't tonal nirvana for me, but had a usable and sometimes cool sound.

With cheap lightweight power and better drivers, there will be fewer fans of folded horn cabs, but they've got a unique character that will appeal to some.

Maybe the new bass modeling amps can mimic these folded horn cabs accurately...

 

[Roxbororob]

Here's an example of the challenges with folded horn topologies, this is the B-36 (more common than the B-48 due to the size/weight), you can see that there is a large mid bass hump (which is about 50Hz lower on the B48) and even if these measurements aren't perfect (this came off of the web, the SHAPE of the curve is accurate as I remember the measurements I did) and how it falls quickly at the low end. It's quite efficient at the mid hump however, this is the tradeoff.
View attachment 3937780

Above the mid-bass hump, around 350Hz, the response also falls like a rock and all the peaks and valleys are due to internal reflections within the throat of the horn. All folded horns share this shape, though the longer the horn throat combined with a larger mouth extend the low frequency... at the expense of even worse mid response.

Now one way to get MUCH better low frequency performance is to combine the folded horns so that the mouths couple. Doubling the mouth area for a given throat length increases the LF sensitivity and increases the effective LF extension. For pro audio applications, these cabinets are typically crossed over around 100 - 200Hz, so the mid response doesn't matter. Also, if you were to measure the distortion of the folded horn, it would be quite low where the horn is effective and rises very high as the throat reflections come into play.

Adding a mid driver with a crossover, and rolling off the mid response of the folded horn with a proper crossover is a much better sounding solution, is much more articulate. That's the reason for the added mid driver in folded horn cabinets like the B48MF.

Below is my take on a B36MF.
I started out with a 6" sealed back midbass but revised up to the 10" sealed back midbass. The 10" is crossed to come in at about 700hz and I let the 18 just run itseld out of steam. Sounds great (sujectively) but is for special occasions only due to the load in/out. In the second photo you can see that I used my new 100watt tube amp, it was wonderfull.

I dont own a fridge but have front loaded cabs also that are better suited to most situations. Im build some jacklites 10s (because I love the sawdust) but am really looking forward to Duke taking new orders!