Hi, I am interested in building a Hog Scoop enclosure for the 18sound 21LW1400 speaker, similar to the design described here: https://www.freespeakerplans.com/?view=article&id=31:hog-scoop . Currently, I have two of these speakers mounted in bass reflex boxes, but I’ve noticed that the sound doesn’t seem as powerful when used outdoors.
I would like to know if the Hog Scoop design could provide more SPL compared to the bass reflex enclosures I am currently using. I am particularly interested in improving low-frequency performance and achieving a louder and clearer sound in open spaces.
Thank you in advance for your response and any suggestions you can offer regarding my project.
I would like to know if the Hog Scoop design could provide more SPL compared to the bass reflex enclosures I am currently using. I am particularly interested in improving low-frequency performance and achieving a louder and clearer sound in open spaces.
Thank you in advance for your response and any suggestions you can offer regarding my project.
It probably would provide more SPL, but it won't do much below 40Hz, judging by the horn path length.
Josh Ricci's tapped horn Othorn would go lower:
https://www.diyaudio.com/community/threads/the-othorn-tapped-horn.193418/
That said, the 18sound 21LW1400 does not have the power handling, BL, excursion as the 18Sound 21NLW9601 Josh reccommends, so won't go near as loud.
Best to compare your present cabinet to the Othorn using the Hornresp simulation program to see what the response differences would be.
The thing is, I'm not necessarily interested in very low frequencies (like around ±30 Hz); my goal is to maximize SPL, and I'm mostly interested in frequencies above 40-45 Hz. So, theoretically, if I were to build this type of enclosure, I should have a fairly high SPL outdoors with a good punch, but also some deep bass, right?
Your best bet will be to use Hornresp to simulate your driver in that cabinet.
If you want to keep your existing drivers and amplifiers, a tapped horn will net you about +6dB compared to the bass-reflex cabinets you have at the moment.
Different BLHs (back-loaded horns, like the Hog scoop) will perform differently again. Generally, though, horn subs like those are intended to be used in groups of 4+ to get the LF response where it ought to be - the horn mouth is under-sized for the LF cutoff, but using multiples together helps to fix this. Tapped horns work fine in singles.
Chris
If you want to keep your existing drivers and amplifiers, a tapped horn will net you about +6dB compared to the bass-reflex cabinets you have at the moment.
Different BLHs (back-loaded horns, like the Hog scoop) will perform differently again. Generally, though, horn subs like those are intended to be used in groups of 4+ to get the LF response where it ought to be - the horn mouth is under-sized for the LF cutoff, but using multiples together helps to fix this. Tapped horns work fine in singles.
Chris
If maximum SPL from 40 Hz and up (especially outside) is your goal, large rear (or front) loaded horns are your best bet. The Hog is basically a variation on the 18" scoop cabinet. IIRC the designer (staiper) published it in the time period when tapped horns first became popular in the DIY scene but because of the relative large horn mouth the 'tapped effect' is probably limited. Still a nice twist on the flat front scoops, of which you'll also find 21" designs.
Staiper never released a diy 21" version and the 21LW1400's magnet depth won't fit the current 18" Hog. Also , the Qts x Vas product is on the high side considering the drivers the Hog was designed for but adding a larger rear chamber would solve both those problems 😉
Staiper never released a diy 21" version and the 21LW1400's magnet depth won't fit the current 18" Hog. Also , the Qts x Vas product is on the high side considering the drivers the Hog was designed for but adding a larger rear chamber would solve both those problems 😉
However, in my opinion the 21LW1400 isn't a good driver for high spl 40...120 Hz especially not in a TH due the 4" VC and less cone stability.
Had 4 of them in BP and 2 times blown coils. Maybe it was my bad, cause they had 2x crest 8001 bridged and I some beers...was 10 years ago.
Maybe sell them and use 4x or 6x 15" chassis. Many good pro amps also run very well on 6x 15" and this is the minimum to produce the necessary pressure at outdoor in my opinion.
Had 4 of them in BP and 2 times blown coils. Maybe it was my bad, cause they had 2x crest 8001 bridged and I some beers...was 10 years ago.
Maybe sell them and use 4x or 6x 15" chassis. Many good pro amps also run very well on 6x 15" and this is the minimum to produce the necessary pressure at outdoor in my opinion.
So, I simulated an enclosure in Hornresp, and it seems fine; this is the kind of enclosure I was thinking of. What do you think? https://www.speakerplans.eu/details.php?id=4
Thank you for your suggestion. The thing is that I want to make an enclosure that is noticeable louder than a bass reflex, so I will be in peace 😀 How chris661 said in this topic, the tapped horn could give me an extra 6db, so I'm totally ok with that.
Hi! Thank you for you suggestion. I think I'm gonna make two tapped horn enclosures for these 21's that i have. I just want a noticeable pressure than a bass reflex and I'm all good 😀 Btw, what type of enclosure could give me the best performance for these speakers?
what do you think about these measurements? https://freespeakerplans.com/media/kunena/attachments/21025/IMG_20150212_183713.jpg
The throat went from 12.5 cm to 12.7 cm, while the Sd went from an approximate 1225 cm^2 to 1660 cm^2. Those ratio's seem way off, while the increase in total cabinet volume seems more in line. Luckily the horn expands quickly after the initial throat opening but seems to follow a 1 : 1.2 ratio rather than my expected 1 : 1.4 ratio.
So although not my precise cup of tea (bear in mind I haven't had HR have a look at it) not a bad stab at it.
The lack of dimensions given on this schematic diagram, make it a rough ordeal to land on the exact dimensions of the rear chamber. So the question remains, whether or not the 21LW1400 will fit in the rear chamber. From a practical perspective you could always double the baffle from the front, if the 21LW1400 so desires it. I would also take a few centimeters of the 'throat forming panel'.
So although not my precise cup of tea (bear in mind I haven't had HR have a look at it) not a bad stab at it.
The lack of dimensions given on this schematic diagram, make it a rough ordeal to land on the exact dimensions of the rear chamber. So the question remains, whether or not the 21LW1400 will fit in the rear chamber. From a practical perspective you could always double the baffle from the front, if the 21LW1400 so desires it. I would also take a few centimeters of the 'throat forming panel'.
I am new to designing speaker enclosures other than bass reflex types, and I was wondering if you could tell me what I need to consider when designing a hog scoop or Othorn enclosure, please.
The key word is compression ratio, for the 21LW1400 I would start at 2:1 (Sd: throat). Then adjust the rest of the Hog's cross sectional horn areas to reflect the increase in Sd and increase the rear chamber volume to adjust for the increase in Qes x Vas product.
The way I would go about it:
The way I would go about it:
- Put those horn parameters in Hornresp
- Fine tune
- Put the result in 3D software (I suggest Sketchup)
- Find out those horn parameters are not practically possible
- Readjust HR horn parameters untill the Sketchup sketch and HR are in agreement
Optionally:
- Gloat in the perfect design you've created
- Let the design process rest for a while
- Come back a week later only to find out there's a better way to do it
- Restart at step 5
- Simplify
- Build it
If somewhat larger size does not scare you, then a large ROAR type of enclosure could give you the added SPL you are looking for. Due to the size (21 inch) and large Vas it would become quite difficult to move around without some serious muscle. It is a split path design som it does not load the diapharm uneven, and it does add a lot of midbas efficiency for a quite pronounced attack and punch.
A potential issue I see with your driver is that it was designed for sub duty (Fs=28) and it have a modest Xmax of 9.5 and a 4" VC
For high SPL outdoors if only 2 drivers you need to design your cab for 40 or even 50 Hz, that 21" do not match.
You will need very high power 15"s and those are 500-700 per driver
So..
What abradolf says
Sell them and get 6 or 8 15"s
Stick them in a 40 to 50 tuned TH and you are in biz.
Check jbell SS15 (single sheet th tread)
Although it was designed for the 3015LF you can stick new drivers in it and sims great.
I can't remember how many drivers I have simmed in it. But I can retest tomorrow if you like.
The key here is multiples , you need more cabs for outdoors , 6 is minimum , I advice 8
Now, don't get fooled by high Xmax drivers , the price skyrocket as Xmax increase , you can have modest Xmax drivers and hit hard with 8 cabs.
There's one guy in the Single sheet Th thread ( SS15) who made 12 cabs with the 200 watts 3015lf and he was tear drop happy, flipc I think and jbell called his cab cluster flips dozen! Lol
If I was you , I sold those 21"s and get 8 15"s
And make 8 SS15"s
The SS15 only use one sheet of ply , so you will save on wood.
Later today I will sim some drivers in 6 and 8 cabs count and paste here.
The SS15 thread was really long but I have the plans in my sub folder stash 🤠
I have some other plans that I have collected and that are tuned around 40 and 45 if you wanna give em a try let me know.
Btw , how many amps you have and what they are.
For high SPL outdoors if only 2 drivers you need to design your cab for 40 or even 50 Hz, that 21" do not match.
You will need very high power 15"s and those are 500-700 per driver
So..
What abradolf says
Sell them and get 6 or 8 15"s
Stick them in a 40 to 50 tuned TH and you are in biz.
Check jbell SS15 (single sheet th tread)
Although it was designed for the 3015LF you can stick new drivers in it and sims great.
I can't remember how many drivers I have simmed in it. But I can retest tomorrow if you like.
The key here is multiples , you need more cabs for outdoors , 6 is minimum , I advice 8
Now, don't get fooled by high Xmax drivers , the price skyrocket as Xmax increase , you can have modest Xmax drivers and hit hard with 8 cabs.
There's one guy in the Single sheet Th thread ( SS15) who made 12 cabs with the 200 watts 3015lf and he was tear drop happy, flipc I think and jbell called his cab cluster flips dozen! Lol
If I was you , I sold those 21"s and get 8 15"s
And make 8 SS15"s
The SS15 only use one sheet of ply , so you will save on wood.
Later today I will sim some drivers in 6 and 8 cabs count and paste here.
The SS15 thread was really long but I have the plans in my sub folder stash 🤠
I have some other plans that I have collected and that are tuned around 40 and 45 if you wanna give em a try let me know.
Btw , how many amps you have and what they are.
Hi @maxolini, I want you to see this
. The program is WinISD. In the first picture, you can see the response of the speaker in a bass reflex enclosure (300L, 30hz). In the second picture, I quicly designed a 6th order bandpass. Although the Fs seems to be 28 hz, from my measurements and designs that i made, these included, the speaker seems to work well from 50hz +, gaining more spl in that area. Am i doing something wrong? I don't really understand what is going on.
For me, selling them is not an option...
I got an amplifier named The t.amp E-1500, working in paralel; 1 speaker channel A, 1 speaker channel B; 8 ohm. I can say that the amplifier is not a problem, it moves the cones very well without clipping, but i want that +3-6 db from the enclosure.
For me, selling them is not an option...
I got an amplifier named The t.amp E-1500, working in paralel; 1 speaker channel A, 1 speaker channel B; 8 ohm. I can say that the amplifier is not a problem, it moves the cones very well without clipping, but i want that +3-6 db from the enclosure.
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You commented that with 40 to 45 lowest freq reach you are ok, so why you get the 21"s in the 1st hand ?
The sell those option is to get more drivers to make more cabinets , you can get 2 drivers for the price of one you have or almost that , but you need more drivers not a pair.
As people have told you , you need a TH instead of BR to get more SPL , but for outside only one amp and a pair of cabinets will not cut.
You need to be realistic , you can't bend the laws of physics.
The sell those option is to get more drivers to make more cabinets , you can get 2 drivers for the price of one you have or almost that , but you need more drivers not a pair.
As people have told you , you need a TH instead of BR to get more SPL , but for outside only one amp and a pair of cabinets will not cut.
You need to be realistic , you can't bend the laws of physics.
@maxolini Well, when i first bought these speakers i wanted a bass reflex cabinet that goes as low as possible. All good. I love rebassed songs😀 Time passed and I wanted some more spl because i got used to that spl. I did research and i found that very low frequencies need more power than high frequencies in order to achieve the same spl and I tought that it's not worth it outside, so this is why i said >40hz in the beginning. The subwoofers do a great job on very low frequencies (e.g. 30hz +-). Now, the thing is that the bass reflex gives me an extra spl at very low frequencies and at frequencies >50 hz i can hear a loss in sound and i'm sure this is not because of my crossover and, by doing a new enclosure,I want the same output at low frequencies and a bit extra on 50-80-85. I can feel the deep bass, the vibration but not that impulse that you get from 80hz, maybe the tapped horn would do the trick
If you're unable to design your own or adjust an existing cabinet, go with an existing design for 21" drivers. An oldy (like the 21LW1400): 21" Superscooper It's a large rear loaded horn, so it will be one of the loudest options. Perhaps there's also a 21" paraflex or a 21" ROAR.
For those that need to know, Fs is generally not that big of an issue, certainly not the biggest. The 15ND930, one of the best kick drivers (80 Hz and up) has an Fs of 36 Hz. I recon 80 - 90 % of 18" PA drivers have an Fs near 30 Hz. As the Fs gets lower the efficiency goes down, you can counteract this with a large Vas and a low Qts, the 21LW1400 has both. Plus two will have the Sd equivalent of 4 x 15".
Personally I would get 80 Hz and up from your tops (or your kicks).
For those that need to know, Fs is generally not that big of an issue, certainly not the biggest. The 15ND930, one of the best kick drivers (80 Hz and up) has an Fs of 36 Hz. I recon 80 - 90 % of 18" PA drivers have an Fs near 30 Hz. As the Fs gets lower the efficiency goes down, you can counteract this with a large Vas and a low Qts, the 21LW1400 has both. Plus two will have the Sd equivalent of 4 x 15".
Personally I would get 80 Hz and up from your tops (or your kicks).