Hi all. I'm looking at designing my first speaker, and I want to create an LCR type speaker for home cinema use.
To attempt to make things easier, I want to use a woofer combined with a fullrange type driver, crossed over around 500hz using a 1st order xover.
The goals for this speaker are:
I want to make an LCR speaker as I'd like some symmetry and matching speakers all round.For this reason, I have figured woofers around 5" would be most suitable as I will need to use at least two woofers per speaker, and the box can't be too big to the point where it won't fit under a TV. This will also help with getting the xover within 1/4 wavelength.
For the woofer, I was considering the 5FE120 16ohm as I believe it can go into a small cabinet vented, and it's also cost effective. I say I believe it can go into a small cabinet vented as I think I've had some trouble simulating on WinISD. I'm getting a bump in the bass response rather than it being smooth when I've simulated other woofers. If anyone could advise on this, that would be helpful. It's also cheap and has a good basket shape for getting drivers close.Link to it here
I note there is a bit of a sensitivty mismatch, even when using two woofers (around 89db for two woofers vs 91db for the 3FE). Would I be able to add a resistor to the 3FE22, or would I be better off seeking a different combination of drivers for the sake of simplicity? There's also a 16ohm variant, could I use that to lower the sensitivity? Without sounding ridiculous, could I use 4 woofers to make up the sensitivity (although this would probably be too big). They come in 8ohm variants, so would it be possible to wire two pairs in parallel and then connect them in a series to make 8ohm?
For the fullrange, I quite like the look of the FaitalPRO 3FE22 8ohm as it has a small diameter, cost effective and I've read some good things about it here. I believe the size is probably a good balance between dispersion and power handling. Link to it here
For the woofer, I'm now looking into an 8" and going with a single unit. I'm trying to find something smooth enough to cross 1st order at 500hz. I am looking at possibly the HiVi F8 as it seems to be smooth past 2k and is only around £50 per woofer. I'm a bit concerned as I've read people say the parameters can be a bit inaccurate with HiVi.
Happy to take any suggestions on other drivers that can be used for this.
I still have a lot to learn about crossovers so it would be nice to get some idea of what I want to do and order some parts to push myself. I always end up putting myself off making speakers in fear of how difficult it is to create a crossover. I really want to learn more though, which is the main goal of this speaker.
Thanks
To attempt to make things easier, I want to use a woofer combined with a fullrange type driver, crossed over around 500hz using a 1st order xover.
The goals for this speaker are:
- Be able to comfortably handle 95db peaks in my 4x3m living room (combined with a sub + AVR).
- Relatively inexpensive - something around £150 in parts per speaker.
- Maximum height of 65cm externally
- Simple as possible for a beginner
I want to make an LCR speaker as I'd like some symmetry and matching speakers all round.
For the woofer, I was considering the 5FE120 16ohm as I believe it can go into a small cabinet vented, and it's also cost effective. I say I believe it can go into a small cabinet vented as I think I've had some trouble simulating on WinISD. I'm getting a bump in the bass response rather than it being smooth when I've simulated other woofers. If anyone could advise on this, that would be helpful. It's also cheap and has a good basket shape for getting drivers close.
For the fullrange, I quite like the look of the FaitalPRO 3FE22 8ohm as it has a small diameter, cost effective and I've read some good things about it here. I believe the size is probably a good balance between dispersion and power handling. Link to it here
For the woofer, I'm now looking into an 8" and going with a single unit. I'm trying to find something smooth enough to cross 1st order at 500hz. I am looking at possibly the HiVi F8 as it seems to be smooth past 2k and is only around £50 per woofer. I'm a bit concerned as I've read people say the parameters can be a bit inaccurate with HiVi.
Happy to take any suggestions on other drivers that can be used for this.
I still have a lot to learn about crossovers so it would be nice to get some idea of what I want to do and order some parts to push myself. I always end up putting myself off making speakers in fear of how difficult it is to create a crossover. I really want to learn more though, which is the main goal of this speaker.
Thanks
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you often have to pad (add resistors) to the high frequency drivers, you typically do not want to pad down the low frequency drivers. I say give your plan a try. I have never regretted a speaker build, learned something on everyone.
Greets!
Box way too small, each driver ideally 'wants':
Vb = 20*5.7*0.61^3.3 = 22.31 L
Fb = 0.42*68*0.61^-0.96 = 45.9 Hz
Hi GM,
Thanks for confirming that for me. Off my head, it's similar to what I was getting on WinISD. Using the same formula for the 8ohm version, I can see this gets 9 litres Vb, which is very different and explains the people using small boxes.
My other options are to use two parallel 8ohms or two series 4 ohms. The 4ohms ones are getting around 4 litres Vb with that formula. I did read some things about inductance and series wiring so not too sure, will have to look into it some more as well as other woofers.
Thanks
I'm already considering changing to a single 8" woofer (or as big as possible when keeping c2c distance + keeping size down to around 50L) and making the speaker vertical. Same goals as before, but at least this way it could reach lower and be better if there is no sub present. I feel like the smaller format is a big compromise at this budget
Greets!
You're welcome!
Le governs its HF BW, so the lower it is the wider it is and sums in series, ergo reduces BW.
+1 and also have to factor in its polar response WRT driver size, spacing, XO points, which is more flexible with vertical array IME if not doing a two way with wide BW WG.
I do hope the movie room is tiny, because 5" woofers will not produce much for home movie setups.
Also, will there be a subwoofer? If staying very small like you plan, I'd suggest multiple subwoofers placed asymmetrically around the room.
I'm all for doing cool little projects, but realistically, you will need to increase the size of your cabinets to enjoy them. Could try to raise the TV? Hanging it on the wall, or adding a riser. Even better yet, get a projector and screen. No need to spend a huge chuck. I've had fun movie nights with a projector costing less than $1,000 ... and let's face it.. a big 100" screen is very cool and involving! 🙂
Also, will there be a subwoofer? If staying very small like you plan, I'd suggest multiple subwoofers placed asymmetrically around the room.
I'm all for doing cool little projects, but realistically, you will need to increase the size of your cabinets to enjoy them. Could try to raise the TV? Hanging it on the wall, or adding a riser. Even better yet, get a projector and screen. No need to spend a huge chuck. I've had fun movie nights with a projector costing less than $1,000 ... and let's face it.. a big 100" screen is very cool and involving! 🙂
Hi Perceval,
I have a sub and they would be crossed over using my AV amp.
With that being said, I've decided to change to a single 8" woofer and give up on the dual woofer idea. I will go with a vertical stand mount type design, I'll just put the centre lower down, either on the floor or a small stand.
I'm currently looking for a suitable 8" with a smooth response that can be crossed over 1st order. I may update my first post to cause any confusion.
Thank you for clarifying that for me. I'll avoid series woofers for now.
An 8" with a smooth response, and not too much money is the Dayton RS225.
Some TB 8" woofers could also work out.
Hmmm.. you are in the UK, so the Dayton may not be so easy to get.
Check out SBAcoustics. They also have very good woofers for a very reasonably price.
To keep it not too tall, look into their racetrack driver, the 5"x8". I used it vertically in a thin MLTL tower, but you could use it horizontally.
X has done a RS225 and the 10F, which could also give you ideas.
The Faitals are good drivers as well for the wide ranger, but they are indeed very hot, and a rising treble, so they will need to get that under control. ScanSpeak 10F are tamer and easier to deal with, but pricier. Same with the Visaton B80.
The SBA SB10 is reasonably good, smooth enough, cheap enough. It has a 4kHz distortion peak, but I have never been bothered by it, and none of the build online using that driver mention it, so, it flies unnoticed.
Some TB 8" woofers could also work out.
Hmmm.. you are in the UK, so the Dayton may not be so easy to get.
Check out SBAcoustics. They also have very good woofers for a very reasonably price.
To keep it not too tall, look into their racetrack driver, the 5"x8". I used it vertically in a thin MLTL tower, but you could use it horizontally.
X has done a RS225 and the 10F, which could also give you ideas.
The Faitals are good drivers as well for the wide ranger, but they are indeed very hot, and a rising treble, so they will need to get that under control. ScanSpeak 10F are tamer and easier to deal with, but pricier. Same with the Visaton B80.
The SBA SB10 is reasonably good, smooth enough, cheap enough. It has a 4kHz distortion peak, but I have never been bothered by it, and none of the build online using that driver mention it, so, it flies unnoticed.
Easiest IME to use low(est) Qt drivers with low(est) Le = widest nominally flat gain BW:
The box only loads the driver to its upper mass corner (Fhm) where T/S theory peters out, i.e. 40 Hz Fs, 120 Hz Fhm:
Fhm = 2*Fs/Qts'
Fs: Fhm*Qts'/2
Qts': 2*Fs/Fhm
(Qts'): (Qts) + any added series resistance (Rs)
The box only loads the driver to its upper mass corner (Fhm) where T/S theory peters out, i.e. 40 Hz Fs, 120 Hz Fhm:
Fhm = 2*Fs/Qts'
Fs: Fhm*Qts'/2
Qts': 2*Fs/Fhm
(Qts'): (Qts) + any added series resistance (Rs)
Thanks for all your suggestions.
I have considered this woofer as it gets a lot of praise. It looks very smooth up until 2k and then dips, I wasn't sure if this would be an issue with a first order but I guess there isn't any big break up until around 6k so perhaps it wouldn't be an issue. You can get them in the UK but they end up costing a little extra. There's one on Amazon for £79.99 (says only one in stock) which isn't too bad (not sure if there will ever be any more at this price), then on Soundimports EU they'll probably end up around £100 each. This is quite a bit above my budget, but if I could make a good speaker of it then it would be worth considering. I was considering the HiVi F8 and I've also been browsing various other woofers to see if I can find something.
Interesting driver. I've changed the heigh restriction to around 65cm now so plenty more room now
I thought the rising response of the 3FE22 might be beneficial in my living room as it would improve off-axis performance. I am quite set on this one as it has good sensitivity and power handling to meet my goals. The Scan, while I'm sure is excellent, is above my budget for this particular speaker. The 3FE22 is about £18 and the Scan is around £80. I would perhaps try this in the future.
This is new to me, I've not heard of Fhm before. I'll have to read up on that. I don't think the mh-audio site works anymore unfortunately
Thanks. Are you suggesting I can artificially lower the QTS of a woofer if required? In what situation would this be beneficial?
I was wondering if I could ask for your input on inductance/rising impedance of a woofer. I'm considering the HiVi F8 as there aren't a lot of options for smooth 8" woofers in my budget - around £50-60. This woofer seems to have a quite a steep rising impedance according to the datasheet. The Le isn't published either, but I assume this means it's relatively high. This is the impedance sweep:
My questions are basically:
- Is a steeper rising impedance more difficult to flatten?
- Does the Le vary much based on frequency. I've been trying to find answers and I've been reading a lot of mixed things. For example I read somebody say the measured Le is basically worthless as it's measured at 1k, whereas other people just say to use a formula using Le to flatten impedance and nothing more.
- What effect would this have on the low pass filter if it's targeted for 500hz?
Would really appreciate your input on this, or anyone else who is happy to help
Thanks
You're welcome!
No, only raise it. Normally only want a (very) low Qt for max horn gain BW (greater efficiency).
The greater the rise, the quicker the HF roll off.
Right, especially when wanting to use 1st order XOs, best to add a zobel to each driver for flattest max BW.
Depends in that we ideally want at least ~ -24 dB @ 6 dB/octave (90 deg phase rotation) of nominally flat BW from the XO point, i.e. 1st order requires a nominally flat BW out to (24/6) = 4 octaves/360 deg away/1st approximation or 500 Hz*2^4 = 8 kHz assuming no major peaking that otherwise needs damping and/or digital correction.
No, only raise it. Normally only want a (very) low Qt for max horn gain BW (greater efficiency).
The greater the rise, the quicker the HF roll off.
Right, especially when wanting to use 1st order XOs, best to add a zobel to each driver for flattest max BW.
Depends in that we ideally want at least ~ -24 dB @ 6 dB/octave (90 deg phase rotation) of nominally flat BW from the XO point, i.e. 1st order requires a nominally flat BW out to (24/6) = 4 octaves/360 deg away/1st approximation or 500 Hz*2^4 = 8 kHz assuming no major peaking that otherwise needs damping and/or digital correction.
Correct, so will need either a very low Le spec and/or impedance correction.
That said, you'll ideally want it to be in its pistonic/TL modes BW, so in theory the VC dia. must be < ~34400/pi/8000 = ~ 1. 37 cm/0.54", ergo the 3FE22's larger VC falls a bit short at ~5763 Hz, ideally needing to back it up from 500 Hz to ~5763/2^4 = ~360 Hz if wanting 1st order.
That said, you'll ideally want it to be in its pistonic/TL modes BW, so in theory the VC dia. must be < ~34400/pi/8000 = ~ 1. 37 cm/0.54", ergo the 3FE22's larger VC falls a bit short at ~5763 Hz, ideally needing to back it up from 500 Hz to ~5763/2^4 = ~360 Hz if wanting 1st order.
Oh that's interesting, I've not seen this been mentioned before - although I've not looked a lot at passive XOs before. I don't want to ask you a million questions, so I'm trying to seek out some good resources.
For now I've ordered some 3FE22 and I went with the 16ohm ones as they're a bit smoother. If worst comes to worst, I can run them fullrange as some surrounds or something. I just need to think about the woofer and crossover some more. 360hz 1st order sounds a bit low for the 3FE22, so maybe I need to consider 2nd order or other. I actually also have a pair of unused Alpair 12pw sitting in boxes but it seems cruel to use them with a cheap driver like the 3FE.
Thanks as always.
Cheaper doesn't always rhyme with worse. (yeah, no rhyme, I know...)
I've heard more expensive drivers or cabinets sounding worse than a Walmart bought little set.
That's true. I've read some good things about the 3FE22. I will compare them full range to my Pluvia 7.2HD at some point.
Another issue is also the cost. If I actually wanted to make a few more, the 12pw will set me back quite a bit. I quite like the idea of the 8" as well now that I'm set on it, the 12pw has around 50% less surface area. I definitely need to do someting with them though as they've been sitting on my floor for a few years now, sort of forgotten about them. I initially bought them to make a WAW with my 7ms, didn't like them so got the Pluvia 7.2hd which I like. Then looking at xovers and stuff, only active was realistic for a really low XO and I didn't have the spare funds for the extra amps, DSP etc. Plus it would be a nightmare to get it working with surround sound. A passive was the only suitable solution for me, but reading about how hard they are to make just stopped me altogether. That's why I want to go for it now and see what I can learn. I might just go for the HiVi F8 and also DATS v3 to just dive in. Considering a 2nd order now but just looking into the potential cost of the xover parts