Hi! - if anyone can offer their twopenneth on my SS 12'' sub (discovery) that would be great. Given there is not too much specific on this driver I feel the post might be useful too.
I made this a year or so ago - seems to be going ok though i wonder whether i have got the most out of it.
after conflicting info and suggestions, for max depth (don't require much sound volume) i went for the biggest reccomendation for sealed cab size @ 84ltr/3cuft i did this on the basis it can always be cut down in size or reduced internally.
i am interested on opinions re;
1; whether going the passive driver route at madisounds reccomended 2.5cuft would be superior
2; ditto, madisounds reccomended 2.5cuft vented ScanSpeak Discovery 30W/4558T 12" Subwoofer
3; comments about current enclosure volume
requirements are; to max out on depth - max volume not required, its about subtle extension 32ft organ pipes/orchestral bass drum/strengthening of really low stuff.
N.B. I have looked at various calculators and modeling things, though end up going round in circles somewhat...
anyway - any input gratefully recieved, and hopefully a few more ideas re this driver on the net.
other info; down firing, 25mm mdf with ply skin, oak top (from skip!) contruction (internal) similar to; http://www.humblehomemadehifi.com/library/Humble Homemade Hifi_CAD_Concert_Sub_32W.pdf
it is driven passively by a ucd400 into passive xover, and i think that side of things is working out - it doesnt intrude on mains and seems to kick in about right (40k- the mains are 8'')
driver; Scanspeak 30W/4558T00 SubWoofer - Discovery Range
I made this a year or so ago - seems to be going ok though i wonder whether i have got the most out of it.
after conflicting info and suggestions, for max depth (don't require much sound volume) i went for the biggest reccomendation for sealed cab size @ 84ltr/3cuft i did this on the basis it can always be cut down in size or reduced internally.
i am interested on opinions re;
1; whether going the passive driver route at madisounds reccomended 2.5cuft would be superior
2; ditto, madisounds reccomended 2.5cuft vented ScanSpeak Discovery 30W/4558T 12" Subwoofer
3; comments about current enclosure volume
requirements are; to max out on depth - max volume not required, its about subtle extension 32ft organ pipes/orchestral bass drum/strengthening of really low stuff.
N.B. I have looked at various calculators and modeling things, though end up going round in circles somewhat...
anyway - any input gratefully recieved, and hopefully a few more ideas re this driver on the net.
other info; down firing, 25mm mdf with ply skin, oak top (from skip!) contruction (internal) similar to; http://www.humblehomemadehifi.com/library/Humble Homemade Hifi_CAD_Concert_Sub_32W.pdf
it is driven passively by a ucd400 into passive xover, and i think that side of things is working out - it doesnt intrude on mains and seems to kick in about right (40k- the mains are 8'')
driver; Scanspeak 30W/4558T00 SubWoofer - Discovery Range
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Wait, you're using a passive crossover on a subwoofer?!
I'd bypass that, for a start, and use one at line-level.
Apart from that, what is it you're finding lacking about the current cabinet? A decent 12" in a sealed box ought to do pretty well in the average UK-sized living room.
Have you done any measurements?
Chris
I'd bypass that, for a start, and use one at line-level.
Apart from that, what is it you're finding lacking about the current cabinet? A decent 12" in a sealed box ought to do pretty well in the average UK-sized living room.
Have you done any measurements?
Chris
thanks for your reply chris
the cab seems to work quite well - principally i'm just checking out folks thoughts on whether the size is optimum (being larger than most reccomendations), and perhaps any thought whether the other configs would represent an improvement with regard my requirments.
the xover btw is a speaker xover not line level. i did this as i felt it avoided an extra line stage of potentially cheap electronics, making the system simpler and more direct - if less flexible. a bit different i admit - though the thought was this is the same methodogy that the mains are running off anyway..
i don't have experinece or equipment for measuring
the cab seems to work quite well - principally i'm just checking out folks thoughts on whether the size is optimum (being larger than most reccomendations), and perhaps any thought whether the other configs would represent an improvement with regard my requirments.
the xover btw is a speaker xover not line level. i did this as i felt it avoided an extra line stage of potentially cheap electronics, making the system simpler and more direct - if less flexible. a bit different i admit - though the thought was this is the same methodogy that the mains are running off anyway..
i don't have experinece or equipment for measuring
Even using bit ferrite cores (which present their own problems), inductors for crossover <100Hz will add non-trivial DC resistance.
If you're happy, then fair enough. I'd want a separate amp for the sub, though. If you're near Sheffield, I have some amps I could bring over so you can see what I'm on about.
Chris
If you're happy, then fair enough. I'd want a separate amp for the sub, though. If you're near Sheffield, I have some amps I could bring over so you can see what I'm on about.
Chris
thanks for your thoughts and the offer chris which i really appreciate, though i am way down south nr salisbury! (i've looked at your impressive site btw - did you make the pa speakers?)
the ucd is a seperate amp for sub, the mains are nc400x2 (i haven't made everything as clear as i thought).
i do have a cheapo chinese active sub equalizer to experiment with (link below) (and decentish psu) which i presumed would be on the front end of most plate amps, and looked quite horrible, and somehow i thought it sounded a bit 'fake' - hence going inductor route, which seemed a bit 'purer'.
what were you going to suggest? (i don't think i could justify a new amp)
DC 12V-24V Low-pass Filter NE5532 Subwoofer 2.1CH Pre-Amplifier Preamp Board UK | eBay
the ucd is a seperate amp for sub, the mains are nc400x2 (i haven't made everything as clear as i thought).
i do have a cheapo chinese active sub equalizer to experiment with (link below) (and decentish psu) which i presumed would be on the front end of most plate amps, and looked quite horrible, and somehow i thought it sounded a bit 'fake' - hence going inductor route, which seemed a bit 'purer'.
what were you going to suggest? (i don't think i could justify a new amp)
DC 12V-24V Low-pass Filter NE5532 Subwoofer 2.1CH Pre-Amplifier Preamp Board UK | eBay
Yep, the main PA speakers are designed and built in-house (although the subs were a product of this forum!). Thanks for taking the time to have a look.
Having a separate amp for the sub is the way to do it. If it was mine, I'd be looking for DSP or enough analogue EQ to flatten out the worst of the room effects at the listening position.
Chris
Having a separate amp for the sub is the way to do it. If it was mine, I'd be looking for DSP or enough analogue EQ to flatten out the worst of the room effects at the listening position.
Chris
OK - i think you've confirmed the 'area' - if there is any particular product you can reccomend for me to consider that would be cool. it needs to be a line in, line out device. I don't mind eq'ing by ear - i guess i can experiment first, (have logic pro) suspect a dual band parametric might work well.
Two options for budget-but-works:
Digital: Behringer DCX2496
Analogue: Behringer CX2310 plus whatever EQ you can find.
Since you've got Logic Pro, do you have a separate mix output you could use? There's a lot of DSP there.
Chris
Digital: Behringer DCX2496
Analogue: Behringer CX2310 plus whatever EQ you can find.
Since you've got Logic Pro, do you have a separate mix output you could use? There's a lot of DSP there.
Chris
thanks for your help chris - i will think on these things! i have a decent interface with the logic and of course for clues could use the analyser - i am really a tinkerer in this diy field, (am really a musician - hence logic) so thank you for your replies.
That driver is more suited to a vented enclosure i think. with a QTS of 0.32 it's not fit for sealed. Sealed need more a qts above 0.4 to work well. With a sealed enclosure it will never go very low. If you make a vented enclosure it will be much larger (especially if you want it to go low).
Thanks for your reply.
OK - interesting, a pity SS give so little in the way of suggestions. I have seen it suggested as workable as sealed though must take your point it is probably better vented.
I actually have 3.2cuft/91 L to play with (can reduce internal area easy) and madisounds reccomendation for both adding the SS passive radiator or a vent is 2.5cuft, a reduction of what i have currently.
Have you a view on a vent vs adding the passive?
If you could suggest a vent size to try using the current 3.2cuft that would be epic (i've done the rounds with calculators though seem to do round in circles)
OK - interesting, a pity SS give so little in the way of suggestions. I have seen it suggested as workable as sealed though must take your point it is probably better vented.
I actually have 3.2cuft/91 L to play with (can reduce internal area easy) and madisounds reccomendation for both adding the SS passive radiator or a vent is 2.5cuft, a reduction of what i have currently.
Have you a view on a vent vs adding the passive?
If you could suggest a vent size to try using the current 3.2cuft that would be epic (i've done the rounds with calculators though seem to do round in circles)
a 5cm diameter vent of 12cm (sorry, i live in the metric world) should do the job in a 90L (+/- 3.2Cu) enclosure says winisd in a quick sim. The F3 is then 23.5Hz and the F10 of 16.69Hz.
freeware software used is this: WinISD - Linearteam and specs are from the specsheet of Scanspeak. The sim file is attached
freeware software used is this: WinISD - Linearteam and specs are from the specsheet of Scanspeak. The sim file is attached
Hi
I would suggest the passive radiator.
Try it in the cab with the size it has now. You can always put someting in the cab to reduce the volume if that should be better.
It seems that you have a dedicated UcD amp for the woofer. I would suggest to buy a MiniDSP.
The MiniDSP can do the crossover, highpassfilter to protect the woofer and the room equalisation
best regards
uwe
I would suggest the passive radiator.
Try it in the cab with the size it has now. You can always put someting in the cab to reduce the volume if that should be better.
It seems that you have a dedicated UcD amp for the woofer. I would suggest to buy a MiniDSP.
The MiniDSP can do the crossover, highpassfilter to protect the woofer and the room equalisation
best regards
uwe
I disagree, as a passive radiator has a resonance peak at the fs, and then a port is a better solution for good sound. And a dsp or analog crossover won't change that as the passive radiator is not connected to that system.
But i know opions vary on this subject...
A 5cm port won't hold up to a 12" long-throw driver.
For this sort of driver, passive radiators are a good option (it's difficult to fit a large port in a small box, as would be required for a ported system). However, I have found that sealed boxes tend to match up well with a typical room gain curve. When it comes to acoustically small rooms, I find that a flat free-field response (ie, what WinISD simulates) is not desirable, so I tend to aim for something with a gentle rolloff.
If you need to get more output from the driver, ported or PR would be a good way to do it. If you're never close to the limits, I'd still argue that sealed boxes would be superior.
Chris
For this sort of driver, passive radiators are a good option (it's difficult to fit a large port in a small box, as would be required for a ported system). However, I have found that sealed boxes tend to match up well with a typical room gain curve. When it comes to acoustically small rooms, I find that a flat free-field response (ie, what WinISD simulates) is not desirable, so I tend to aim for something with a gentle rolloff.
If you need to get more output from the driver, ported or PR would be a good way to do it. If you're never close to the limits, I'd still argue that sealed boxes would be superior.
Chris
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Hi again
The passive radiator has more options than a port. and no port chuffing at high excursions of the membrane.
If you buy a MiniDSP you can easy try to implement it as a closed box before you even try the passive radiator version.
I agree with Chris that a closed box close to the wall or even a corner usually will sound better / more accurate than basreflex.
The passive radiator has more options than a port. and no port chuffing at high excursions of the membrane.
If you buy a MiniDSP you can easy try to implement it as a closed box before you even try the passive radiator version.
I agree with Chris that a closed box close to the wall or even a corner usually will sound better / more accurate than basreflex.
thank you all so much for this info - i am certainly tending toward the dsp idea regardless - any reccomendations? is the link below the sort of thing? (i need analouge in-out) i would use better psu also.
I suspect dsp will make a radical improvment.
i guess from there i could try the vent easiliy at very low cost, and could plug it and re-veneer the end if nec. thank you for calc wax - we british have cm on one side and inches the other side of our rulers!!
reagarding the resonance of passive - it is 11hz and possibly out of harms way (with high pass on dsp)?
https://www.amazon.co.uk/Dayton-Aud...ocphy=1007144&hvtargid=pla-590974824170&psc=1
I suspect dsp will make a radical improvment.
i guess from there i could try the vent easiliy at very low cost, and could plug it and re-veneer the end if nec. thank you for calc wax - we british have cm on one side and inches the other side of our rulers!!
reagarding the resonance of passive - it is 11hz and possibly out of harms way (with high pass on dsp)?
https://www.amazon.co.uk/Dayton-Aud...ocphy=1007144&hvtargid=pla-590974824170&psc=1
I'd see what the 2nd hand price of a DCX2496 is. Reason being that you can sell it on and recoup the investment, pretty much entirely.
The PR resonance will change once it's loaded into the cab. The best way to determine tuning is with impedance sweeps.
Chris
The PR resonance will change once it's loaded into the cab. The best way to determine tuning is with impedance sweeps.
Chris
I have just remembered I have one of these somewhere in the loft! - will give it a try
Digitech Studio Quad | eBay
Digitech Studio Quad | eBay
Thanks for your suggestions - I have (finally) acted on all the suggestions by adding mini dsp (balanced)(got this bnib ebay with the software download!) into chain to drive sub amp, and cut down enclosure to just over 2.5ft2(madisound rec. vol) which makes the box more conducive to position experimentation, and added the SS matching passive. an improvement for sure!
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