Hi guys,
The bug has bitten again.
I've got some rather nice bookshelf speakers (2-way FAST with a FE126eN and a TB W6-1139 per side, biamped).
They'll hit 40Hz, but I'd like more right at the bottom end for movies and the like.
So, the logical solution is a subwoofer.
I've come across threads where a JBL car sub (or two) has been used in a tapped horn-style enclosure, and wondered where that might take me.
I have access to the GTO1214 (seems to be the popular one), and have played around with TQWPs in Hornresp, as I can't get a decent result when trying tapped horns.
I can get 120dB to ~20Hz (corner loaded) from either a ported box or a TQWP. In fact, the ported box appears to go a little louder. However, I am suspicious of the Xmax ratings for these drivers, so I doubt they'll hit 120dB.
Power isn't a huge issue - I'll be using my bass guitar amp (once I've bypassed the 30Hz low-cut) that'll swing 200v p/p @8ohm when bridged. Long term power would be more like 3-500w, but the headroom's nice to have.
So, a few questions.
Are the JBL car subs worth playing with?
For those of you that have played with them, how far can you push them before they start putting out harmonics?
I'd like to hit 20Hz clean in a small room. Will a single 12" be sufficient? (I expect so, but would like confirmation either way)
Now, room placement isn't something I can play around with - it'll be in the corner of the room, underneath my desk.
The maximum size I'd accept is around 150L, but smaller would be better: I've been toying with the idea of throwing away maximum SPL by going for a small sealed cabinet with plenty of eq. I know this probably wouldn't get the most out of the driver, but I'd save of money (and time) by getting one of those prefab 35L sealed cabinets.
Guidance would be much appreciated
Chris
The bug has bitten again.
I've got some rather nice bookshelf speakers (2-way FAST with a FE126eN and a TB W6-1139 per side, biamped).
They'll hit 40Hz, but I'd like more right at the bottom end for movies and the like.
So, the logical solution is a subwoofer.
I've come across threads where a JBL car sub (or two) has been used in a tapped horn-style enclosure, and wondered where that might take me.
I have access to the GTO1214 (seems to be the popular one), and have played around with TQWPs in Hornresp, as I can't get a decent result when trying tapped horns.
I can get 120dB to ~20Hz (corner loaded) from either a ported box or a TQWP. In fact, the ported box appears to go a little louder. However, I am suspicious of the Xmax ratings for these drivers, so I doubt they'll hit 120dB.
Power isn't a huge issue - I'll be using my bass guitar amp (once I've bypassed the 30Hz low-cut) that'll swing 200v p/p @8ohm when bridged. Long term power would be more like 3-500w, but the headroom's nice to have.
So, a few questions.
Are the JBL car subs worth playing with?
For those of you that have played with them, how far can you push them before they start putting out harmonics?
I'd like to hit 20Hz clean in a small room. Will a single 12" be sufficient? (I expect so, but would like confirmation either way)
Now, room placement isn't something I can play around with - it'll be in the corner of the room, underneath my desk.
The maximum size I'd accept is around 150L, but smaller would be better: I've been toying with the idea of throwing away maximum SPL by going for a small sealed cabinet with plenty of eq. I know this probably wouldn't get the most out of the driver, but I'd save of money (and time) by getting one of those prefab 35L sealed cabinets.
Guidance would be much appreciated
Chris
since you are mating up with bookshelf speakers, I assume refrigerator size cabinets are out.
Check the thread on avs and grab the hornresp inputs.. but I think lilmike's 25hz insubnia works with the jbl804 when built 8" internal width... don't remember for sure, and too lazy to search.... I know I've built one without the bottom fold for a MCM 55.2421..
Reed Exodus Anarchy 25hz Tapped Horn
Check the thread on avs and grab the hornresp inputs.. but I think lilmike's 25hz insubnia works with the jbl804 when built 8" internal width... don't remember for sure, and too lazy to search.... I know I've built one without the bottom fold for a MCM 55.2421..
Reed Exodus Anarchy 25hz Tapped Horn
If my memory serves me correct I managed to get 24hz-1db or so out of the W6-1139. It is possible to go that low with no eq with this driver in the correct enclosure.
Very impressive sound for the size. But as they say "There's no replacement for displacement", although the W6-1139 can pump some air, and it takes abuse too. If you want to build something like that you need to depend on room gain though, or the FR will run away from it SPL wise.
Since you mentioned GTO1214
http://www.diyaudio.com/forums/subwoofers/160879-build-your-own-2x12-th-kraken-212-th.html
There is the Kraken 212 with 2 of them, and the kraken 112 with 1 GTO1214 and the Kraken 210 with 2 GTO1014
The plans for the 112 and 210 is on page 10
http://www.diyaudio.com/forums/subwoofers/160879-build-your-own-2x12-th-kraken-212-th.html
There is the Kraken 212 with 2 of them, and the kraken 112 with 1 GTO1214 and the Kraken 210 with 2 GTO1014
The plans for the 112 and 210 is on page 10
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#1 What music do you have that reaches 20? 25 to 30 is fine unless you listen to heavy organ or distorted special effects.
#2 120 dB at 20 and the word "cheap" do not mesh.
#3 120 dB at 20 Hz. I hope you live at least a mile form anyone else, or they will be very upset with you.
#4 120 dB at 20 Hz, you will need it louder as you will have no hearing in no time.
A lot of people seem to go for deep and loud bass forgetting totally about distortion. One more problem that means not cheap. It makes a bigger difference than most understand.
#2 120 dB at 20 and the word "cheap" do not mesh.
#3 120 dB at 20 Hz. I hope you live at least a mile form anyone else, or they will be very upset with you.
#4 120 dB at 20 Hz, you will need it louder as you will have no hearing in no time.
A lot of people seem to go for deep and loud bass forgetting totally about distortion. One more problem that means not cheap. It makes a bigger difference than most understand.
#5, A single sub in the corner is very problematic, as it is a different distance from the sub to the mains. This means you will have phase nulls no matter what you do. The steeper the crossover the better you will do. B3 won't cut it. LR4 closer, but I would go for LR6.
#6 In the corner means yo will gave a lot of room gain. Be very careful thinking you want a flat response from crossover down. You don't. This is like I prefer low Q ( .5 or so) sealed subs. They flat work better in a real room.
#7, I will never give up my old 830500's because of their low distortion. I drive them with a Parasound HCA series amp. Yes, it made a difference.
#6 In the corner means yo will gave a lot of room gain. Be very careful thinking you want a flat response from crossover down. You don't. This is like I prefer low Q ( .5 or so) sealed subs. They flat work better in a real room.
#7, I will never give up my old 830500's because of their low distortion. I drive them with a Parasound HCA series amp. Yes, it made a difference.
Yup. Valid question yesterday, still valid today. How many people have actually run their music collection through a spectrum analyzer with a hold feature? I have. I'll stand by my 30Hz number.
The OP mentioned he wants to hear movie effects, which there are plenty of going well below 20 Hz.
I have hundreds of pop CDs that have plenty of signal in the low 20 Hz range.
I have a Mackie HRS120 sub which uses a 12” speaker and a 12” passive radiator in a 61 liter box which has response +/- 1 dB from 20 Hz to 150 Hz, maximum free field SPL 117 dB.
In room, it can do around 120 dB at 20 Hz clean, it certainly causes no hearing damage (though high speakers at 120 dB certainly would) and normal house construction cuts the level down outside by around 20 dB, neighbors have no complaints.
I do agree with your point #2, though "cheap" is a relative term.
Using a pair of Lab 12 or TC Epic 12 may or may not be considered cheap, but can easily do 120 dB in room at 20 Hz with the amp power the OP has available.
Art
I can pick out lots of tracks that break that rule. Perhaps your collection can't. We don't know what others might have in theirs, either.
My point is that we should back off from the suggestion that "nobody needs anything below 30 hz" and neglecting to add the most important reason for making that statement, because my personal collection doesn't demand it."
To be clear, 120dB at 20Hz isn't a target - there would, as has been pointed out, be many angry people nearby.
That said, its usually my stereo that gets used for parties around here, so being able to go loud is useful - never before have I seen this amplifier (120w/ch @4ohm, driving the woofers) clip, but we managed it. I'd consider this to be abusive toward the woofers - they're rated for 50w. Clearly, something bigger is needed for the low end.
I'm currently in university accomodation (ie, a big block of flats). The rooms are fairly well soundproofed, but I know that I won't be able to get anywhere near the full capability out of this subwoofer often.
So, most of the time it'll be idling along, filling in where the little speakers fall off. Occasionally (once or twice per week, when we have a few drinks here before heading into town), I'd like to be able to turn everything up and not have to panic about <35Hz stuff coming along.
A rough calculation of SPLs...
Each TB sub is ~82dB@1w. Plus a bit of room gain, minus a bit of bafflestep.
100w input = 102dB per side @1m
Total SPL = 108dB.
When in a sealed cabinet, 10mm one-way travel gives ~95dB @20Hz.
Hornresp seems to think you gain ~12dB by corner loading.
107dB @20Hz, 20mm p/p excursion.
That seems like a lot of excursion - has anyone torture tested these drivers to see how their performance compares to JBL's claims?
I'm off to bed - its been a long day.
Cheers
Chris
That said, its usually my stereo that gets used for parties around here, so being able to go loud is useful - never before have I seen this amplifier (120w/ch @4ohm, driving the woofers) clip, but we managed it. I'd consider this to be abusive toward the woofers - they're rated for 50w. Clearly, something bigger is needed for the low end.
I'm currently in university accomodation (ie, a big block of flats). The rooms are fairly well soundproofed, but I know that I won't be able to get anywhere near the full capability out of this subwoofer often.
So, most of the time it'll be idling along, filling in where the little speakers fall off. Occasionally (once or twice per week, when we have a few drinks here before heading into town), I'd like to be able to turn everything up and not have to panic about <35Hz stuff coming along.
A rough calculation of SPLs...
Each TB sub is ~82dB@1w. Plus a bit of room gain, minus a bit of bafflestep.
100w input = 102dB per side @1m
Total SPL = 108dB.
When in a sealed cabinet, 10mm one-way travel gives ~95dB @20Hz.
Hornresp seems to think you gain ~12dB by corner loading.
107dB @20Hz, 20mm p/p excursion.
That seems like a lot of excursion - has anyone torture tested these drivers to see how their performance compares to JBL's claims?
I'm off to bed - its been a long day.
Cheers
Chris
Part of engineering is to be realistic about requirements. These pages are full of absurd "requirements" because somebody read them somewhere. One can get much further in an engineering effort if they set reasonable and informed goals.
That's not made any more, is it? I think the current crop of Mackie subs only go down to 35Hz.
Do you think it was the passive radiator that allowed the low, low response? Or a special 12" driver? That's kinda crazy in a 2 foot box.
Originally Posted by weltersys
I have a Mackie HRS120 sub which uses a 12” speaker and a 12” passive radiator in a 61 liter box which has response +/- 1 dB from 20 Hz to 150 Hz, maximum free field SPL 117 dB.
The passive radiator allows a low tuning in a small box, and the driver has a lot of excursion. It was the only sub I heard in a big showroom that could really put some boot to it below 35 Hz, which I needed to accurately mix modern electronic music, the Tannoy PBM 6.5 worked OK for a lot of older music, but 50 Hz does not cut it any more..
Of the approximately 50 speakers I own, the Tannoy PBM 6.5 and Mackie HRS120 are the only ones not DIY .
Art
I have a Mackie HRS120 sub which uses a 12” speaker and a 12” passive radiator in a 61 liter box which has response +/- 1 dB from 20 Hz to 150 Hz, maximum free field SPL 117 dB.
I bought the sub used, don't know if it is still in production.
The passive radiator allows a low tuning in a small box, and the driver has a lot of excursion. It was the only sub I heard in a big showroom that could really put some boot to it below 35 Hz, which I needed to accurately mix modern electronic music, the Tannoy PBM 6.5 worked OK for a lot of older music, but 50 Hz does not cut it any more..
Of the approximately 50 speakers I own, the Tannoy PBM 6.5 and Mackie HRS120 are the only ones not DIY .
Art
The JBL GTO 1214
I just installed one in my 88 litre (3.1 cubic foot) home theater sub box with an 18 inch passive radiator tuned to around 22Hz. Ran a 20Hz test tone at clipping with my small 120 watt sub amp and it was clean. It's use is for home theater and has plenty of oomph down low.
Other folks use them in 18Hz tapped horns at very high power levels, they hold up and work well. I use an SPL calculator that gives a 5dB boost for a wall and 8dB total for corner placement. Assuming 93dB for sensitivity with two JBLs, it returns 119.8dB loaded in a corner at 120 watts. If using two, get the dual voice coil version, wire the coils in series then two in parallel to get the 4 ohm load.
The 1214 was initially used by my son as a sealed box car sub with a 150 watt amplifier. A great driver that can handle sealed, ported, band pass or horn loading and holds the specs JBL puts on the T/S sheets.
I just installed one in my 88 litre (3.1 cubic foot) home theater sub box with an 18 inch passive radiator tuned to around 22Hz. Ran a 20Hz test tone at clipping with my small 120 watt sub amp and it was clean. It's use is for home theater and has plenty of oomph down low.
Other folks use them in 18Hz tapped horns at very high power levels, they hold up and work well. I use an SPL calculator that gives a 5dB boost for a wall and 8dB total for corner placement. Assuming 93dB for sensitivity with two JBLs, it returns 119.8dB loaded in a corner at 120 watts. If using two, get the dual voice coil version, wire the coils in series then two in parallel to get the 4 ohm load.
The 1214 was initially used by my son as a sealed box car sub with a 150 watt amplifier. A great driver that can handle sealed, ported, band pass or horn loading and holds the specs JBL puts on the T/S sheets.
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