| 5-XLS's, 4-PR's, Adcom Mono Blocks and 1" MDF - Click HERE for Original Thread |
| DaHos |
Gee, now what can I do with all this stuff? The subs are 10" (home version) the PR's are 265g, and the Amps have LOTS of power.
I'm Looking for a well blended design for Music, HT and DVD/SCAD audio use. The only x-over/EQ I currently have is the low pass of my Denon 3803. I would be open for a over the counter active unit as my DIY skills in this area are none.
The mains are the Proac clones and the surrounds are a SS 8545/9500 combo.
I have also concidered selling the Adcoms and using the Adire ADA600 plate amps as they seem to be pritty nice.
The room is aprox 4m x 8m.
So any ideas, I am open to anything as no WAF is required :D ???????????
Thanks Much................ |
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| iz |
put the xls's in sealed Vas enclosures..... if it's the 10" XLS the enclosures should be 89ltr. pr. driver.... the good thing is that they have a gentle rolloff so you can place them near walls/corners..... like in the real world...
i guess that by PR's you meen passive radiators..... i don't like PR's so i would suggest not using them.... they are good for reducing the size of enclosures.... but not good for the sound of the sub...
build an active 24dB/oct crossover acoording to this http://sound.westhost.com/project09.htm and...... happy camping!!
did that myself for a friend.... never heard anything like it..... and i've heard quite alot i the past 20 years.... |
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| simon5 |
Well you could go for max SPL or a smaller design.
I would use the PRs to tune very low.
You could do two small subwoofers with an isobaric pair in each one, or a big box with 5 drivers and 4 PRs hehehe!
iz, did you hear a sub tuned under 20 Hz? Maybe not, maybe that's why you hate PRs so much.
Do you have the T/S parameters of your PRs? |
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| iz |
"iz, did you hear a sub tuned under 20 Hz? Maybe not, maybe that's why you hate PRs so much."
i'm not sure what you mean...
yes i've heard sub with useable output below 20Hz... the 2001 overture is a must in sub tests... :) ....
the PR equipped speakers i've heard have a problem "stopping" after transients... almost like a bit of reverb... but i'm pretty openminded so the day i hear a really "tight" system i will (maybe) change my mind...
i think that PR's and ports are just there to ensure the WAF rather than the highest fidelity... |
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| Raoul |
| Hi iz. I think what simon5 is trying to accomplish by tuning under 20Hz is tucking the group delay, etc. below audible limits. The idea, then, is less about getting a response below 20Hz, and more about getting clean, tight output above 20Hz. |
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| DaHos |
| quote: | Originally posted by Raoul
The idea, then, is less about getting a response below 20Hz, and more about getting clean, tight output above 20Hz. |
This sounds interesting, Keep it up guys..............
PS: 89ltr sealed, Thats one I didn't think of.........
:confused: :confused: :confused: |
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| simon5 |
| Do you have the T/S parameters of your PRs? |
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| DaHos |
| quote: | Originally posted by simon5
Do you have the T/S parameters of your PRs? |
No, I have been unable to define/confirm the following:
Fsp - PR free air resonance frequency =?
Mmp - Mechanical mass of PR diaphragm=265g
Qms - Q of driver at Fsp considering mechanical losses only=?
Sdp - Effective area of PR diaphragm=?
Xpmax - Peak linear PR excursion =?
I checked the D-S-T website with no luck.....
I am still searching and reading all I can to try to get a grasp on all this.
The designs I have seen all seem to use 1 driver or 1 driver with 1 or 2 PR's in a vol of 20-35 ltr.
So I can follow the norm or try to do somthing a little different....with the help from whom ever can help.
I am going to slap together a 28 ltr test box for the 5th sub just to get a feel for whats going on...
I thank you all again... D |
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| simon5 |
Found it for you, so it'll be easier for us now...
Peerless XLS 10" Passive Radiator (830481)
Parameter Value
Fs 13.7 Hz
Qms 11.4
Vas 80 l
Rms 2 Kg/s
Mms 265g
Cms 0.508 mm/N
Sd 333 cm2
xmax 22 mm |
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| simon5 |
| Do you know if you can add mass to the passive radiators? If yes, how much? |
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| DaHos |
Yes the end is threaded, Id guess no more than ~300g
PS: Is unibox a suitable modeling program, as I see It has design provisions for the PR's. |
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| simon5 |
| Yes, Unibox or WinISD are both good modeling programs. |
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| simon5 |
You could do 4 XLS with 4 PRs with 300g added per PR in a 110 liters box with 325W RMS.
It seems hard to go low with these drivers hehe, 4 drivers and 4 PRs to achieve the low end of a single shiva. The midbass will be alot louder hehe. |
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| simon5 |
My final idea is to forget the PRs.
Go vented with two 4" diameter pipes 28 inches long.
Put 5 XLS in there, with a full 1600W RMS.
180 liters box, tuned to 18.52 Hz.
127 dB at 20 Hz in room. No vent noise problems, because at 117 dB at 20 Hz in room you're below 5% speed of sound (175W RMS), at 123 dB at 20 Hz in room (700W RMS) you're still below 10% speed of sound. If you go full output at 127 dB (1600W RMS), I guess you can't hear the vent noise even if it's higher than 10%.
I would design it like this :
o...o
v.o.v
o...o
v = port and o = XLS
Nice front panel hehe, a big X of woofers with two vents! |
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| Dave Jones |
| quote: | Originally posted by iz
put the xls's in sealed Vas enclosures..... if it's the 10" XLS the enclosures should be 89ltr. pr. driver.... |
That's about a three times bigger box than recommended by Peerless. Have you modeled that alignment and looked at the FR response curve?
I made a sub using the same driver but with the 400 gram PR. The box is 26 liters after you subtract for speakers, shelf braces, etc. I used 3dB boost at 21Hz on the plate amp. The attached plot shows how it models with the boost included in the calculation. In the room where I use it, it's pretty darned flat to 20Hz.
I am completely satisfied with it.
With the 265 gram PR in the same size box with the same EQ, the modeled response is very flat to about 28 Hz, then falls of precipitously below that. I thought the gentler rolloff with the heavier PR would match up better with room lift. That's why I went with the 400 gram version.
DaHos, If you have an alignment in mind, I could model it. |
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| Dave Jones |
| quote: | Originally posted by simon5
My final idea is to forget the PRs. |
Why? The driver is designed to be used with the matching PR's. |
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| DaHos |
Dave,
Well Im sitting here messing with unibox and I am getting some interesting stuff. The design you have made is similar to what I have in mind but would like to use 2 Drivers per unit. As these will be used as bass units for a 2 way set up. I have to agree that the mid bass (30-150 is flat @ 112 db) I may just have to add a 15" to the mix for HT use. My test cab is 10"x24"x14" so about 50 ltr. max.
Gonna keep at it...... |
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| Dave Jones |
| quote: | Originally posted by DaHos
Dave,
Well Im sitting here messing with unibox and I am getting some interesting stuff. The design you have made is similar to what I have in mind but would like to use 2 Drivers per unit. As these will be used as bass units for a 2 way set up. I have to agree that the mid bass (30-150 is flat @ 112 db) I may just have to add a 15" to the mix for HT use. My test cab is 10"x24"x14" so about 50 ltr. max.
Gonna keep at it...... |
Try this: Put two drivers and two PR's in the 50ltr box. Add weight to the PR's to bring them up to about 400 grams. Use 3dB boost at 20 Hz. |
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| Dave Jones |
| quote: | Originally posted by DaHos
Dave,
My test cab is 10"x24"x14" so about 50 ltr. max.
Gonna keep at it...... |
Inside dimensions, right? |
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| DaHos |
Yes, they are inside. 10 wide, 24 tall and 14 deep, I figured with bracing etc should put me about 45 ltrs.
This is with 400g total for the PR. |
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| DaHos |
| But the PR gives up at about 25hz. |
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| DaHos |
Which would be better 1 lg volume or 2 sm volumes in one....?
The driver and PR will be on the same axis, driver ft and PR rear.
It looks almost the same either way. Bumping up the mass to 600 will get me lower and allow for more extension, but thats alot of weight on the 265g units I have to work with....and yes I do agree that any of these designs will need a little kick in the 20 hz range.
What could I expect of room gain to aid in the dip? |
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| DaHos |
| I luv MDF dust........ |
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| simon5 |
Why you don't like my ideas?
They are good, check the frequency response in WinISD.
The PRs are too light to be used with this woofer it seems to get any reasonable performance at 20 Hz.
If it was the 400g version, it would probably be different.
You lose more than 10 dB of efficiency by using these PRs... that's enormous!
Here are both of my ideas : |
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| DaHos |
Simon, I do thank you for your input.
Your design was similar to a foot stool/coffee table I had looked into as the size of the cab would work.
I figured the sub cabs I made should work "ok" and could be moved around as needed or gutted for another project.
I am still unsure if I should open the top and bottom chambers or keep the 2 smaller ones as the other than the "db" the graphs are very close. Running 4 of then in 1 room should give plenty of good ole SPL.....
Any advice on this would be helpful.
Funny thing is I ended up making a typical XLS sub after all........ :rolleyes: |
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| simon5 |
| Well, more headroom is not bad, I would get as much space as I can. |
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