I have got four 7" ScanSpeak 18W8546-00 woofers and I would like to make two subwoofers (left+right side) but I have some problems figurering out how to make the subwoofers so they will play as low (Hz) as possible.
www.d-s-t.com/scs/data/18w_8546-00a.htm
I have tried a lot of software simulations but I am not well experienced in constructing loudspeakers so they do confuse quite a bit.
Does anyone have some suggestions for two subwoofers, each with two 18W8546-00 woofers?
And what about the crossover?
www.d-s-t.com/scs/data/18w_8546-00a.htm
I have tried a lot of software simulations but I am not well experienced in constructing loudspeakers so they do confuse quite a bit.
Does anyone have some suggestions for two subwoofers, each with two 18W8546-00 woofers?
And what about the crossover?
They're not my first choice for "subwoofers," but if you already have them...
Having such a low Qts (0.19) you'd definitely want them in a vented box. Play around with WinISD.
As for the x-over frequency, these should go higher than your typical "subwoofer." If you plan to have them as stand-alone subs, however, don't cross too high or you can easily localize them. 80 Hz would be ideal but 100 Hz (or even a bit higher) should be fine.
Hope this helps.
Having such a low Qts (0.19) you'd definitely want them in a vented box. Play around with WinISD.
As for the x-over frequency, these should go higher than your typical "subwoofer." If you plan to have them as stand-alone subs, however, don't cross too high or you can easily localize them. 80 Hz would be ideal but 100 Hz (or even a bit higher) should be fine.
Hope this helps.
@coolkhoa
They would not be my first choice as subwoofers, but I have had them lying around for a year now and now I want to make some use of them.
I did consider integrating the two subwoofers with my existing loudspeakers by placing my current loudspeakers (small 2-ways) on top of the new subwoofers making it into a 2,5 or a 3-way system.
But would a closed cabinet of 30-40 litres be enough? Perhaps with a linkwitz-grainer combination to add some "sub" to the woofers?
If I am going to make a vented cabinet I propably have to use an isobaric soulution because of space requirements.
They would not be my first choice as subwoofers, but I have had them lying around for a year now and now I want to make some use of them.
I did consider integrating the two subwoofers with my existing loudspeakers by placing my current loudspeakers (small 2-ways) on top of the new subwoofers making it into a 2,5 or a 3-way system.
But would a closed cabinet of 30-40 litres be enough? Perhaps with a linkwitz-grainer combination to add some "sub" to the woofers?
If I am going to make a vented cabinet I propably have to use an isobaric soulution because of space requirements.
The Scan Speaks are high max. linear excursion drivers. Two of them (per channel) can take quite a bit SPL on low frequencies when the Linkwitz transform is adjusted "reasonable".
Moreover, when the LR circuit is adjusted for low Q (0.5) this also helps to keep X-max. within reasonable limits.
The loss in level in the lower frequency spectrum due to the low Q alignment is equalized because of room gain in most cases.
So I could get an okay result if I combine the stereosubwoofers with a Linkwitz circuit in a 2,5-way combination with my small loudspeakers?
It is not 110db at 20Hz I am looking for. I am much more interrested in improoving the midrange and add a quick dynamic (but not abyss deep) bass.
From what I can read from the replies so far, It is not entirely impossible for me to reach that goal.... Right?
It is not 110db at 20Hz I am looking for. I am much more interrested in improoving the midrange and add a quick dynamic (but not abyss deep) bass.
From what I can read from the replies so far, It is not entirely impossible for me to reach that goal.... Right?
Absolutely, I`d think so but that`s just me and others may disagree or may have (although I doubt) better suggestion.
Two of those 7" Scan Speaks combined equal more or less one 10" driver with +/- 6,5mm linear excursion.
Just to give You a clue for dimensioning the circuit:
I used Linkwitz transform with a 10" Scan Speak per channel as subwoofer in a sealed box (approximately 40 ltr.) which gave fc of something around 44 Hz (if I recall correctly). I equalised the driver with the Linkwitz to give a new fc=15Hz / Qt=0.5.
I always use a LR 12db (Q also 0.5) high-pass (*) before the LR transform circuit with f3 set to the new fc of the equalised driver.
Now You have -6dB @ 15Hz due to the LR transform and another -6dB @ 15Hz due to the LR 12 db highpass makes for -12dB @ 15Hz.
Due to this arrrangement the beginning of drop off of low frequencies happens quite early as these are low Q filters (as opposed to higher Q filters which cut off steeper or more abruptly). But as I said in my previous post room gain compensates for this mostly and You`ll get deep and more important (IMO) clean bass.
My setup with the 10" Scan speak described above give incredible clean and deep subbass and even when it gets VERY loud they can keep up with the rest of the system (a 8" mid-bass driver!).
Only when it comes to tracks with very weird low frequencies some caution is indicated with the volume.
Two 7" drivers might have even an advantage over one 10" driver as there are two voice coils which can handle power better than one (which is not unimportant when using a LR transform circuit).
(*) I wouldn`t omit an additional high-pass for a very important reason.
LR transform circuits are high-gain circuits when the "old" fc to "new" fc ratio is big. For frequencies towards DC (and some CD`s can contain weird low frequencies) the LR transform gain raise considerable. Without electronic highpass this easily can lead to clipping in the electronic chain already (let alone what happens to Your drivers).
Eventually You could also play with dividing an 12dB high-pass in two 6dB filter parts - one before the LR transform circuit and another at the input of the power amp.
For me ..no doubt You can (but You should consider a rather powerful amp).
Thank you for the much needed reasuring.
I will make my move on the new subwoofers this week and, if the result is what I wanted, I will post a complete step-by-step on the subwoofers.
- And I already have a new amp coming my way. Unfortunalty it is not as powerful as I wished for (Cyrus Power 2x60W) but it will do for now. So I will have a Cyrus Power for mid/high and another for the subwoofers.
I will make my move on the new subwoofers this week and, if the result is what I wanted, I will post a complete step-by-step on the subwoofers.
- And I already have a new amp coming my way. Unfortunalty it is not as powerful as I wished for (Cyrus Power 2x60W) but it will do for now. So I will have a Cyrus Power for mid/high and another for the subwoofers.
I have planned on beginning the project this week so it should not take to long before the project is complete - well the cabinet anyway... The crossover is going to be more interesting.
I am going to build a matrix cabinet for the subwoofers and brand new cabinets for my small loudspeakers.
I am going to build a matrix cabinet for the subwoofers and brand new cabinets for my small loudspeakers.
Are the drivers unequalized (without LR transform) in a sealed box? If so then this would be just normal but with a correctly adjusted LR transform You should be really able to get sufficient levels below 40Hz.
Maybe You`re just missing that sort of a "boom box" effect?
LR-transform equalized systems with low Qt can sound remarkable clean and therefore in comparison with "ordinary" systems of comparable low frequency capabilities they usually sound rather "slim".
It is not uncommon that this kind of precision in bass sometimes can be mistaken as no or to less bass.
I don`t believe it`s an excursion problem. This are long linear throw drivers and they should handle "normal" listening levels in an average sized listening room.
I agree, "punch" is not really what frequencies <40Hz sounds like.
Yes I would check with a sine wave generator and if possible with a microphone in near field measurement to reveal what went wrong.
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