42 holes predrilled, countersunk, then screwed in.
About 146 to go.
meanwhile ive been doing some soldering and soldered some connectors to wires.
These will go from sub to back of the box, kinda integrated into the back panel.
From amp to the box these connectors on the left attach to the connectors integrated into the back panel.
http://i.imgur.com/O59GZi5.jpg
These kind of connectors are made for High amperage high vibration use and i can barely pull one of those apart so im not worried about them slightest.
Cant wait to play some Agape - Dead Can Dance on that thing.
About 146 to go.
meanwhile ive been doing some soldering and soldered some connectors to wires.
These will go from sub to back of the box, kinda integrated into the back panel.
From amp to the box these connectors on the left attach to the connectors integrated into the back panel.
http://i.imgur.com/O59GZi5.jpg
These kind of connectors are made for High amperage high vibration use and i can barely pull one of those apart so im not worried about them slightest.
Cant wait to play some Agape - Dead Can Dance on that thing.
I forgot to document all the things i was doing, but every side is braced with planks 2/3 of the way on each side,every seam has been glued with very liquidy type of sealant first and then sealed with patex silicone, the thing shakes wardrobes and windows easily, im very happy with the performance it gives. HOWEVER, due to error in calculations or harmonic frequency of the room or maybe nature of human hearing, somehow the sub is loudest by far at about 40Hz. Port is cut to 30cm in order to have nice internal clearance with the back wall, plan is to install a nice looking flared external extension of about 10cm and i was wondering if that would do the trick or something else is amiss.
this is current eq im running including the subwoofers sub 15Hz protection.
I have to note that i have experienced coil hitting kind of noise at about 40Hz sine wave and about 60% of the volume so i havent tested it at its loudest yet.
current eq:
this is how it roughly looks right now:
There are now lots of screws from all sides.
But back to the main problem, what could i do about it apparently being tuned to 40ish Hz not 27ish Hz.
Many thanks to all and i hope i see "just a guy" in this thread again or many more smart people that go around these forums.
Cheers!
this is current eq im running including the subwoofers sub 15Hz protection.
I have to note that i have experienced coil hitting kind of noise at about 40Hz sine wave and about 60% of the volume so i havent tested it at its loudest yet.
current eq:
this is how it roughly looks right now:
There are now lots of screws from all sides.
But back to the main problem, what could i do about it apparently being tuned to 40ish Hz not 27ish Hz.
Many thanks to all and i hope i see "just a guy" in this thread again or many more smart people that go around these forums.
Cheers!
According to my previous sims you should have a huge peak at 32 hz about 5 db higher than the rest of the passband, that's not unexpected. (but then you went an made the box shape totally different than your pics and my sim so the sim might not be perfectly accurate but still should be close enough)
It's also possible that you have a huge room mode at 40 hz or so. In that case the only real inexpensive cure (without resorting to eq) is playing with placement - move the sub around the room, try it in other rooms and outside and see if the peak goes away. It won't go away completely, as there is a natural 5 db spike in response at about 32 hz, but you might be able to make it a bit better with placement.
If you want to decrease the spike in response at 32 hz you need to filter the response or make the port longer. A lot longer. That will lower the tuning and flatten out the response. But then the sub will hit it's excursion limits with less power and less spl inside the passband.
Look at the sims I posted in post 26. None of this behavior is unexpected. It was never going to be flat down to 27 hz, it's got a huge peak at 32 hz. If you want it flatter to a lower frequency you need to eq the peak out or extend the port length which effectively lowers the tuning.
I told you from the start this was a cheap driver with a weak motor and if you put it in a ported box it would have a peaky response right above tuning unless you tune very low.
It's also possible that you have a huge room mode at 40 hz or so. In that case the only real inexpensive cure (without resorting to eq) is playing with placement - move the sub around the room, try it in other rooms and outside and see if the peak goes away. It won't go away completely, as there is a natural 5 db spike in response at about 32 hz, but you might be able to make it a bit better with placement.
If you want to decrease the spike in response at 32 hz you need to filter the response or make the port longer. A lot longer. That will lower the tuning and flatten out the response. But then the sub will hit it's excursion limits with less power and less spl inside the passband.
Look at the sims I posted in post 26. None of this behavior is unexpected. It was never going to be flat down to 27 hz, it's got a huge peak at 32 hz. If you want it flatter to a lower frequency you need to eq the peak out or extend the port length which effectively lowers the tuning.
I told you from the start this was a cheap driver with a weak motor and if you put it in a ported box it would have a peaky response right above tuning unless you tune very low.
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If you want to find the actual tuning, run sine waves through it, start at a low frequency and increase 1 hz by 1 hz until the cone almost stops moving and the vent is blowing a lot of air. That's your tuning frequency. Don't do this at very high power or you will blow the driver.
I see you went for a 30 cm long port. In that case your response should be somewhere between the 20 cm and 40 cm sims in post 26.
If you want to get rid of the humped up response right above tuning completely your port will have to be a lot longer - maybe 60 - 80 cm, and this will lower tuning significantly but it will get rid of the humped response.
But if the problem is a room mode changing the tuning won't fix that, it will only make it marginally better.
I see you went for a 30 cm long port. In that case your response should be somewhere between the 20 cm and 40 cm sims in post 26.
If you want to get rid of the humped up response right above tuning completely your port will have to be a lot longer - maybe 60 - 80 cm, and this will lower tuning significantly but it will get rid of the humped response.
But if the problem is a room mode changing the tuning won't fix that, it will only make it marginally better.
Yes i know i completely changed the design but this ended up being 10 times cheaper so i just couldnt make myself spend that kind of money.
Pic in my last post shows how much i EQ 40Hz down in order to make it not "boomy AF" but that deep extension under it is so nice once you hear it.
Its like a sound of an earthquake, you cant even be sure the sound is coming from the room not a volcano erupting, still it is A LOT quieter at 27 than 40.
i could try putting 70cm of same tube externally tomorrow over day and see if 40Hz bump disappears or goes lower. I mean it couldnt be a permanent solution having a huge box in the room with another 70cm pipe coming out of it. Btw this box has slightly larger volume so even with 30cm port it is still a bit above 250l.
Dunno, it shakes windows and wardrobes at 40 easily but id just rather move all that power 20hz lower. lol
Talking about its extrusion limits, if it would extrude too much and i would hear any coil hitting sounds i will adjust amplifier gain so it never happens in any scenario. Just hope i can bring it down somehow without opening the box up since its glued, siliconed then drilled with 200+ screws, but hey- if it is necessary i could open it and add an l joint of 160mm if i find it and extend it internally another 40cm
Opened for ideas, and id like to repeat that im still happy with the results once i level out its response via equalizer to remove that annoying 40Hz bump, but if we could make it better then lets make it better. Who knows, I might even put a SoundStream Tarantula T4-15 in that thing soon.
Cheers
Pic in my last post shows how much i EQ 40Hz down in order to make it not "boomy AF" but that deep extension under it is so nice once you hear it.
Its like a sound of an earthquake, you cant even be sure the sound is coming from the room not a volcano erupting, still it is A LOT quieter at 27 than 40.
i could try putting 70cm of same tube externally tomorrow over day and see if 40Hz bump disappears or goes lower. I mean it couldnt be a permanent solution having a huge box in the room with another 70cm pipe coming out of it. Btw this box has slightly larger volume so even with 30cm port it is still a bit above 250l.
Dunno, it shakes windows and wardrobes at 40 easily but id just rather move all that power 20hz lower. lol
Talking about its extrusion limits, if it would extrude too much and i would hear any coil hitting sounds i will adjust amplifier gain so it never happens in any scenario. Just hope i can bring it down somehow without opening the box up since its glued, siliconed then drilled with 200+ screws, but hey- if it is necessary i could open it and add an l joint of 160mm if i find it and extend it internally another 40cm
Opened for ideas, and id like to repeat that im still happy with the results once i level out its response via equalizer to remove that annoying 40Hz bump, but if we could make it better then lets make it better. Who knows, I might even put a SoundStream Tarantula T4-15 in that thing soon.
Cheers
Do not discount the possibility that you could have a strong room mode at 40 hz, so try different locations for the sub. Put it in a spot that produces a natural null at 40 hz in the room and your problem might go away.
If you look at Fletcher Munsen curves you will see that if you sweep a flat signal from 27 to 40 hz, 40 hz is SUPPOSED to sound a lot louder due to our human perception of relative frequency loudness.
If you want it to be AUDIBLY flat to low frequencies it certainly won't MEASURE flat, as we don't hear 27 and 40 hz the same way - 40 is supposed to be louder by about 12 db (depending on how loud it's playing).
You should never ever hear coil hitting sounds. This indicates a huge problem.
Usually this happens at frequencies below tuning as the driver is unloaded below tuning and it's almost the same as running the driver naked without a box at all at those frequencies. That's what the high pass filter is for, to protect the driver mechanically below tuning at frequencies where it isn't loaded by the box. You should simulate your box and that will tell you what frequency to set the high pass filter at and how steep it needs to be.
If the high pass filter is properly set and your excursion is too high INSIDE the passband (above tuning) the only cure for that is to turn the volume knob down or eq the frequencies that cause the problem down.
If you want a longer port but don't want to take the box apart, work on it through the driver hole. Add an elbow and an extension. It might be easier if you completely remove the old port, fix it up outside the box and then reinstall it. This should all be possible without taking the box apart.
If you look at Fletcher Munsen curves you will see that if you sweep a flat signal from 27 to 40 hz, 40 hz is SUPPOSED to sound a lot louder due to our human perception of relative frequency loudness.
If you want it to be AUDIBLY flat to low frequencies it certainly won't MEASURE flat, as we don't hear 27 and 40 hz the same way - 40 is supposed to be louder by about 12 db (depending on how loud it's playing).
You should never ever hear coil hitting sounds. This indicates a huge problem.
Usually this happens at frequencies below tuning as the driver is unloaded below tuning and it's almost the same as running the driver naked without a box at all at those frequencies. That's what the high pass filter is for, to protect the driver mechanically below tuning at frequencies where it isn't loaded by the box. You should simulate your box and that will tell you what frequency to set the high pass filter at and how steep it needs to be.
If the high pass filter is properly set and your excursion is too high INSIDE the passband (above tuning) the only cure for that is to turn the volume knob down or eq the frequencies that cause the problem down.
If you want a longer port but don't want to take the box apart, work on it through the driver hole. Add an elbow and an extension. It might be easier if you completely remove the old port, fix it up outside the box and then reinstall it. This should all be possible without taking the box apart.
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Doing it through a driver hole is a damn good idea and completely possible due to its dimensions. great advice all around.
I am aware of the curve of human hearing, im hugely into headphones and audiophile in that sense but speakers and subwoofers i have no experience whatsoever, i just feel like the box is actually tuned to that freq somehow, sounds like a generic 40Hz bass boost on a crappy phone.(reason to believe this is amount of things shaking in the room at 40 vs 30Hz, i know you need much more power to generate same spl at lower frequencies but still...) Its probably calculated wrong unfortunately since this "shitty" driver has almost no real data to calculate anything from.
I can add some extension externally- see if it is worth it and then doing it on the inside with L pipes. Im all about that earthquake mode.
Wish i found that tarantula sub for sale earlier because now i would have a "real" driver to work with that has real data, not to mention it is rated for 1000w rms and has much better xmax and am sure its suspension is designed much better to make coil hitting impossible and things like that.
Before all that of course i will try to move the box around the room a bit to see if there is any difference, right now i can tell you there are hotspots and coldspots of bass and i dont like that even though the hot spot is right where im sitting. Besides, who has enough space to move that kind of a box around the room to try it from all sides Ill do my best. Plan is to redecorate this room and have the sub directly behind me or even maybe beneath the computer table where i listen to music.
I did some calculations with filling the box with that wolly kind of thing and if im not mistaken it is as if i increased the box volume by 10% right? That should make almost no difference.
If im wrong and it has much larger impact imma buy that pillow stuffing thing tomorrow first thing after work and fill the crap out of it.
Kind regards
I am aware of the curve of human hearing, im hugely into headphones and audiophile in that sense but speakers and subwoofers i have no experience whatsoever, i just feel like the box is actually tuned to that freq somehow, sounds like a generic 40Hz bass boost on a crappy phone.(reason to believe this is amount of things shaking in the room at 40 vs 30Hz, i know you need much more power to generate same spl at lower frequencies but still...) Its probably calculated wrong unfortunately since this "shitty" driver has almost no real data to calculate anything from.
I can add some extension externally- see if it is worth it and then doing it on the inside with L pipes. Im all about that earthquake mode.
Wish i found that tarantula sub for sale earlier because now i would have a "real" driver to work with that has real data, not to mention it is rated for 1000w rms and has much better xmax and am sure its suspension is designed much better to make coil hitting impossible and things like that.
Before all that of course i will try to move the box around the room a bit to see if there is any difference, right now i can tell you there are hotspots and coldspots of bass and i dont like that even though the hot spot is right where im sitting. Besides, who has enough space to move that kind of a box around the room to try it from all sides
Ill do my best. Plan is to redecorate this room and have the sub directly behind me or even maybe beneath the computer table where i listen to music. I did some calculations with filling the box with that wolly kind of thing and if im not mistaken it is as if i increased the box volume by 10% right? That should make almost no difference.
If im wrong and it has much larger impact imma buy that pillow stuffing thing tomorrow first thing after work and fill the crap out of it.
Kind regards
Someone somewhere said "when your port blows most air thats the frequency your box is tuned at", now i dont know if that is true because my port blows most air at 20Hz. I moved it 4 meters over and changed its direction so it shoots towards my back and now it still peaks at (update*) 48Hz like crazy and and 38 its silent compared to 48Hz and then it gets a bit better at 30Hz. Input appreciated! only wish i got more of it.
This forum has been very helpful, im definitely donating at my next paycheck.
This forum has been very helpful, im definitely donating at my next paycheck.
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hello goa604, i had few macaudio/magnat speakers similar to yours, but i used them only as stereo midbass, active crossed with adittional mono subwoofers,even for small pa use, never expected too much low bass out of them actualy so i was very satisfied.
i bet your tuning is too low actualy. any means of measuring response with microphone and software like arta?
have fun!
i bet your tuning is too low actualy. any means of measuring response with microphone and software like arta?
have fun!
Sorry tonitonitoni, there is no way of doing all that since im running usb dac amp with line out and its own driver.
I mean there could be a theoretical chance of it being tuned way too low and what im experiencing as 48Hz peak might actually be
this thing right here (red) and the tuning im aiming for is simply non existent in this case(blue).
Well easiest thing to do is add another 10cm on the ouside and thats what im about to go cut in the garage and give an update in about 30-60 minutes.
Cheers.
I mean there could be a theoretical chance of it being tuned way too low and what im experiencing as 48Hz peak might actually be
this thing right here (red) and the tuning im aiming for is simply non existent in this case(blue).
Well easiest thing to do is add another 10cm on the ouside and thats what im about to go cut in the garage and give an update in about 30-60 minutes.
Cheers.
Tried with another 10cm, tried with 50cm ABSOLUTELY no difference. I find that very odd.
Still peaking strong at 48Hz.
Can i assume im unlucky and it is just the frequency at which my room resonates?
Any other ideas?
Hope there are solutions to more dB in sub 30Hz other than more watts and eq my room resonant frequency down. What is the point of 1000w rms if i wouldnt even be able to experience it without -16dB at 40ish Hz,
Right now i have it at -10dB
Still peaking strong at 48Hz.
Can i assume im unlucky and it is just the frequency at which my room resonates?
Any other ideas?
Hope there are solutions to more dB in sub 30Hz other than more watts and eq my room resonant frequency down. What is the point of 1000w rms if i wouldnt even be able to experience it without -16dB at 40ish Hz,
Right now i have it at -10dB
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That certainly sound like a strong room mode. Take the sub outside and listen to it. Ideally measure it. Then you'll know what's contributed by the sub and what's contributed by the room.
The increase in volume from stuffing is with sealed subs. With ported subs it's just going to make your low frequency output weaker.
BTW, you should also try plugging the port and see if you like that better. It will take most of the low bass away but it might become more listenable.
Someone somewhere said "when your port blows most air thats the frequency your box is tuned at", now i dont know if that is true because my port blows most air at 20Hz. I moved it 4 meters over and changed its direction so it shoots towards my back and now it still peaks at (update*) 48Hz like crazy and and 38 its silent compared to 48Hz and then it gets a bit better at 30Hz. Input appreciated! only wish i got more of it.
This forum has been very helpful, im definitely donating at my next paycheck.
Still sounds like room effects.
It's all about the cone motion, when the cone motion almost stops that's your tuning frequency. I just mentioned it would be blowing a lot of air through the port at that frequency as a side note. You can't judge tuning by airflow alone, the most telling characteristic will be the cone motion being a minimum at tuning.
Taking the sub outside and listening to it and simulating your current box are your two best tools at this point, assuming you can't measure.
Also, maybe consider the fact that your amp might not be flat - it might have a boost at your problem frequencies. But it certainly sounds like a room mode problem.
Also, maybe consider the fact that your amp might not be flat - it might have a boost at your problem frequencies. But it certainly sounds like a room mode problem.
yeah funny thing about that, that amp im using has a 40hz boost mode where i select from 0 to 12 db, but i of course left it at 0. It would be highly unlikely that the potentiometer or a switch or however its made is broken but ill still consider it down the road as im trying to get the sound im looking for.
The weird thing is that even when i plug the port it sounds the same, same peak, same lack of sound under 30. God damnit i even tried adding 50cm of port and it still sounded the same. Its as if the box doesnt matter at all, port lenght doesnt mater at all.
Im wondering right now if i could have just built 40x40x40cm box and put it in there and not deal with a cabinet i can literally fit in.
That kind of a small box could even fit on my desk ffs.
thanks
The weird thing is that even when i plug the port it sounds the same, same peak, same lack of sound under 30. God damnit i even tried adding 50cm of port and it still sounded the same. Its as if the box doesnt matter at all, port lenght doesnt mater at all.
Im wondering right now if i could have just built 40x40x40cm box and put it in there and not deal with a cabinet i can literally fit in.
That kind of a small box could even fit on my desk ffs.
thanks
64L box experiment
Hi there g: Making a 64L box (40x40x40, cm) should be easy to do. Test it outside like JAG suggested and see if the results are the same as your mega ported/sealed box. ...regards, Michael
Did you seal the existing box joints as well as screwing them, a tiny leak can cause retuning of the box. ...Mike
Hi there g: Making a 64L box (40x40x40, cm) should be easy to do. Test it outside like JAG suggested and see if the results are the same as your mega ported/sealed box. ...regards, Michael
Did you seal the existing box joints as well as screwing them, a tiny leak can cause retuning of the box. ...Mike
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Every time you post it sounds more and more like a room mode issue. Everybody has room modes (except people that don't listen in small domestic rooms) and we all have to deal with these issue. My modes are strong peaks at 60, 110 and 220 hz. It can make you want to bash your head on the wall, or just turn the music off.
I can assure you that box size and tuning does matter - it matters a lot - but at the same time the room is everything and we all have our own rooms to deal with.
I can assure you that box size and tuning does matter - it matters a lot - but at the same time the room is everything and we all have our own rooms to deal with.
That's an option, but it would exclude the thunderous high 20s frequencies he's after completely.
I still recommend dragging the existing box outside and seeing if the problem at 40 hz goes away. If it goes away it doesn't matter what kind of box you put in that room, it's going to have a 40 hz peak unless he finds a spot in the room that nulls 40 hz, treats the room extensively, uses multiple subs or uses eq to crush it.
Multiple subs, Earl Getties
Hi there g: As JAG mentioned, multiple subs can elevate room mode situations, information can be found by Googling Dr. Earl Gettes site. Sorry I missed your post #39 wherein you mentioned sealing joints. Also, is the driver properly sealed by gasket material. ...regards, Michael
Hi there g: As JAG mentioned, multiple subs can elevate room mode situations, information can be found by Googling Dr. Earl Gettes site. Sorry I missed your post #39 wherein you mentioned sealing joints. Also, is the driver properly sealed by gasket material. ...regards, Michael
just a guy: Yes ive been reading about room frequency responses till now and it looks like you are right. i unfortunately cant bring this setup outside that easily but i might try it in near future. Thing is if i moved it out on the balcony id have to connect it somehow through a window to the amp psu and a computer since im running that high pass filter to not damage the sub on a computer digitally. Box weighting 30ish kilos certainly doesnt help and it is just impossible to carry it alone due to dimensions.
Would opening a window that makes 30% of one wall perhaps change things enough to change room frequency response? I have a huge window and perhaps i can confirm that the room is to blame.
j.michael droke : yup everything is silicone sealed and i even checked with a feather if there is any air turbulence around the seams. Nothing seems to be leaking. But you got me interested and i will check tomorrow again when its daylight outside. How would a leak change tuning, got any links i could read up?
You know what, i dont think i have anything between the sub and the box- no gasket. i could silicone the **** out of it and put it back if you think that could be causing such problems.
Would opening a window that makes 30% of one wall perhaps change things enough to change room frequency response? I have a huge window and perhaps i can confirm that the room is to blame.
j.michael droke : yup everything is silicone sealed and i even checked with a feather if there is any air turbulence around the seams. Nothing seems to be leaking. But you got me interested and i will check tomorrow again when its daylight outside. How would a leak change tuning, got any links i could read up?
You know what, i dont think i have anything between the sub and the box- no gasket. i could silicone the **** out of it and put it back if you think that could be causing such problems.
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