The RTA screen was to demonstrate what can be seen looking at music, not representative of anything in particular, other then the general low end "haystack" often seen.
Measurement was using the built in mic on an iMac between two Tannoy PBM-6.5 crossed at 70Hz BW24, nearest sub one meter away on some random track that came up when the screen was captured.
To see what the recording was actually doing, I would have had to push more than one radio button 😉
I got two panels of free 15mm OSB so cutting it up to make a test version of the subwoofer, and my two different options for the top; get a feel for the woodworking needed here; play with my brand new nailgun... and maybe even figure out which top design I want to do (vented or unvented... or 2 drivers unvented)...
And I swear this will be a temporary test cabinet, and not the final version.
And I swear this will be a temporary test cabinet, and not the final version.
I don't know if you got amplifiers already, but given those batteries I would be wanting to use that directly. Converting that to 12V and then a car amp converting 12V to probably like 30-40V internally or whatever adds a layer of inefficiency due to the DC-DC conversion, even if the output is Class D.
There are some Fosi and Aiyima and such that use external computer power supplies, 32V or 48V etc which you could connect directly. I am far from expert in all that; I'd post another thread asking "what amps could I power from these batteries?"
@head_unit i already have https://store.sure-electronics.com/product/614 this 2x300+1x500 amp which i'm happy with for now. Once all the speakers are built, and my DSP tuned in, I could see myself upgrading and asking that.
Do you think the performance of that amp will be reasonable?
Do you think the performance of that amp will be reasonable?
Just make sure you run at 4 or 3 ohms to get the rated wattage from the board ....and you feed 50V with enough amperage , otherwise you will not get what the specs read:
- Output Power
- 500W@3Ohm 50V DC THD+N 10%
- 312W@3Ohm 50V DC THD+N 1%
Got a first draft of the sub and tops. A few necessary design changes:
At some point the width went from 22" to 23" and no longer fits in the trailer.
When designing I threw the driver cutout circle and went 'i'll center that later' and never did... but built to the plan.
More importantly this is far quieter than I want it to be. I'm hoping part of that might be input related - I had previously had a pre-amp between the mixer and the amp; but using DSP now, that took the pre-amp out of the path (and now I need a 3rd preamp channel; it was previously a passive one).
But I'm running 8 amp speakers which is going to be hard to run regardless. With 50V input voltage, I think I might need to change my amps (despite my assurance at the previous step). Or change my design - I was pondering returning the 15" driver and getting two 12" drivers... but don't have particularly good ideas for which to do. (Driver weight should be kept below 25lb total (and 15 lb is ideal). And $350 total ($250 preferred)).
Open to suggestions!
At some point the width went from 22" to 23" and no longer fits in the trailer.
When designing I threw the driver cutout circle and went 'i'll center that later' and never did... but built to the plan.
More importantly this is far quieter than I want it to be. I'm hoping part of that might be input related - I had previously had a pre-amp between the mixer and the amp; but using DSP now, that took the pre-amp out of the path (and now I need a 3rd preamp channel; it was previously a passive one).
But I'm running 8 amp speakers which is going to be hard to run regardless. With 50V input voltage, I think I might need to change my amps (despite my assurance at the previous step). Or change my design - I was pondering returning the 15" driver and getting two 12" drivers... but don't have particularly good ideas for which to do. (Driver weight should be kept below 25lb total (and 15 lb is ideal). And $350 total ($250 preferred)).
Open to suggestions!
The sub is ridiculous, I mean...
The driver itself doesn't look like a sub...first rule of a sub is that it's got be in-efficient, more on the 80-85 dB/W than 90-95 dB/W figure, so a heavy cone, the suspensions ( spider & external roll ) and a long throw ( at least 10 mm...) that are requested for heavy duty operation at low Hertz.
The cabinet should be heavy and sound proof, because you'd want only the cone to move.
I don't see a subwoofer driver nor a heavy cabinet.
The boxes...I would have taken a 8"...dunno, the proportions are for the eye...and the ear.
The driver itself doesn't look like a sub...first rule of a sub is that it's got be in-efficient, more on the 80-85 dB/W than 90-95 dB/W figure, so a heavy cone, the suspensions ( spider & external roll ) and a long throw ( at least 10 mm...) that are requested for heavy duty operation at low Hertz.
The cabinet should be heavy and sound proof, because you'd want only the cone to move.
I don't see a subwoofer driver nor a heavy cabinet.
The boxes...I would have taken a 8"...dunno, the proportions are for the eye...and the ear.
@picowallspeaker the speaker details are in this post - https://www.diyaudio.com/community/...peaker-trailer-in-atlanta.416766/post-7890915
I'mc urious what you would recommend with the given requirements (lightweight, as it is a portable (bicycle trailer) system:
ideally fitting within 22x28x14", but not much bigger
Driver weight should be kept below 25lb total (and 15 lb is ideal).
Driver cost below $350 total ($250 preferred)).
The underlying system is a bicycle trailer soundsystem; the entire system has to be under 100 lb (including tops, battery, amp, dsp, etc.). I have multiple 48V batteries (actual 46-52v) that I want to use for powering the system.
I would love to hear what alternative suggestions you would have!
I'mc urious what you would recommend with the given requirements (lightweight, as it is a portable (bicycle trailer) system:
ideally fitting within 22x28x14", but not much bigger
Driver weight should be kept below 25lb total (and 15 lb is ideal).
Driver cost below $350 total ($250 preferred)).
The underlying system is a bicycle trailer soundsystem; the entire system has to be under 100 lb (including tops, battery, amp, dsp, etc.). I have multiple 48V batteries (actual 46-52v) that I want to use for powering the system.
I would love to hear what alternative suggestions you would have!
Well, just the speaker chassis weights a lot, then the boxes occupy volume.
If you want a lot of power in small containers, the speakers should be the top performers. A neodymium 8" midwoofer is over 200$
Subwoofer falls in the 500$
Then you've got to put them into operation, make 'em not lose power by radiating just frontally and not thru the cabinet walls.
Viceversa, you could open the back of the three boxes and experiment with directivity, so you save 3 baffles in weight.
The subwoofer needs reinventing...
If you want a lot of power in small containers, the speakers should be the top performers. A neodymium 8" midwoofer is over 200$
Subwoofer falls in the 500$
Then you've got to put them into operation, make 'em not lose power by radiating just frontally and not thru the cabinet walls.
Viceversa, you could open the back of the three boxes and experiment with directivity, so you save 3 baffles in weight.
The subwoofer needs reinventing...
@picowallspeaker What do you mean by 'open the back of the three boxes and experiment with directivity"?
I'm fine compromising quality (bass extension and power) to meet my size/space/weight requirements.
I'm fine compromising quality (bass extension and power) to meet my size/space/weight requirements.
So your amp only puts out ~113 watts at 8 ohms.
If your amp could do around 450 watts, output would be ~+6dB, which would be a lot less quiet 😉 .
The speaker would sound as loud at twice the distance as it does now.
Hey @cycrev I feel like I'm obliged to contribute, but apologies for not following along... let's talk about the where you landed with the build, which you seem to be disappointed with
What driver did you use for the bass box?
And after the dimension error, have you confirmed the box volume and tuning as a "sense check" based on the build?
I would expect a pro audio bass driver, in a ~100L box tuned to ~45Hz, should make a decent amount of noise with the amps you have...
Maybe the signal path needs some attention, especially since you mentioned addition of DSP and removal of preamp
At a guess, I would suggest the amp isn't getting a hot enough signal for it to drive the speaker as expected
Can you list the components in your signal chain and how they're connected?
And maybe strip everything down to basics, do some testing with a AC RMS multimeter and see what you can do to get a 10V sine wave out of the amp and run the speaker with that. Once you can get it outputting to a level you expect, you can add back the DSP and tops to build out the system
as for picowallspeaker's "advice", there's nothing really useful there that relates to this specific project
What driver did you use for the bass box?
And after the dimension error, have you confirmed the box volume and tuning as a "sense check" based on the build?
I would expect a pro audio bass driver, in a ~100L box tuned to ~45Hz, should make a decent amount of noise with the amps you have...
Maybe the signal path needs some attention, especially since you mentioned addition of DSP and removal of preamp
At a guess, I would suggest the amp isn't getting a hot enough signal for it to drive the speaker as expected
Can you list the components in your signal chain and how they're connected?
And maybe strip everything down to basics, do some testing with a AC RMS multimeter and see what you can do to get a 10V sine wave out of the amp and run the speaker with that. Once you can get it outputting to a level you expect, you can add back the DSP and tops to build out the system
as for picowallspeaker's "advice", there's nothing really useful there that relates to this specific project
Build a JBELL ss15, it make a lot of noise for its size and since is not tuned that low around 50hz, you do not need a 500 bucks driver...
it is a 15" ? right ?
a TH tuned to around 50hz like the SS15 will outperform a BR box that is tuned to 30hz using the same driver
so...
since you are using a budget driver and budget low wattage amp
you need to convert every watt to SPL
the SS15 will help to do that ....
its tuning is not low (more like a midbass cab) not a sub.
if you can get a second hand 3015LF you will be golden
otherwise... maybe save some bucks to get one new (3015LF)
since it is a neodymium driver it is vert light.
otherwise you will be disappointed like youa re now...
and pretty sure you will want to destroy those cabinets and make firewood
it is a 15" ? right ?
a TH tuned to around 50hz like the SS15 will outperform a BR box that is tuned to 30hz using the same driver
so...
since you are using a budget driver and budget low wattage amp
you need to convert every watt to SPL
the SS15 will help to do that ....
its tuning is not low (more like a midbass cab) not a sub.
if you can get a second hand 3015LF you will be golden
otherwise... maybe save some bucks to get one new (3015LF)
since it is a neodymium driver it is vert light.
otherwise you will be disappointed like youa re now...
and pretty sure you will want to destroy those cabinets and make firewood
The SS15 is definitely too big for me. The THAM15 is slightly too big (but potentially doable)... indeed I feel like a 12" might be a better fit?
I wouldn't trust this (free) OSB in a firepit - who knows what glues they used!
I wouldn't trust this (free) OSB in a firepit - who knows what glues they used!
Curious.
Do you go with the 113 L box tuned to 45 Hz with the Odeum 15N driver? If so, at 250W the output should look like the following, with lots of upper bass:
That level should be noticeable.
@100W, the response should look something like this. 118dB is loud, but it's not as loud as it would be at 250W 🙂
To go louder than that with that driver, you'll need to use a higher-order design like a TH, but that's likely going to require a larger box.
e.g. a simple single-expansion TH (like the MTH30, sized to fit your driver), will get you a few more dB with the same 250W input, but will require a box that's twice the volume (once you take the volume displaced by the internal panels into consideration):
However, given that amount of volume to work with, I'd consider just adding another driver in parallel in a vented box taking up the same volume as the TH. The total impedance will drop to 4 ohms, allowing your amp to deliver more power (theoretically double the amount), which will result in this:
If we're stuck with 250W, then the result with the two drivers in the same volume occupied by the TH should be something like this:
If you do want to try the SS15 TH out, check to see if your existing driver will work in it (just plug your driver's parameters into the corresponding Hornresp model). Alternatively, you could use my BOXPLAN workbook to design an "SS" type TH of your own. Size however will likely end up being over 200L net, almost double the volume of your current vented box.
Given those size restrictions for the subwoofer, to get more output you'll need to:
1. Use a driver with a lot more Vd (Sd x Xmax) than the Dayton Audio Odeum 15N
2. Use an amplifier that can swing a lot more voltage into the subwoofer.
Something like a B&C 15TBW100-4 driven by a car audio class D amp capable of delivering at least 1.5kW into 4 ohms might do it. Of course, that solution is going to be a LOT more expensive ... !
I was looking at the qcc3034 thread last night. It's a bluetooth or line connection preamp, with dsp. One of the dsp functions was bass alteration. In part, a kind of scaling. It could take 20hz, and move it to 40hz, while 40 became 55. 55hz moved to 65, and 65hz to 70. You get the idea. It was definable, but in essence, everything could be moved upwards. This is how baby BT speakers don't go quiet when the 40hz tone drops. They just move it where the speaker can work.
Further tuning of the bass such as adding harmonic reproduction was provided. So you could move the 20hz you cant' play, up to 40hz you can. While also echoing it at 80 and perhaps 120hz. Thickening up the bass you have.
This all sounds a bit rubbish at first read, but just take your household speaker outside for a moment, and try to play some 50hz tones. I have set up parties in the woods, and the bass is just lost. You need heaps of power. Yet some kid with his JBL BT thing can do perfectly well.
If you bring together the portable speaker dsp tricks, with high sensitivity neo drivers and class D efficiency, you might find box and battery sizes shrink, while bass increases.
I just watched a nobsound review on wiliston? audio youtube channel. Couple of 3255 are they? did 300w each on his showpiece amp dyno. I think we can find 3255 duel amps with qcc3034 sections easy enough. I just bought an electronics consumer grade 3034 board myself, for a bit over a tenner.
Perhaps someone with more background than reading one thread can crime in 🙂
Edit: Also think about just buying the JBL thing, because you need to beat it by miles, or your efforts will look a bit pointless. You know, when some girl with one in her front basket comes past you.
Further tuning of the bass such as adding harmonic reproduction was provided. So you could move the 20hz you cant' play, up to 40hz you can. While also echoing it at 80 and perhaps 120hz. Thickening up the bass you have.
This all sounds a bit rubbish at first read, but just take your household speaker outside for a moment, and try to play some 50hz tones. I have set up parties in the woods, and the bass is just lost. You need heaps of power. Yet some kid with his JBL BT thing can do perfectly well.
If you bring together the portable speaker dsp tricks, with high sensitivity neo drivers and class D efficiency, you might find box and battery sizes shrink, while bass increases.
I just watched a nobsound review on wiliston? audio youtube channel. Couple of 3255 are they? did 300w each on his showpiece amp dyno. I think we can find 3255 duel amps with qcc3034 sections easy enough. I just bought an electronics consumer grade 3034 board myself, for a bit over a tenner.
Perhaps someone with more background than reading one thread can crime in 🙂
Edit: Also think about just buying the JBL thing, because you need to beat it by miles, or your efforts will look a bit pointless. You know, when some girl with one in her front basket comes past you.
Hm...the directions are still vague.I read the other thread, I've already seen those OSB panels one week ago, and yes, the system didn't seem pretentious so I passed over.
So I don't wonder if the ear isn't pleased with that.
With a total power like that available, say 600-800 Wh, every thing has got to be maximized.
OP likes psytrance. I blew my tweeters with that. But you've got Seleniums, which are 108 dB.
So I 'd chose a mid bass closer to that in order not to lose precious dBs. 10 dB on the tweeter are gonna be burnt anyway...
The closer I think you may find is some little beast 99 dB midrange, but we'll, if you spend 500€ on a midrange you'd want to recalibrate the tweeter and the adiacenti way either ( a 3 way, more efficient than a 2 way)
Then the sub.
This has got to be 4 Ω
If it distorts, who cares, but it's got to deliver the power (peaks).
Did I put a lot of 'got' ?! Really?!
So I don't wonder if the ear isn't pleased with that.
With a total power like that available, say 600-800 Wh, every thing has got to be maximized.
OP likes psytrance. I blew my tweeters with that. But you've got Seleniums, which are 108 dB.
So I 'd chose a mid bass closer to that in order not to lose precious dBs. 10 dB on the tweeter are gonna be burnt anyway...
The closer I think you may find is some little beast 99 dB midrange, but we'll, if you spend 500€ on a midrange you'd want to recalibrate the tweeter and the adiacenti way either ( a 3 way, more efficient than a 2 way)
Then the sub.
This has got to be 4 Ω
If it distorts, who cares, but it's got to deliver the power (peaks).
Did I put a lot of 'got' ?! Really?!