Any good plans out for FLH's?

[chrapladm]

I cant help but wonder what plans are out there that are for FLH's.

I have designed a few but nothing to post and know others can do better. I saw a post with Ivan stating that he could not tell the difference between the TH812, TH18 and BC412. This all of coarse level matched and playing with in their intended BW.

I have always liked FLH. And unfortunately for me hve never had a chance to have a PA FLH to compare to a TH in a A/B.

So I am curious if others out their have any designs that they could share or help me get something to my liking.

I know a TH18 can best a dual 18 ported cabinet. I will be building a Othorn soon with a 21SW152. That will be my staple to compare against. I was going to build one anyways for another project.

So my goals are to build something like a BC218 with -3db 26hz and -10db 22hz.

I am not trying to do a complete copy. I just would like to build a extremely capable 18" FLH. I think it would be nice if it was a dual driver FLH but single is fine also.

I would also prefer to use 18 Sound speakers or BC. BC seem to work the best for budget. SW115, TBW and so on.

Anyways thanks for anyone's ideas or thoughts. Zwiller...

 

[Osse]

+1, and I also saw Ivan write that he never saw a paper or test backing up the 'fact' that FLH's extend extension when used in multiples, however this is public opinion which most people seem to agree on.

 

[just a guy]

I believe what he said was that he didn't see it extend more than 2 or 3 hz. This is exactly what happens in sims and what you see in measurements of flhs.

A lot of people think stacking a bunch of flhs is going to extend the low end by an octave or something crazy like that. This is never going to happen.

 

[xrk971]

This is one of the better documented ones by Inslowsound.

Folded bass horn - The Paper Horn by Inlow Sound

t

 

[tb46]

Hi chrapladm,

Post #1: "...I know a TH18 can best a dual 18 ported cabinet..."

Are you saying that w/ a great deal of certainty?

Here are three simulations w/ the B&C 18TBX100, a carefully designed TH, and very quickly thrown together BR and STTL (tapped horn, bass-reflex and short-tapered transmission line). The TH is a single driver @ Eg=2.83, and the others are dual driver parallel @ Eg=2. Similar volumes (the TH is the largest) and Spl curve levels. The non-TH have lower displacement (for the same SPL), so I would assume, that they will have higher output SPL @ Xmax, they also seem to have better impulse response and group delay. So, what am I missing in the simulations?

It would be quite interesting to hear all three in the same environment.

Regards,

P.S.: I like the FLH xrk971 is referencing in Post #4, talk about solid construction.

 

[sine143]

The problem with flh.... its unlikely you will be satisfied with just one. You need that wall of mouth area, not really to "extend" LF response, but to flatten it.

Tapped horns, like the th18, othorn, etc are still impressive as singles because of their massive air displacement capabilities (down low it use the output from both sides of the cone =2x the sd per driveR.

You are going to want at least 4 flhs, so select a driver you can afford to buy 4 of.

 

[just a guy]

The problem with flh.... its unlikely you will be satisfied with just one. You need that wall of mouth area, not really to "extend" LF response, but to flatten it.

Tapped horns, like the th18, othorn, etc are still impressive as singles because of their massive air displacement capabilities (down low it use the output from both sides of the cone =2x the sd per driveR.

You are going to want at least 4 flhs, so select a driver you can afford to buy 4 of.

Tapped horns don't use both sides of the driver down low. This is a common myth that's easily disproved. I was just talking about this a few days ago, so here's a mostly copy and pasted version.

The throat side tap provides ALL the low bass, the mouth side tap only fills in a hole in response that occurs naturally in all end loaded transmission lines. Here's a quick pictorial if you are interested, showing that a tapped horn is just a transmission line with a cleverly placed mouth side tap to fill in a hole in response much higher up in freqeuncy than tuning.

First a simple end loaded tl, showing response and excursion at 1 watt.

An externally hosted image should be here but it was not working when we last tested it.

See that big nasty dip at 100 hz? That's common to all end loaded transmission lines, it's a result of harmonic resonance. To get rid of that you can move the driver down the line so it fires into a different spot in the transmission line and add stuffing, both of which amount to a net loss in potential output. Or you can turn it into a tapped horn to fill in that hole without the loss in potential output from different driver position and/or stuffing.

I'm not going to attempt to fill in that hole just yet but I am going to turn it into a tapped horn with the mouth side tap at the end of the line.

An externally hosted image should be here but it was not working when we last tested it.

See how the response is exactly the same? We moved the driver from the front face of the box to the baffle divider inside the box and the response and excursion did not change. This illustrates the fact that the bass is coming from the throat side tap, the mouth side tap does almost nothing. But we are going to move the mouth side tap now so it does something useful.

An externally hosted image should be here but it was not working when we last tested it.

Response and excursion are quite similar to the transmission line we started with but the harmonic dip is filled in to some extent and we now see the classic tapped horn response curve. The mouth side tap does almost nothing, it certainly isn't providing any bass down near tuning, and no reduction in excursion. Like I said, this isn't a good tapped horn but that's how tapped horns work.

So what does the response of the mouth side tap alone look like? Well, this is what happens when you make a transmission and line and stick the driver at the end, so it would be something like this. You've got a mess of harmonics and the front and back wave are out of phase over most of the bandwidth so you end up with a series of spikes that don't do much.

An externally hosted image should be here but it was not working when we last tested it.

But if you put it all together properly and let the simulator sort through the mess of harmonics and phase issues you get a tapped horn, the mouth side tap fills in a hole in response a regular tl would have had.

And that's really just about all there is to it. Understanding how tapped horns work really is that simple. If Danley had explained them like this in the beginning instead of his cryptic and misleading version tapped horns would be a lot better understood today.

 

[just a guy]

Hi chrapladm,

Post #1: "...I know a TH18 can best a dual 18 ported cabinet..."

Are you saying that w/ a great deal of certainty?

Yeah, in addition to the problem outlined in my post directly above, this is another big problem that we can attribute to Danley's overzealous marketing. He was quite insistent that tapped horns would always win liter for liter with no exceptions and this isn't only not true, it's almost never true.

Very early on in the collaborative tapped horn thread Iand showed this was just a bunch of marketing bull.

On paper (in a sim) the dual driver ported box is always going to win, and sometimes in real life too, as long as the ported box has ports large enough to control port compression to a reasonable amount.

 

[chrapladm]

This is one of the better documented ones by Inslowsound.

Folded bass horn - The Paper Horn by Inlow Sound

t

Thanks I forgot about that one. Will have to read more and see what size driver it needs.

Hi chrapladm,

Post #1: "...I know a TH18 can best a dual 18 ported cabinet..."

Are you saying that w/ a great deal of certainty?

Here are three simulations w/ the B&C 18TBX100, a carefully designed TH, and very quickly thrown together BR and STTL (tapped horn, bass-reflex and short-tapered transmission line). The TH is a single driver @ Eg=2.83, and the others are dual driver parallel @ Eg=2. Similar volumes (the TH is the largest) and Spl curve levels. The non-TH have lower displacement (for the same SPL), so I would assume, that they will have higher output SPL @ Xmax, they also seem to have better impulse response and group delay. So, what am I missing in the simulations?

It would be quite interesting to hear all three in the same environment.

Regards,

P.S.: I like the FLH xrk971 is referencing in Post #4, talk about solid construction.

Ya it would appear in your simulations that the BP out runs the TH. BUT I am still going to buy one driver to build one cabinet. Then have a listen.

The problem with flh.... its unlikely you will be satisfied with just one. You need that wall of mouth area, not really to "extend" LF response, but to flatten it.

Tapped horns, like the th18, othorn, etc are still impressive as singles because of their massive air displacement capabilities (down low it use the output from both sides of the cone =2x the sd per driveR.

You are going to want at least 4 flhs, so select a driver you can afford to buy 4 of.

I might want four if only using FLH's for my setup but I just want to hear the designs to compare. And if I was going to build a FLH I would only want a dual 15 or large FLH cabinet.(Single 18 ect)

Tapped horns don't use both sides of the driver down low. This is a common myth that's easily disproved. I was just talking about this a few days ago, so here's a mostly copy and pasted version.

The throat side tap provides ALL the low bass, the mouth side tap only fills in a hole in response that occurs naturally in all end loaded transmission lines. Here's a quick pictorial if you are interested, showing that a tapped horn is just a transmission line with a cleverly placed mouth side tap to fill in a hole in response much higher up in freqeuncy than tuning.

First a simple end loaded tl, showing response and excursion at 1 watt.

An externally hosted image should be here but it was not working when we last tested it.

See that big nasty dip at 100 hz? That's common to all end loaded transmission lines, it's a result of harmonic resonance. To get rid of that you can move the driver down the line so it fires into a different spot in the transmission line and add stuffing, both of which amount to a net loss in potential output. Or you can turn it into a tapped horn to fill in that hole without the loss in potential output from different driver position and/or stuffing.

I'm not going to attempt to fill in that hole just yet but I am going to turn it into a tapped horn with the mouth side tap at the end of the line.

An externally hosted image should be here but it was not working when we last tested it.

See how the response is exactly the same? We moved the driver from the front face of the box to the baffle divider inside the box and the response and excursion did not change. This illustrates the fact that the bass is coming from the throat side tap, the mouth side tap does almost nothing. But we are going to move the mouth side tap now so it does something useful.

An externally hosted image should be here but it was not working when we last tested it.

Response and excursion are quite similar to the transmission line we started with but the harmonic dip is filled in to some extent and we now see the classic tapped horn response curve. The mouth side tap does almost nothing, it certainly isn't providing any bass down near tuning, and no reduction in excursion. Like I said, this isn't a good tapped horn but that's how tapped horns work.

So what does the response of the mouth side tap alone look like? Well, this is what happens when you make a transmission and line and stick the driver at the end, so it would be something like this. You've got a mess of harmonics and the front and back wave are out of phase over most of the bandwidth so you end up with a series of spikes that don't do much.

An externally hosted image should be here but it was not working when we last tested it.

But if you put it all together properly and let the simulator sort through the mess of harmonics and phase issues you get a tapped horn, the mouth side tap fills in a hole in response a regular tl would have had.

And that's really just about all there is to it. Understanding how tapped horns work really is that simple. If Danley had explained them like this in the beginning instead of his cryptic and misleading version tapped horns would be a lot better understood today.

I dont want this to turn into a everything is better than a TH/FLH debate. I know the downfalls and am willing to live with them.

Yeah, in addition to the problem outlined in my post directly above, this is another big problem that we can attribute to Danley's overzealous marketing. He was quite insistent that tapped horns would always win liter for liter with no exceptions and this isn't only not true, it's almost never true.

Very early on in the collaborative tapped horn thread Iand showed this was just a bunch of marketing bull.

On paper (in a sim) the dual driver ported box is always going to win, and sometimes in real life too, as long as the ported box has ports large enough to control port compression to a reasonable amount.

If money were no object I would build all three cabinet designs and have a listen. BUT I dont. So for me I would like to have a single 18" FLH design to compare against the Othorn. And then I will try and have a trip to a friend who has quite a few large ported dual 18 Sound 18 "9000
cabinets to compare which to me sounds better.

I will be building a pair of Othorns regardless of this. BC218 would work great also for me but there arent any plans for a design like that. SO the search continues along with some very simple sims.

 

[CLS]

For home use?

Before evaluating the real performance, these monsters tend to overload the room. I think that is a more difficult problem and should be considered first.

For comparing the sounds of FLH, TH, and ported cab, you may see all that in the web page mentioned in post # 4.

BTW, I vote for FLH, too.

 

[just a guy]

They don't have to be monsters and they don't have to overload the room.

I've got a 100 liter flh that isn't a monster and doesn't overload the room. I could have made it even smaller and still had flat response, as you can see the response is quite flat as it is.

An externally hosted image should be here but it was not working when we last tested it.

The flh is the upper line in light green, measured inside with the mic in the horn mouth because it was winter at the time. There's no eq or filters of any kind applied, that's it's natural response.

A flh doesn't have to be big and it can have close to ruler flat response. If that's what you want.

 

[just a guy]

I dont want this to turn into a everything is better than a TH/FLH debate. I know the downfalls and am willing to live with them.

I don't know what you are talking about. In the posts you quoted I just showed how tapped horns work, and that the mouth side tap doesn't provide any output down near tuning and stated that liter for liter tapped horns don't beat ported. I didn't express any preference or claim superiority to any of them, just countered a couple of well known myths, BOTH of which were brought up and needed to be corrected.

If money were no object I would build all three cabinet designs and have a listen. BUT I dont. So for me I would like to have a single 18" FLH design to compare against the Othorn. And then I will try and have a trip to a friend who has quite a few large ported dual 18 Sound 18 "9000
cabinets to compare which to me sounds better.

I will be building a pair of Othorns regardless of this. BC218 would work great also for me but there arent any plans for a design like that. SO the search continues along with some very simple sims.

I'm not sure how that's fair. The Othorn has a ridiculously expensive 21 inch driver. Comparing a regularly priced 18 inch driver in a flh to an Othorn isn't fair at all. And then comparing both of those to some ported cabs with different drivers and probably different tuning isn't going to tell you much except which specific subwoofer you prefer. It isn't going to tell you anything about how the different alignments compare to each other.

Maybe I'm not getting the point of the comparison, but comparing 3 wildly different things isn't going to tell you much about any of them.

 

[chrapladm]

I will be using this sub for outdoors only. I dont see the point in something this large for indoors at least for me.

Just A Guy I am trying to do what I can for comparison sakes. I was already going to build a Othorn. I have the 21" already. If I had to keep costs the same I could build a dual 18 TBW100, I think thats the model, cabinet and compare.

The other option would be to design a FLH for a BC 21SW152. I only have a single driver as of now. I could at least use that driver for building purposes an listen but not A/B listen.

And yes an 18" FLH probably is not fair against the Othorn. But I was just thinking I could probably afford to buy a BC 18". Cant help but want to have a BC218 sub.

How big does a FLH get for a 21" SW152? I am thinking LARGE.

 

[sine143]

I'm coming for you Just a Guy.

Consider this. If we use the example of a backloaded horn (I used the stock "super scoop" but shrank vtc down to 3000), but shrink the rear chamber size to 3 liters (about the size of the volume of air in the cone shape)

The below pic shows the horn schematic, output of the horn alone vs overall output, and then output of the driver front face (typical sealed response falloff, plus notches for the impedance minimas, or the excursion minimas) vs overal output, and then diaphragm displacement.

We can see if we ignore the output from the front side of the driver, this horn shows classic "non reactance anulled" response (due to the lack of a rear chamber damping the output at the horn LC, and a very low compression ratio); a drooping middle of the passband, and a jackhammer peak at the low corner.

Adding a rear chamber (and increasing compression to reactance anull) to this design will smooth the response (adding to the midbass dip, and subtracting from the massive peak downlow, but when we consider this application for tapped horn use, we can utilize this massive peak at the low corner by "using the output from the front side of the cone" to "fill in the dip" in the bass between the impedance minimas.

Moving the driver into the throat allows us to reduce the distance between the front and rear wave, which both pushes the catostrophic midbass dip upwards out of the passband, AND allows up to play with the shape of the low corner spike almost exclusivly (notice increasing L45 in a tapped horn design generally increases sensitivity at the low corner).

While the "output from both sides of the cone" may not be responsible for the output of the LOW LOWs of a tapped horn (as this happens at excursion minima, there is no output from the front side of the cone here), But using the output of the rear side of the driver ABOVE the low corner excursion minima helps us fill in what would OTHERWISE be a massive dip in the middle of the passband, and the more sensitivity you can force into that area, the higher you can make that low corner sensitivity spike without "ruining" response with a massive peak down low.

 

[just a guy]

How big does a FLH get for a 21" SW152? I am thinking LARGE.

It can be as big or as small as you want it to be. But if you want serious gain compared to a ported box it has to be seriously larger than a ported box.

Anyway, here's a quick sim. I spent literally 30 seconds on this, it took longer to make the pic and host it than to do the sim. I don't have time to compare it to Othorn right now but I might later tonight. At 264 liters it should be somewhat comparable in size. I'm not suggesting it's a great idea to make it this small but you certainly could if you wanted to. Shown at 1 watt.

An externally hosted image should be here but it was not working when we last tested it.

 

[just a guy]

I'm coming for you Just a Guy.

Lol, come at me. I enjoy a good technical discussion.

I can't follow what you are showing without at least an input screen to play along with. You are talking about moving the driver around, adding chambers, etc, and I'm not even familiar with the original design. With an input screen I might be able to follow what you are describing.

 

[sine143]

I got you man. I'm bored at a gig right now so perhaps I will pm you... though emptying my inbox on the phone sucks

In the above example it was ONLY a back loaded horn, there was no moving of drivers involved in the pic I showed, just comparison of output from "horn" and "direct radiator" vs combined output, showing the output from the direct radiator has added sensitivity in the middle of the passband

EDIT

Heres the input screen btw

 

[chrapladm]

The dual ported cabinet that TB46 posted earlier beats the TH18 with an 18 Sound 18 LW2500 at Xmax. The TH18 is about 320 liters. Othorn is about 420 liters. And being a FLH with a sealed chamber I would assume the FLH would be about 100 liters larger for similar performance. Just my thinking.

 

[sine143]

Here is a FLH CHrap. SHown compared to the Othorn, both at 2 volts in. they are about the same volume *sim wise*.

 

[just a guy]

An externally hosted image should be here but it was not working when we last tested it.

Comparison didn't take long. My tiny design compared to Othorn.

I was seriously mistaken about Othorn's size, it 420 liters net compared to my tiny 264 liter flh.

To be fair though, it takes a bit upwards of 7000 watts to push the flh to xmax as shown here, the Othorn doesn't take nearly that much. But that's what happens when you undersize a flh this severely.

I can do a bit more fair comparison with a bigger and better flh if you like, but not today.