WAW / FAST floorstanding Studio monitor - which woofer?

Hi!

I am planning to build a studio monitor in form of a floorstanding speaker. I have choosen this format because I would like to keep it as a closed box and we need volume. The box will be designed in two seperate parts, one part containing the subwoofer and one part containing the Fullrange driver. The "head" of the box with the FR driver will be a little bit wider than the lower part, to improve the frequency response (soon to be modeled).

The whole thing will be build with XPS or foamcore board.

The crossover will be active. I will use a miniDSP or a miniDSP2.

I have already choosen a FR driver, it will be the Omnes Audio BB 3.01. It has a very linear response and everything I read about it sounded brilliant. It is also not that expensive, so at the end, due to the possibility to easily exchange the head of the box, the driver could be changed easily.

Now the big question is, which subwoofer shall I choose?

I have set myself a limit of 120 Euro per driver, but I have not much experience with woofers.

Can you guys help me out and recommend a good and linear woofer in this price range, preferably possible to get in the UK?
It should work well in a big and closed box. if the woofer needs it, there might be a Linkwitz transformation implemented with the DSP, so the woofer should be able to take that. It does not have to play extremely loud, the focus is on linearity and impulse.

Thank you all for your suggestions,

SP
 
It's not a sub but I think what you want is a woofer for a FAST as you need smooth upper end reach to past 500Hz.

Look at SB23NRXS45-8 and use two in parallel. Very low distortion, great xmax and sensitivity in this class.

8'' SB23NRXS45-8 :: SB Acoustics

It was used by Bushemeister in the bookshelf horn thread and achieved 30Hz at 100dB with -40dB distortion in a sealed box.

http://www.diyaudio.com/forums/multi-way/285030-bookshelf-multi-way-point-source-horn.html

Not sure if available in Europe as easily but the Dayton RS225P-8 also looks very good. I have used aluminum version and like it very much. The paper version has higher sensitivity and is smoother.

More details of RS225 in this thread:

http://www.diyaudio.com/forums/full-range/273524-10f-8424-rs225-8-fast-ref-monitor.html

You could do something similar with Dagger and box with two 8in woofers for a floor stander.
 
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Thank you for your suggestions, the Dayton looks a little bit better to me, without having heard either one of them myself.

You are right, I need I woofer! I did not know that the term sub suggests a different thing than a woofer, sorry for that. You are also right with the crossover frequency, I would like to have it below 500 hz.

As I have a mini DSP in this system, i will be able to play around with that easily. I will end up between 200 and 500 hz .

Thanks!
 
Can an admin please change the title of this thread and replace the word " sub" with "woofer"?

Thanks in advance!

I checked my possibilities to get the Dayton drivers, although I really would like to take those, it seems like I would pay at least 100 bucks per driver including postage and taxes, so I think I will look around for something easier to get.

What do you guys think about the
Tang Band W8-2022

W8-2022 - 8" PP Sandwich Foam Woofer - TB SPEAKER CO., LTD.

or the


Tang Band W5-2053 ?

Lautsprecher Shop | Tang Band W5-2053 | Lautsprecher Selbstbau


They both have a pretty straight frequency response and reach both down to the area of 30 Hz. The first one seems a littel bit better, but costs also around 60% more money at the shop I am looking at.


Any thoughts on that or other recoommendations?
 
I actually am in the luxury position to make the box very big, as the speakers are supposed to be floor standing, but obviously, i do not have to :D .

From which values do you abstract the necessary size of the box?

Btw. I just found your Mass loaded flat folded TL design for the wall speakers. I have just build a quite similar speaker with nearly the same meassurements, it is until now only a flat folded TL. I think I will try to add the vent, thanks for this idea!

...talking about this one, at the bottom of the page:
http://www.diyaudio.com/forums/full-range/223313-foam-core-board-speaker-enclosures-147.html
 
From which values do you abstract the necessary size of the box?

Typically, the Vas is about the size you want if you want the driver to easily reach the lowest frequencies possible without EQ. Usually, this is too big to be practical, but half or third of Vas are OK in my experience. Since you are using miniDSP, you can implement the Linkwitz transform to make the sealed bass speaker go from any arbitrary Q to your desired target Q at desired frequency, assuming you have sufficient xmax. There is a spreadsheet in miniDSP website that has the LT calculator which then generates bi-quad EQ coefs to use.

Btw. I just found your Mass loaded flat folded TL design for the wall speakers. I have just build a quite similar speaker with nearly the same meassurements, it is until now only a flat folded TL.

The vent will bring the bass much lower, you may need a high shelf filter to balance the bass and treble though. Something like a 1mH inductor and a 5ohm to 7ohm resistor BSC circuit may work. Use cheap ($0.50) small inductors with ferrite cores for this - no need to spend $15 for a fancy air core. A little fullrange running sub 8 watts doesn't need all the current capability of the big air cores.

Here is 100 units of 1mH, 0.5A inductors for $12!

http://www.aliexpress.com/item/Free...ze-8-10MM-0-5A-whole-pack-of/32260068172.html

These sound great with a small 3in full range.
 
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mayhem13, thx for this recommendation. I did google it and find a lot of positive feedback on this driver, I also saw that it has been used in some speakers above 3k dollar. But I somehow have trouble to find a shop which does sell this driver in the UK or alternatively somewhere in the EU. Do you know one by chance?

xrk1971, thanks again for your efforts. I Just did model the high shelf you mentioned in a different FR project, just to see what it does to the Frequency response.

Am I right that I would need to insert the inductor and the resistor parallel in the signal way?

I am asking because, technically spoken, it looks more like a bell filter with a wide q, rather than a shelving filter. I wonder what I might be doing wrong and how a true shelving filter would be done in hardware (I use those all the time as a mixing engineer, but obviously as a software EQ plugin).

Cheers!
 
Ok, I just did put the two parts in a serial circuit and had something like a shelving filter as a result.... I did play around a little bit and found out that the little I thought I knew about filter circuits did proof to be wrong :D

I always thought that adding a resistor just would lower the output volume evenly, so there would be no sense in on adding this resister in serial after the inductor. The modelling software now shows me that I was wrong.

Anyway, the shelf does cause a drop by almost 12db at 20khz, is the shelf expected to do that much?
 
Anyway, the shelf does cause a drop by almost 12db at 20khz, is the shelf expected to do that much?

For an 8 ohm speaker and a typical baffle, I find that 1mH and 5ohm is about a 5dB to -6dB attenuation at 5k. My model shows maybe 1dB drop at 20k, which can be fixed by adding a small cap like a 0.47uF in parallel with the resistor and inductor.

Here is a simulation of an Alpair A7.3 in a MLTL in 4pi space with and without 5R/1mH BSC - about 6dB compensation is provided. If you use near walls, use smaller R value (have several 1R, 0.5R, 0.33R's on hand to fine tune to taste).


No BSC:
535324d1457028292-fast-floorstanding-studio-monitor-woofer-a7.3-mltl-no-bsc.png


With 1mH and 5R BSC:
535325d1457028292-fast-floorstanding-studio-monitor-woofer-a7.3-mltl-5r-1mh-bsc.png


The broad bump near 2k is the diffraction of a baffle edge.
 

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Ok, then it was just a communication problem. I would call the filter a bell filter and not a shelf.

The 12db drop did only appear when I did put the inductor and the resistor one after another, in serial. If I insert them in a parallel way, then I get the same results as you.

The speaker is very flat and hanging on the wall, is a baffle compensation still necessary in such a case?