I think I may have missed something. Which box design have you decided to go with?
Because with those graphs I'd have picked the UM12 and built 2 boxes [ if room and WAF allowed] for the extra dB
Because with those graphs I'd have picked the UM12 and built 2 boxes [ if room and WAF allowed] for the extra dB
I, currently, am going for the 2: 15in in sealed 2.5 cubic feet.
The box without the slot.
Also going to adding bracing.
UM12 has better low end extension, but start lacking of output at 30hz.
With the um15, at 40 I have 3db more, and by 60 I have 5db.
That’s all projected I guess.
people with more experience than me could tell you more about why um15 are better in my case.
Attachments
I think we have understood your situation quite well. You got a medium size not very resonant room and your better part has agreed to 5 1/2 cubic feet =155 liter. You have unlimited, DSP controlled power (4x3000W peak).
You would prefer a solution that can be improved when funds allow.
You can shop for Dayton Audio products from your location.
One logical answer Is a UM15-22, which will give you a very impressive HT sound, you can only match with commercial products in the 4 digit range. If there are any which allow advanced DSP control around.
Your volume can take one 15" Dayton or two. Using two will give you 3 dB more max. level, and use up 4 times that much amp power. This is, with an iNuke 6000DSP, no real problem. (IMO one amp per driver will give you even better sound, as the iNuke power supply limit its output and Behringer is not really trustworthy with power numbers. You mentioned you have two of them).
So build your 5.5' cabinet in a way that may allow a second driver. If, after trying it single, you decide to really need the extra 3dB, you are not limited.
Of course, then use the benefit of opposing cones!
Please do not care too much about the simulated frequency response. If you use winISD, better do not look like hypnotized at the magnitude graph, but have an eye on max spl and cone excursion. You have to understand that in the end room and DSP give the audible impression.
In most cases, such a high power, long excursion 15" should give you anything you can expect from a high end HT.
Also, keep in mind the limits of your other speakers and the (not to high power) AVR. I expect them to limit your HT experience much more than a single 15" Dayton.
You would prefer a solution that can be improved when funds allow.
You can shop for Dayton Audio products from your location.
One logical answer Is a UM15-22, which will give you a very impressive HT sound, you can only match with commercial products in the 4 digit range. If there are any which allow advanced DSP control around.
Your volume can take one 15" Dayton or two. Using two will give you 3 dB more max. level, and use up 4 times that much amp power. This is, with an iNuke 6000DSP, no real problem. (IMO one amp per driver will give you even better sound, as the iNuke power supply limit its output and Behringer is not really trustworthy with power numbers. You mentioned you have two of them).
So build your 5.5' cabinet in a way that may allow a second driver. If, after trying it single, you decide to really need the extra 3dB, you are not limited.
Of course, then use the benefit of opposing cones!
Please do not care too much about the simulated frequency response. If you use winISD, better do not look like hypnotized at the magnitude graph, but have an eye on max spl and cone excursion. You have to understand that in the end room and DSP give the audible impression.
In most cases, such a high power, long excursion 15" should give you anything you can expect from a high end HT.
Also, keep in mind the limits of your other speakers and the (not to high power) AVR. I expect them to limit your HT experience much more than a single 15" Dayton.
I, currently, am going for the 2: 15in in sealed 2.5 cubic feet.
The box without the slot.
Also going to adding bracing.
UM12 has better low end extension, but start lacking of output at 30hz.
Attachments
Really sums it up pretty well!
I really value the time you guys take to answer.
You said to not pay to much attention to transfer function, because in room response won’t be the same and to look at max spl and cone excursion. Max spl, I get it, it come excursion? What information should I get from this graph? What to look for?
Also, I heard somewhere, and correct me if I’m wrong, but the UM15 would have the same “motor”/ magnet than the um12. Is that concerning?
As discuss with GM, would it be benifical to build 2 box of 2.5-2.75 cubic feet, or 1 of 5-5.5 cubic feet?
Also, what are the preferred connector for such build ? Banana plug? Spade? Speakon?
The table box will sit on steel leg and steel legs will be on a thick carpet, on hard wood floor. Do I need anything between wood box and steel leg? And between steel leg and carpet/floor in order to transfer the least amount of vibration and all?
Thanks again for your time.
Cone excursion
is the way the cone has to travel for a certain spl at a frequency. Linear travel is what shows us the limit.
Mechanically it is half the height of the voice coil minus the magnet gap. With the UM15 this is 19 mm in and 19mm out. The red line at cone excursion. There are other ways to define it, as the magnetic field has no sharp ending point. Some brands would add like 1/4 to that value, making it 23.75mm linear. "Klippel" measurements define it when the driver reaches a certain distortion level and show this to match reality quite well. This is only of interest if the amp has enough power and the frequency is hit. Short bursts, like explosions, do not have problems with 10% THD for example. Music is something else.
If your driver data have been entered correctly for winISD, they should be like 19mm and 800W rms.
If you enter 23mm and 1600W manually at the point -driver-edit-parameter you will have a more realistic prediction for HT use with your amp.
Then go to cone excursion and open "signal". With a single UM15 you will see that about 1250W drive the cone to 23mm. "Maximum power" will show you similar results. This is the safe short time limit.
Please, take all these data with a grain of salt, as the in room result of a real sub working will be quite different. You see what such a sub can do to the air in front of it's cone(s), but not what the air does to your living room. With such a machine, be prepared to fix all kinds of rattling things, sometimes even not so well build dry walls resonate.
These are also the data you should keep in mind when setting the DSP. All this will become quite easy to understand when you have the sub in your room, a microphone connected and the DSP menu open. The iNuke has a very clever, level and frequency dependent limiter you can design around max cone travel. So if for some reason you increase volume over the safe level, the lowest frequncy will simply not get louder than the set limit.
So 20 Hz will stay at 109dB, while 30 Hz can still hit 116dB. In theorie, the in room level will sure be higher. As you can pass word lock the DSP settings, you can make your sub "teen party proof" that way.
"Motor"
Do not worry about the "motor" of a driver. It is the cone area that matters. There is nothing wrong with the UM15-22. A very good driver, at a very acceptable price point = you can get the same or much worse drivers for much more $. Really great value for money.
You seem to get a lot information from quite opposing sources. Value may vary. Not everything is true, own experience with serious background.
Volume of cabinet.
If possible, I divide such a volume diagonally, as it reduces resonance inside the cabinet. Parallel walls are not the best in this sense.
You want to start with a single driver, in this case I would leave an opening of about cone area in the divider. Maybe close it with a prematched panel, when the second driver is installed. No need to go take very strong material, as the pressure on both sides will be near to identical. Same with the opening for the second chassis, screw in a piece of wood temporarily. This cover has to be braced from the inside, if becomes permanent.
The question single or divided volume for identical drivers is simple to answer. To prevent problems from tolerances within two identical chassis, separate is better, also, the smaller the volume, the higher the resonances inside are.
Last, a sub woofer usually works fine without any material inside. If you ask me, I will in almost any case fill it with some material like rock wool. First, it increases the virtual volume, leading to a lower f3, second, any higher frequency is damped. You can argue there are none, as you have a steep x-over. As there are no cons with stuffing it, I simply go for the extra 15$ as it really doesn't break the bank on such a project.
PS have you ever calculated what undistorted level your main and center speaker, connected to your AVR, can deliver? I think even a single UM15-22 will overpower them with ease.
is the way the cone has to travel for a certain spl at a frequency. Linear travel is what shows us the limit.
Mechanically it is half the height of the voice coil minus the magnet gap. With the UM15 this is 19 mm in and 19mm out. The red line at cone excursion. There are other ways to define it, as the magnetic field has no sharp ending point. Some brands would add like 1/4 to that value, making it 23.75mm linear. "Klippel" measurements define it when the driver reaches a certain distortion level and show this to match reality quite well. This is only of interest if the amp has enough power and the frequency is hit. Short bursts, like explosions, do not have problems with 10% THD for example. Music is something else.
If your driver data have been entered correctly for winISD, they should be like 19mm and 800W rms.
If you enter 23mm and 1600W manually at the point -driver-edit-parameter you will have a more realistic prediction for HT use with your amp.
Then go to cone excursion and open "signal". With a single UM15 you will see that about 1250W drive the cone to 23mm. "Maximum power" will show you similar results. This is the safe short time limit.
Please, take all these data with a grain of salt, as the in room result of a real sub working will be quite different. You see what such a sub can do to the air in front of it's cone(s), but not what the air does to your living room. With such a machine, be prepared to fix all kinds of rattling things, sometimes even not so well build dry walls resonate.
These are also the data you should keep in mind when setting the DSP. All this will become quite easy to understand when you have the sub in your room, a microphone connected and the DSP menu open. The iNuke has a very clever, level and frequency dependent limiter you can design around max cone travel. So if for some reason you increase volume over the safe level, the lowest frequncy will simply not get louder than the set limit.
So 20 Hz will stay at 109dB, while 30 Hz can still hit 116dB. In theorie, the in room level will sure be higher. As you can pass word lock the DSP settings, you can make your sub "teen party proof" that way.
"Motor"
Do not worry about the "motor" of a driver. It is the cone area that matters. There is nothing wrong with the UM15-22. A very good driver, at a very acceptable price point = you can get the same or much worse drivers for much more $. Really great value for money.
You seem to get a lot information from quite opposing sources. Value may vary. Not everything is true, own experience with serious background.
Volume of cabinet.
If possible, I divide such a volume diagonally, as it reduces resonance inside the cabinet. Parallel walls are not the best in this sense.
You want to start with a single driver, in this case I would leave an opening of about cone area in the divider. Maybe close it with a prematched panel, when the second driver is installed. No need to go take very strong material, as the pressure on both sides will be near to identical. Same with the opening for the second chassis, screw in a piece of wood temporarily. This cover has to be braced from the inside, if becomes permanent.
The question single or divided volume for identical drivers is simple to answer. To prevent problems from tolerances within two identical chassis, separate is better, also, the smaller the volume, the higher the resonances inside are.
Last, a sub woofer usually works fine without any material inside. If you ask me, I will in almost any case fill it with some material like rock wool. First, it increases the virtual volume, leading to a lower f3, second, any higher frequency is damped. You can argue there are none, as you have a steep x-over. As there are no cons with stuffing it, I simply go for the extra 15$ as it really doesn't break the bank on such a project.
PS have you ever calculated what undistorted level your main and center speaker, connected to your AVR, can deliver? I think even a single UM15-22 will overpower them with ease.
Last edited:
Thanks for clarifying this.
As for dividing diagonally, does It absolutely need to be from corner to corner?
I didn’t calculate undistorted level from front stage speaker.
How would I do this? Same way I did with subwoofer measurements?
Set the umik-1, and make some sweep and reading from 50-20khz ?!
If you build a divider, just do not make it in a 90° angle, but something from 25-45°. That way the sound does not get reflected as a straight wave, which fits exactly one wavelength, leading to a strong resonance, By the way, inside bracing has some sound wave diffusing properties too.
This is something I do if it is possible, just to make a good design better. It is no "must do", as the usual sub woofer theoretically does not emit high frequency which will fit between the walls. Anyway, it can not do any harm, is usually no extra cost and can reduce harmonics.
With DIYS you can do what the industry ignores, mostly to cut cost's at any corner.
Maximum level from your speakers largely depends on the low cut they get. Usually 80 Hz, you may lift that to 100 Hz without any negative effect.
Calculate the level by the sensitivity and the max power they are build for. Like 86dB 1 watt/ 1 meter equals 96dB with 10W and 106dB driven by 100W.
If you cut them at 100Hz with 12 dB/Oct or steeper, in practice you should be able to hear very loud.
Anyway, the usual AVR will not deliver much watt if you use all channels. The impressive 120W per channel may be reduced to 5x 40W, even less if you have 8 Ohm speaker. You sure do not want to drive your main, center and surround speaker into clipping! A weak AVR will reduce the headroom, which may make the amp sound stressed.
If we talk stereo HIFI, a sub woofer reduces load on main speaker and main amp, which leads to much better sound. With the average AVR this relieve is already included in the design, as it has no power hungry sub frequency amp stage build in.
I was quite surprised when I replaced my Onkyo TX-NR818 AVR with a Denon X-4100W.
The Onkyo put 48.5 lb on the scale, the Denon is a 28 lb featherweight in comparison.
I'm under the impression the Onkyo had more “slam” with the same speakers.
I have planed to beef up the Denon with some external amps anyway...
This is something I do if it is possible, just to make a good design better. It is no "must do", as the usual sub woofer theoretically does not emit high frequency which will fit between the walls. Anyway, it can not do any harm, is usually no extra cost and can reduce harmonics.
With DIYS you can do what the industry ignores, mostly to cut cost's at any corner.
Maximum level from your speakers largely depends on the low cut they get. Usually 80 Hz, you may lift that to 100 Hz without any negative effect.
Calculate the level by the sensitivity and the max power they are build for. Like 86dB 1 watt/ 1 meter equals 96dB with 10W and 106dB driven by 100W.
If you cut them at 100Hz with 12 dB/Oct or steeper, in practice you should be able to hear very loud.
Anyway, the usual AVR will not deliver much watt if you use all channels. The impressive 120W per channel may be reduced to 5x 40W, even less if you have 8 Ohm speaker. You sure do not want to drive your main, center and surround speaker into clipping! A weak AVR will reduce the headroom, which may make the amp sound stressed.
If we talk stereo HIFI, a sub woofer reduces load on main speaker and main amp, which leads to much better sound. With the average AVR this relieve is already included in the design, as it has no power hungry sub frequency amp stage build in.
I was quite surprised when I replaced my Onkyo TX-NR818 AVR with a Denon X-4100W.
The Onkyo put 48.5 lb on the scale, the Denon is a 28 lb featherweight in comparison.
I'm under the impression the Onkyo had more “slam” with the same speakers.
I have planed to beef up the Denon with some external amps anyway...
so, that was the math behind it ? I should crossover my Criton at 100hz ? No sure what 12db/oct means.
thought it was something with REW and measurement hahah
See,
low frequency needs most of an amps power, The higher you set the low cut, the more power reserve your AVR has to reproduce the rest of the spectrum.
If you cross too high, the sub woofer may get audible. So there is a sweet spot where we get the best match.
Now, the order of the cut (may it be high or low) tells you how much sub and mid play together.
First order is 6dB/Oct, second 12 dB, third 18 dB and so on.
Maybe go to the "Filters" section of winISD and play around to see how this works.
Ah! An "octave" is 1/2 or two times a frequency. So one octave down from 80 Hz is 40 Hz, up 160Hz.
low frequency needs most of an amps power, The higher you set the low cut, the more power reserve your AVR has to reproduce the rest of the spectrum.
If you cross too high, the sub woofer may get audible. So there is a sweet spot where we get the best match.
Now, the order of the cut (may it be high or low) tells you how much sub and mid play together.
First order is 6dB/Oct, second 12 dB, third 18 dB and so on.
Maybe go to the "Filters" section of winISD and play around to see how this works.
Ah! An "octave" is 1/2 or two times a frequency. So one octave down from 80 Hz is 40 Hz, up 160Hz.
Sorry, dont know how to ''tag'' someone on here.
what do we think of the Dayton MX-15, its 310$ cad. So i could get both for the dual opposed driver right away. I get a Qtc of 0.706 in a 2.6cubicfeet box. F3 is a bit high tho, but not factoring in the room gain, at 39hz. Cone excursion isnt going over its limit until 20hz. Group delay is 8ms at 10hz, at 40hz its 9ms.
Those are stout for the cost. I would feel that's a solid driver to use. You can likely boost the bottom end to regain extension.
‘Bang for the buck’ win!
Inductance is fugly .. gets kinda weird up top…. Dunno when that matters if XO @ 65 though
Inductance is fugly .. gets kinda weird up top…. Dunno when that matters if XO @ 65 though
Right?!
not the best driver out there, but for a start, its something.
Didn’t think of where I would xo this driver. Thought of going 80 like the other one. Probably better this than my criton to play to 65
