What are the general pros/cons about tapped horns? Is it a problem that one part of the sound is delayed by the horns lenght? Will it make the sound less tight?
How much delay does my tops need?
Thanks
Last edited:
Pros:
- You get a lot of air moving for a small amount of watts input, and unlike front loaded horns you get to feel the movement from both sides of the cone.
- They're very flexible with the sort of drivers you can use in them, accepting cheaper drivers, and with less risk of damage to drivers when driven hard (front loaded horns can tear up drivers with weaker cones and motors)
- They're almost as efficient as a front loaded horn (T48, 1850 horn), but without the problem of needing lots of them to achieve low frequency extension. Just one tapped horn on it's own can be sufficient, which greatly enhances the flexibility of applications for your system.
- Unlike front loaded horns, no delay is needed for the tops.
Cons:
- They won't have quite such a tight and solid impact as a front loaded horn, but it's not as bad as you imagine it might be, and it definitely doesn't mean they can't be very punchy. It's similar to the difference between sealed box and vented enclosures. Sealed is tighter but you need lots of them to really get the low frequencies going.
- The available free designs for large format PA drivers aren't without their flaws and eccentricities. The same can be said of all free designs, but as tapped horns are relatively newer tech, so the range of available free designs is a little less advanced.
- For absolute fidelity you can probably do better with a good front loaded horn, but they have a whole other set of compromises to contend with, and especially outdoors are liable to feel thinner for anything approaching the portability of a tapped equivalent, and in singles/pairs? As you discovered, almost unusable.
- They don't like to be crossed high to the midtop. You want to cross them way before that first big dip in the response.
Another option worth considering is the CB-18 Cyclops.
It's a slightly bigger enclosure than the THAM18 but people who've built it report being very satisfied, and you can see just from looking at the design why that could be. The labyrinth of panels on the inside of the box makes it incredibly well braced internally, so the enclosure will be a lot more 'dead' at high power levels, which translates to small efficiency gains (a few tenths of a dB) and a marginally tighter sound.
These are an attempt at modelling the Cyclops in Hornresp that I found on Google, from another diyaudio forum member, but how accurate they are I'm not sure.
- You get a lot of air moving for a small amount of watts input, and unlike front loaded horns you get to feel the movement from both sides of the cone.
- They're very flexible with the sort of drivers you can use in them, accepting cheaper drivers, and with less risk of damage to drivers when driven hard (front loaded horns can tear up drivers with weaker cones and motors)
- They're almost as efficient as a front loaded horn (T48, 1850 horn), but without the problem of needing lots of them to achieve low frequency extension. Just one tapped horn on it's own can be sufficient, which greatly enhances the flexibility of applications for your system.
- Unlike front loaded horns, no delay is needed for the tops.
Cons:
- They won't have quite such a tight and solid impact as a front loaded horn, but it's not as bad as you imagine it might be, and it definitely doesn't mean they can't be very punchy. It's similar to the difference between sealed box and vented enclosures. Sealed is tighter but you need lots of them to really get the low frequencies going.
- The available free designs for large format PA drivers aren't without their flaws and eccentricities. The same can be said of all free designs, but as tapped horns are relatively newer tech, so the range of available free designs is a little less advanced.
- For absolute fidelity you can probably do better with a good front loaded horn, but they have a whole other set of compromises to contend with, and especially outdoors are liable to feel thinner for anything approaching the portability of a tapped equivalent, and in singles/pairs? As you discovered, almost unusable.
- They don't like to be crossed high to the midtop. You want to cross them way before that first big dip in the response.
Another option worth considering is the CB-18 Cyclops.
It's a slightly bigger enclosure than the THAM18 but people who've built it report being very satisfied, and you can see just from looking at the design why that could be. The labyrinth of panels on the inside of the box makes it incredibly well braced internally, so the enclosure will be a lot more 'dead' at high power levels, which translates to small efficiency gains (a few tenths of a dB) and a marginally tighter sound.
These are an attempt at modelling the Cyclops in Hornresp that I found on Google, from another diyaudio forum member, but how accurate they are I'm not sure.
Pros:
- You get a lot of air moving for a small amount of watts input, and unlike front loaded horns you get to feel the movement from both sides of the cone.
- They're very flexible with the sort of drivers you can use in them, accepting cheaper drivers, and with less risk of damage to drivers when driven hard (front loaded horns can tear up drivers with weaker cones and motors)
- They're almost as efficient as a front loaded horn (T48, 1850 horn), but without the problem of needing lots of them to achieve low frequency extension. Just one tapped horn on it's own can be sufficient, which greatly enhances the flexibility of applications for your system.
- Unlike front loaded horns, no delay is needed for the tops.
Cons:
- They won't have quite such a tight and solid impact as a front loaded horn, but it's not as bad as you imagine it might be, and it definitely doesn't mean they can't be very punchy. It's similar to the difference between sealed box and vented enclosures. Sealed is tighter but you need lots of them to really get the low frequencies going.
- The available free designs for large format PA drivers aren't without their flaws and eccentricities. The same can be said of all free designs, but as tapped horns are relatively newer tech, so the range of available free designs is a little less advanced.
- For absolute fidelity you can probably do better with a good front loaded horn, but they have a whole other set of compromises to contend with, and especially outdoors are liable to feel thinner for anything approaching the portability of a tapped equivalent, and in singles/pairs? As you discovered, almost unusable.
- They don't like to be crossed high to the midtop. You want to cross them way before that first big dip in the response.
Another option worth considering is the CB-18 Cyclops.
It's a slightly bigger enclosure than the THAM18 but people who've built it report being very satisfied, and you can see just from looking at the design why that could be. The labyrinth of panels on the inside of the box makes it incredibly well braced internally, so the enclosure will be a lot more 'dead' at high power levels, which translates to small efficiency gains (a few tenths of a dB) and a marginally tighter sound.
These are an attempt at modelling the Cyclops in Hornresp that I found on Google, from another diyaudio forum member, but how accurate they are I'm not sure.
Thank you so much for this info. If you look at the tham18 response. What do you think is the first real dip? Where can I cross it? I was hoping for a 100hz
Well, really the first dip, period. I was just trying to distinguish it from the first unavoidable dip (as with the Cyclops response).
100Hz will work, it just won't be optimal. It's that dip centered on 155Hz you want to avoid featuring as much as possible. It seems like 130Hz or so is where it really starts to fall off a cliff. You could try a steeper crossover slope, or even asymmetrical slopes (rolling off the bass faster than the tops come in), but you can definitely get it somewhere around 100Hz and it'll be fine. It won't make or break the system if you can't stretch to 90 but it might help if you can.
100Hz will work, it just won't be optimal. It's that dip centered on 155Hz you want to avoid featuring as much as possible. It seems like 130Hz or so is where it really starts to fall off a cliff. You could try a steeper crossover slope, or even asymmetrical slopes (rolling off the bass faster than the tops come in), but you can definitely get it somewhere around 100Hz and it'll be fine. It won't make or break the system if you can't stretch to 90 but it might help if you can.
Also one other con of tapped horns I've been thinking about lately after reading the ROAR18 thread, (where at least one user is very motivated to highlight the possible failings of the design), is that there may be some indoor spaces where the room modes excite the peaks and troughs already inherent in the design, and there may also be issues with the peaks becoming more pronounced when they're playing at max volume, due to power compression issues.
While front loaded horns frequency response tends to smooth out considerably when it has extra solid surfaces to bounce off like walls and floors etc, tapped horns don't seem to enjoy quite such a pronounced smoothing effect, and they're sometimes quite peaky to begin with, so you've got a risk of encountering a room that might be not play well with the design.
But this is going considerably past my understanding so it's mostly speculation, and the response of the Fane Colossus looks pretty smooth in the THAM anyway.
While front loaded horns frequency response tends to smooth out considerably when it has extra solid surfaces to bounce off like walls and floors etc, tapped horns don't seem to enjoy quite such a pronounced smoothing effect, and they're sometimes quite peaky to begin with, so you've got a risk of encountering a room that might be not play well with the design.
But this is going considerably past my understanding so it's mostly speculation, and the response of the Fane Colossus looks pretty smooth in the THAM anyway.
You're starting to scare me off haha. Soundgear - Orbit 4 Now Available - Introductory Offer!! is the speaker these will play with. 2 on each side. There is a frequency response. It looks like I might do a less steep roll-off at 80hz instead
Well, the scariest part was the suggestion that when running at full power, a driver can exhibit a large spike in average impedance - as much as double - and this was used as a rule of thumb to see how that would affect the response.
In reality it's probably not quite so severe, and in any case that Fane can take peaks of more than 4000w so you'll never be driving it near to full power.
If you double the impedance of the Fane driver, modelled with 4 enclosures (which is equivalent to one enclosure indoors loaded to a corner), it does get a bit more peaky than usual.
If you call it flat at 85Hz, then it's +3.5dB 55Hz, and +3dB at 130Hz.
But that's really not a problem, except if you're in a room that happens to accentuate a trough at 85Hz. Which might happen sometimes. You could fix it in those cases with EQ, and you would want to be adjusting for room modes with EQ anyway when used indoors, but it just makes that job a touch more difficult.
But it really only matters when driving them at maximum power which they'll never see, so I'm probably overplaying the issue, but it is something to be aware of.
Those Orbit midtops look amazing. What an absolute bargain!
In reality it's probably not quite so severe, and in any case that Fane can take peaks of more than 4000w so you'll never be driving it near to full power.
If you double the impedance of the Fane driver, modelled with 4 enclosures (which is equivalent to one enclosure indoors loaded to a corner), it does get a bit more peaky than usual.
If you call it flat at 85Hz, then it's +3.5dB 55Hz, and +3dB at 130Hz.
But that's really not a problem, except if you're in a room that happens to accentuate a trough at 85Hz. Which might happen sometimes. You could fix it in those cases with EQ, and you would want to be adjusting for room modes with EQ anyway when used indoors, but it just makes that job a touch more difficult.
But it really only matters when driving them at maximum power which they'll never see, so I'm probably overplaying the issue, but it is something to be aware of.
Those Orbit midtops look amazing. What an absolute bargain!
Last edited:
Hmmm. I'm actually a bit "turned off" about this tham18 now. I played around with it, and it actually says that it will exceed max displacement at with only 200w at 57-60hz
How well does horns like the 1850 perform indoor?
Or maybe even Selenium HB1808 (single version)No apologies, no remorse with geeks. ;-)
I mean, that If you see the cone excursion peak with 200w - at, or around its impedance peak - then it's pretty normal and healthy. The speaker is extremely efficient there, and needs only so low to play loud. With full power, you'd propably approach 140+ db there, if the driver could mechanically handle, which is nonsense. Not doable.
I mean, that If you see the cone excursion peak with 200w - at, or around its impedance peak - then it's pretty normal and healthy. The speaker is extremely efficient there, and needs only so low to play loud. With full power, you'd propably approach 140+ db there, if the driver could mechanically handle, which is nonsense. Not doable.
It's not at all normal for an 18" cone to reach peak excursion at 200w!
You have the sim wrong, I don't know how. The Fane Colossus reaches 6mm xmax in the THAM18 with 200w. It takes 800w to reach the full 12mm.
Maybe you're working with RMS watts? 200w RMS, 800w peak with a 6dB crest factor.
And this is actually more the fault of the Fane than the THAM18. It has 22.4 BL which is quite low. If it had 28 BL then maybe you could put 1200 or 1500w into each box, but at that level you begin to encounter issues with power compression, losing maybe 1dB or more of the 2.5dB you gain from the extra power.
If you want more excursion capacity and higher BL, another good 18" option is the BMS 18s450 with ~15mm xmax (conservatively rated by BMS as 12, but up next to the Fane it has 15 xmax) http://www.lean-business.co.uk/eshop/bms-18s450-18-1200-watt-speaker-4-vc-95-db-8-ohm-p-2593.html
You can probably put 2500 Watts into that driver in the THAM, but do you actually need that much? 6x 18" subs fed with 15000 watts will cater for several thousand people.
And your overall performance when you give them less power will be worse. I mean your distortion might be a bit lower and 1dB or so less loss from power compression, but the drivers just won't be moving near enough to their full capacity, and won't be physically shifting as much air for the same output level. I think there's something basically enjoyable about the sound of a bass driver at or around it's excursion limit. Maybe that's just me. Still, for anything up to 5000 watts of amp power and 1000+ people you're
better with the Fanes, imo, especially if you've got a good deal on them.
1850 horns work just fine indoors, although people do complain about front loaded horns 'throwing' bass to the back of the room (or into the carpark), so there are some downsides. It's outdoors you need to worry about for the same reason as the T48's underperformed. Outdoors they'll need a lot of power and a large stack to get moving in the low frequencies.
You have the sim wrong, I don't know how. The Fane Colossus reaches 6mm xmax in the THAM18 with 200w. It takes 800w to reach the full 12mm.
Maybe you're working with RMS watts? 200w RMS, 800w peak with a 6dB crest factor.
And this is actually more the fault of the Fane than the THAM18. It has 22.4 BL which is quite low. If it had 28 BL then maybe you could put 1200 or 1500w into each box, but at that level you begin to encounter issues with power compression, losing maybe 1dB or more of the 2.5dB you gain from the extra power.
If you want more excursion capacity and higher BL, another good 18" option is the BMS 18s450 with ~15mm xmax (conservatively rated by BMS as 12, but up next to the Fane it has 15 xmax) http://www.lean-business.co.uk/eshop/bms-18s450-18-1200-watt-speaker-4-vc-95-db-8-ohm-p-2593.html
You can probably put 2500 Watts into that driver in the THAM, but do you actually need that much? 6x 18" subs fed with 15000 watts will cater for several thousand people.
And your overall performance when you give them less power will be worse. I mean your distortion might be a bit lower and 1dB or so less loss from power compression, but the drivers just won't be moving near enough to their full capacity, and won't be physically shifting as much air for the same output level. I think there's something basically enjoyable about the sound of a bass driver at or around it's excursion limit. Maybe that's just me. Still, for anything up to 5000 watts of amp power and 1000+ people you're
better with the Fanes, imo, especially if you've got a good deal on them.
1850 horns work just fine indoors, although people do complain about front loaded horns 'throwing' bass to the back of the room (or into the carpark
), so there are some downsides. It's outdoors you need to worry about for the same reason as the T48's underperformed. Outdoors they'll need a lot of power and a large stack to get moving in the low frequencies.
Last edited:
The other thing to note is that the BMS driver and other seriously high power options will test the build quality of the enclosure to it's absolute limits. If you're anything less than 100% confident that you're getting a top notch solid build for your enclosures it would be a safer bet to take a lower powered driver.
The thread on Xoc's 18" tapped horn further down the page on this forum is worth a read if you've got the time. From the first page there's some interesting discussion about panel resonance and bracing, and it's quite similar to the THAM. A bit bigger I think, and digs deeper, but otherwise not a design I'm familiar with. Perhaps another option to consider. If you're thinking of building tapped horns for PA use you'll learn a lot in that thread.
The thread on Xoc's 18" tapped horn further down the page on this forum is worth a read if you've got the time. From the first page there's some interesting discussion about panel resonance and bracing, and it's quite similar to the THAM. A bit bigger I think, and digs deeper, but otherwise not a design I'm familiar with. Perhaps another option to consider. If you're thinking of building tapped horns for PA use you'll learn a lot in that thread.
It's not at all normal for an 18" cone to reach peak excursion at 200w!
You have the sim wrong, I don't know how. The Fane Colossus reaches 6mm xmax in the THAM18 with 200w. It takes 800w to reach the full 12mm.
Maybe you're working with RMS watts? 200w RMS, 800w peak with a 6dB crest factor.
And this is actually more the fault of the Fane than the THAM18. It has 22.4 BL which is quite low. If it had 28 BL then maybe you could put 1200 or 1500w into each box, but at that level you begin to encounter issues with power compression, losing maybe 1dB or more of the 2.5dB you gain from the extra power.
If you want more excursion capacity and higher BL, another good 18" option is the BMS 18s450 with ~15mm xmax (conservatively rated by BMS as 12, but up next to the Fane it has 15 xmax) http://www.lean-business.co.uk/eshop/bms-18s450-18-1200-watt-speaker-4-vc-95-db-8-ohm-p-2593.html
You can probably put 2500 Watts into that driver in the THAM, but do you actually need that much? 6x 18" subs fed with 15000 watts will cater for several thousand people.
And your overall performance when you give them less power will be worse. I mean your distortion might be a bit lower and 1dB or so less loss from power compression, but the drivers just won't be moving near enough to their full capacity, and won't be physically shifting as much air for the same output level. I think there's something basically enjoyable about the sound of a bass driver at or around it's excursion limit. Maybe that's just me. Still, for anything up to 5000 watts of amp power and 1000+ people you're
better with the Fanes, imo, especially if you've got a good deal on them.
1850 horns work just fine indoors, although people do complain about front loaded horns 'throwing' bass to the back of the room (or into the carpark
I am no expert with Hornresp. I simply typed in the data published on Martinssons blog. And then added a couple of drivers. And now actually. I'm playing around with the RCF LF18G401 driver and it actually shows better sensitivity. And is almost completely flat. No weird peaks. Especially when stacking 6:
Black: RCF
Grey: Fane
I have a great price on the Fane, but I can probably get a discount on the RCF as well. What do you think about this?
I also entered the data exactly from Martinsson's blog and have simmed the THAM18 several times before so I'm sure I didn't make a mistake. Maybe you could show a screenshot of the input screen?
I really wouldn't get too hung up on those peaks. You're talking about +/- 0.75dB. That's literally inaudible in that frequency range. You could do double blind tests with a flat one and the 'bumpy' one and ask people which was the flat response and the results would barely correlate with reality.
The RCF has 8.5mm xmax versus the Fane's 12 so it's no contest really.
The thing about what I mentioned with the room modes exciting already existing peaks and troughs, is that no matter what, the room modes will be the biggest part of the problem, and that counts for literally all speakers - horn loaded, sealed, reflex, etc - those modes can boost some frequencies by 12dB while leaving others unaffected, and if you're unlucky enough that the frequency they boost is already peaky then it's even worse news, but that 1dB difference will be the least of your worries.
The other advantage of the Fane is that it's 1200w RMS vs 900w on the RCF (I'm getting a strange sense of deja vu), so that means less power compression and also means a less bumpy response at high volume.
So actually given the small discrepancy in predicted response between the two drivers, when playing at party levels the power compression and associated impedance gains of the RCF will likely balance out the difference in response between the two drivers. (if not entirely then at least significantly, enough to render what is already something of a non-issue, even less of one)
I really wouldn't get too hung up on those peaks. You're talking about +/- 0.75dB. That's literally inaudible in that frequency range. You could do double blind tests with a flat one and the 'bumpy' one and ask people which was the flat response and the results would barely correlate with reality.
The RCF has 8.5mm xmax versus the Fane's 12 so it's no contest really.
The thing about what I mentioned with the room modes exciting already existing peaks and troughs, is that no matter what, the room modes will be the biggest part of the problem, and that counts for literally all speakers - horn loaded, sealed, reflex, etc - those modes can boost some frequencies by 12dB while leaving others unaffected, and if you're unlucky enough that the frequency they boost is already peaky then it's even worse news, but that 1dB difference will be the least of your worries.
The other advantage of the Fane is that it's 1200w RMS vs 900w on the RCF (I'm getting a strange sense of deja vu), so that means less power compression and also means a less bumpy response at high volume.
So actually given the small discrepancy in predicted response between the two drivers, when playing at party levels the power compression and associated impedance gains of the RCF will likely balance out the difference in response between the two drivers. (if not entirely then at least significantly, enough to render what is already something of a non-issue, even less of one)
Last edited:
Yeah haha. Thanks again. I'm just very easily alerted about this whole thing. It is a big investment, and I've already done sooo much research. I had some guy help me redesign the MHB-4818 before I actually realised that the horn would be soooo impractical. I think I'm pretty much locked in. I can get the Fane drivers for a very good price. Around 234 gbp piece with shipping
I think I'll stop the questions and start building soon
Well don't take me as an authority on all this whatever you do you can see I'm kind of fumbling my way through this stuff myself.
The MHB-4818 is a ridiculously huge enclosure. Unnecessarily large for what it does.
Before definitively pulling the trigger on the THAM's though I still think it might be worth a look at the Xoc 18" 35Hz tapped horn thread I mentioned.
TH-18 Flat to 35hz! (Xoc1's design)
Hornresp data on the 5th post down. It's not actually flat to 35Hz and it looks like a somewhat more advanced build. And it's larger of course.
The thing about the THAM18 though, above these other designs, is it's an easy build. That counts for a lot for reasons I mentioned about the strain of a high power driver on
an enclosure with less than optimal build quality. Less complexity, less to go wrong.
Getting the enclosure walls solid and free of vibrations is in many ways more important than the actual acoustic properties of the design.
you can see I'm kind of fumbling my way through this stuff myself.The MHB-4818 is a ridiculously huge enclosure. Unnecessarily large for what it does.
Before definitively pulling the trigger on the THAM's though I still think it might be worth a look at the Xoc 18" 35Hz tapped horn thread I mentioned.
TH-18 Flat to 35hz! (Xoc1's design)
Hornresp data on the 5th post down. It's not actually flat to 35Hz and it looks like a somewhat more advanced build. And it's larger of course.
The thing about the THAM18 though, above these other designs, is it's an easy build. That counts for a lot for reasons I mentioned about the strain of a high power driver on
an enclosure with less than optimal build quality. Less complexity, less to go wrong.
Getting the enclosure walls solid and free of vibrations is in many ways more important than the actual acoustic properties of the design.
1850 horns work just fine indoors, although people do complain about front loaded horns 'throwing' bass to the back of the room (or into the carpark
My experience is that FLHs don't need a lot of power, but you absolutely need a stack. At least a half stack - half as much mouth area as is theoretically needed to support the path length determined cutoff. Or more. If you don't, the TH wins. Or even good old ported boxes. Also, the driver(s) need to be properly matched to the horn or you give up both the efficiency advantage and much of the mutual coupling. The T48 isn't very well designed - and the 1850 with the right drivers would do better. Down to 45 hz, of course. In at least a pair and preferably a quad to do what they are supposed to. The T48's mouth is just too small and you need about 12. Stop at 4 and it leaves you unimpressed.
As far as them throwing to the back - that's one of the advantages. You don't have to stand right in front of the subs to get the full impact. Makes the sound very full over a football field size area. The fact that you can still hear the 30 or 40 hz content a quarter or half mile away certainly makes your system stand out from all the rest.
Hemi>
No, it´s perfectlz´y normal.You can try on yourself with Honresp and Max SPL tool in the menu when/where you have "Accoustical power" graph active. YOu add in 200W and 12mm of Xmax to the prompt window, and it will be excursion limited. I tried this on 200ll bassreflex box. All that is pretty normal.
In real world, you don´t push 200W at those frequencies to the speaker, due to the high impedance of that speaker in those frequencies.
This is true sensitivity of the speaker in the bassreflex box when fed exactly 1W across the frequency spectrum.
PicFront - truesensitivity.jpg
Very different to what you get with lets say 2,83V constant voltage feeding. I´d rather add this comparison as a decisive factor absout speaker efficiency, not the classical sensitivity graphs everybody does.
Also it´s obvious that if you feed 200W in that peak, you´d reach over 130db of spl, which is again, not true.
No, it´s perfectlz´y normal.You can try on yourself with Honresp and Max SPL tool in the menu when/where you have "Accoustical power" graph active. YOu add in 200W and 12mm of Xmax to the prompt window, and it will be excursion limited. I tried this on 200ll bassreflex box. All that is pretty normal.
In real world, you don´t push 200W at those frequencies to the speaker, due to the high impedance of that speaker in those frequencies.
This is true sensitivity of the speaker in the bassreflex box when fed exactly 1W across the frequency spectrum.
PicFront - truesensitivity.jpg
Very different to what you get with lets say 2,83V constant voltage feeding. I´d rather add this comparison as a decisive factor absout speaker efficiency, not the classical sensitivity graphs everybody does.
Also it´s obvious that if you feed 200W in that peak, you´d reach over 130db of spl, which is again, not true.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.