It's been a long journey up to here lol.
So originally i built a full marty thinking if i do it right, do it once. It only fit in the corner of the room vertically. But there seems to be a lot of nulls, and upon
doing more reading, a general recommendation is two subs to even things out. So I was thinking either two full martys, which i can lie on the side and put along the front wall, or two 4cf sealed subs. Then i read a bit more about the spec changes on the UM18-22 and people were not recommending them anymore.
So thoroughly confused, im now at this point.
To recap, I've build some substantial 3 way floor standers, high end, with a sealed 12" bass driver, which i should be able to EQ pretty flat to where i crossover to the subs. Using a Hypex FA253 amp/dsp.
They are currently getting painted, so i cant do any work with them for a week or two, so working on the sub plans in the mean time
So originally i built a full marty thinking if i do it right, do it once. It only fit in the corner of the room vertically. But there seems to be a lot of nulls, and upon
doing more reading, a general recommendation is two subs to even things out. So I was thinking either two full martys, which i can lie on the side and put along the front wall, or two 4cf sealed subs. Then i read a bit more about the spec changes on the UM18-22 and people were not recommending them anymore.
So thoroughly confused, im now at this point.
To recap, I've build some substantial 3 way floor standers, high end, with a sealed 12" bass driver, which i should be able to EQ pretty flat to where i crossover to the subs. Using a Hypex FA253 amp/dsp.
They are currently getting painted, so i cant do any work with them for a week or two, so working on the sub plans in the mean time
Even with sub optimal specs, the UM18 can still move quite a bit of air. You have plenty of power available and a DSP... Size the sealed box to reach xmax on your available amp power and Linkwitz transform the result to your desired Qtc as a starting point, and then add EQ to taste for your room's response. If your room is huge or you listen at very high levels, you can always add and integrate more sealed subs.
As you have a full Marty and a small cube, you may try the UM18-22 in both. My prediction, you will like it better in the huge box.
PS with 430 liter volume, you get a Qts of 0.7 which is about the best you can do with the UM18-22, while the 113 liter cabinet results in 1.0
That is only 0.3 on paper, but you see the difference in volume. You can DSP the 0.7 down to 20 Hz. The second full Marty will give 6dB more,
That is only 0.3 on paper, but you see the difference in volume. You can DSP the 0.7 down to 20 Hz. The second full Marty will give 6dB more,
So I just done some experimenting.
I Set the mic up in the MLP and done a sweep of the sealed UM18-22 in the 4cf box.
Then i put the driver back in the full marty cabinet and layed it on its side to sit in the same spot roughly.
Graph attached. No eq or anything.
Blue is sealed, Red is ported
I Set the mic up in the MLP and done a sweep of the sealed UM18-22 in the 4cf box.
Then i put the driver back in the full marty cabinet and layed it on its side to sit in the same spot roughly.
Graph attached. No eq or anything.
Blue is sealed, Red is ported
Attachments
I see your not keen on these drivers and you have good knowledge also. I saw a post where you stated Qtc of 0.7 to be bad.
Its unfortunate that I have four drivers all at .7
2x um18 133L boxes sealed 4 ohm
2x sb rosso sw21/800 160L boxes sealed 8 ohm
will these drivers be cleaner in huge sealed boxes. they sound very restricted
I have had the dayton in a ported arrangement and i didnt like it as you also stated. I want it to be smooth with nice transition from 50hz down and at the moment its all smeared. does that make sence? I have dsp and the amps are crown xls 1502 x4
I think my mistake is not using the power handling chart to gauge the boxes as the daton can take power for ever in the 113L box..
Im not bothered about box size.
Can I do anything with these drivers??? Or should i cut my loss
If i was to my loss what are best drives for sealed boxes for low end extension?
I you could advice it would much appriciated. steve
I want to try and stay sealed. How about huge sealed boxes.. I will add more subs if i need more.. bigger boxes will lower the power handling also and that may come in handy.. I do agree with you though.. too small
I couldn't agree more Baldin but i got confused by a post saying "you can eq the qtc down to 0.8", my eq looks like the red line. 4 subs playing at low volume to get real low end extension to 20hz and below. Is this changing the QTC of the box??? If so can I measure the phenomenon 🙂sb rosso sw21/800 160L is just way to little volume I think ..
Vented in 600 liter, tuned to 25 Hz and at 500W will give you 119 dB
At 160 L closed you have Qtc = 0.9, and at 500 W you have some 105 dB at 25 Hz (but still a lot of bass 😉 )
Your red line is around a -12dB roll off per decade (nor would it stop at 20Hz without a HP filter), it doesn't specifically change the value of Qtc, the closed box Q of the speaker/box system at Fc, the closed box resonance frequency.
Fc is always higher than Fs, the free air resonance.
You can measure the near field frequency response of your sub, and equalize it to match the total system Q you would like, within the linear response of the driver.
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Fairly simple with sealed boxes.
Ideal Qtc is the same old .5 to .7
.7 being more common.
Problem with a high Qts woofer is
box size will be rather large to obtain even .7 Qtc
So tradeoff usually climbs to .8 to .9
Which would still be a large box.
Then you stuff the box to royal heck with
absorption material.
And all done.
No need for wild guessing
You enter the driver parameters into sim.
Then calculate the needed box volume.
Roll off is what it is. Size is what it is.
And you just roll up the EQ for listening.
Depending on listening levels or song.
Those settings change like any other normal day.
In advanced settings in WinIsd
leakage and absorption are set to
somewhat high values.
Leakage ( Ql) is set to 10
8 being more realistic sealed.
Absorption ( Qa) being set to 100
= no absorption.
You can change it to around 80
for lined or 30 to 60 for being stuffed
to royal heck.
If the box is to small you get a bump in the response.
This will make some songs or notes " Bloom"
or sound over EQ'ed.
People forget full space losses so a slight bump
Usually being ideal and actually requires less EQ
Ideal Qtc is the same old .5 to .7
.7 being more common.
Problem with a high Qts woofer is
box size will be rather large to obtain even .7 Qtc
So tradeoff usually climbs to .8 to .9
Which would still be a large box.
Then you stuff the box to royal heck with
absorption material.
And all done.
No need for wild guessing
You enter the driver parameters into sim.
Then calculate the needed box volume.
Roll off is what it is. Size is what it is.
And you just roll up the EQ for listening.
Depending on listening levels or song.
Those settings change like any other normal day.
In advanced settings in WinIsd
leakage and absorption are set to
somewhat high values.
Leakage ( Ql) is set to 10
8 being more realistic sealed.
Absorption ( Qa) being set to 100
= no absorption.
You can change it to around 80
for lined or 30 to 60 for being stuffed
to royal heck.
If the box is to small you get a bump in the response.
This will make some songs or notes " Bloom"
or sound over EQ'ed.
People forget full space losses so a slight bump
Usually being ideal and actually requires less EQ