I take your point. Really, I guess the sensible thing here is that I use the right 'tools' for the job, I either go with Erik's 2.5 way idea with the same drivers as I have in my mains, or I go for a 3 way and go back to the drawing board where I probably don't bother using any of the same drivers as are in my mains, but go for what will work the best as a centre speaker. Although in principle I like the 2.5 way idea of using the same drivers as are in my mains, if I go 3 way, then I have the potential to get the best sound I can for my money (even if it is more expensive).
The 2023-K was an £800 receiver, not that cost is any guarantee of ability, but and the specs suggest that it shouldn't run out of steam, especially when only powering 3 speakers. That said, I think you are right, I certainly shouldn't rule out the possibility.
The whole reason why I had the idea to build a centre speaker is because I just can't hear the voices properly (and my wife also complains about it). If I make the centre speaker louder, it just doesn't seem well integrated since the sound quality coming from the centre speaker (good though it is for the money) is a long way off the quality of the mains. So I guess what I am saying is, I want quality over uniformity. If the centre speaker is better than my mains, then so be it (if that happens, then perhaps I'll build some new mains at some point 😀).
Ok, I'm going to keep the 2.5 way idea is a back up plan, in case the 3 way idea gets too expensive and/or complicated for me to realistically pull off. But for now, lets assume that I'm going to build a 3 way speaker where I don't care about using any of the same drivers as are in my mains - I just want a centre that has the potential (if I get it right) to be at least as good quality as my mains but preferably better.
They are both good idea's and as it turns out I can do both (the Pioneer has pre-outs for all channels). I can even run the mains off the Pioneer and the centre off the McIntosh - that would be an interesting test right? 🙂
Thank you very much, that makes sense and is very helpful. In fact, I guess that loss could be quite helpful if I want the voices to be louder without the low frequencies being too loud?
Right, my wife is calling me to help her with something. I'm need to run now, but I will respond to the rest of your post and Erik's posts when I get back. 🙂
Just to let you know, I made a small mistake yesterday. I don't usually use the Edge simulator and I didn't place the mic in the right position for an accurate model. Done correctly, that 2dB loss I was talking about disappears such that there is really no loss at all until below about 100Hz. So 2 x 18W8545 will give you more like 93dB in sensitivity and that makes the Audax probably the only viable mid for that combination.
Thanks for letting me know jReave. 🙂
I'm thinking about going for the AUDAX HM100Z0 mid and an SB Acoustics SB29RDNC tweeter, not sure what woofers at the moment. Not sure if that combo will rival my mains, perhaps it will, but hopefully it will be good. If anyone see's an issue with the selection so far, let me know. 🙂
Ok, so it turns out that what my wife asked me to do took longer than I thought, so I'm going to carry on responding to the remainder of the posts tomorrow.
Thanks everyone so far for your input. I really appreciate it. 🙂
I'm thinking about going for the AUDAX HM100Z0 mid and an SB Acoustics SB29RDNC tweeter, not sure what woofers at the moment. Not sure if that combo will rival my mains, perhaps it will, but hopefully it will be good. If anyone see's an issue with the selection so far, let me know. 🙂
Ok, so it turns out that what my wife asked me to do took longer than I thought, so I'm going to carry on responding to the remainder of the posts tomorrow.
Thanks everyone so far for your input. I really appreciate it. 🙂
Look at the power consumption figure. Look at the conditions for the quoted power (some class D amplifiers have distortion issues at high frequencies). It states 4 ohm stable which is a good sign but it doesn't seem to have a power supply to deliver the current.
Despite being small, losing cone area to a phase plug and being 8 ohm the Audax has a very high efficiency. It achieves this mainly by having an abnormally light cone for home audio which gives it a rather different set of advantages and disadvantages compared to more conventional home audio midrange drivers. What got you looking at it was a need for a small high efficiency midrange due to using midwoofers instead of woofers and an overly large tweeter. These constraints have now gone away.
If I was you, I would build a pair of slim speakers where the magnets of the drivers would get into the rear baffle. I have never heard a conventional system with a center channel where sound would not come from under/above the TV and not from the TV as it should, especially a problem on large panels. Two slim speakers placed on each side of the TV and connected behind it to form a single channel, so to center the image in the middle of the panel, sounds like a much better option to me.
Besides, center channel sound rarely contains anything under 80hz and going for a 3 way sounds a bit like an overkill to me, especially if its your first project ever. Get a pair of FE127 or if you want to spend more - FE168EZ and add some woofer to support them - these excel with voices and your crossover will be lower in frequency and easier to design. I wouldn`t trow lots of money into an AV setup unless it is run by high quality power amps and a separate processor. If its one of the AV receivers - they`re just not up to the task for driver like the Scanspeaks you mention.
Besides, center channel sound rarely contains anything under 80hz and going for a 3 way sounds a bit like an overkill to me, especially if its your first project ever. Get a pair of FE127 or if you want to spend more - FE168EZ and add some woofer to support them - these excel with voices and your crossover will be lower in frequency and easier to design. I wouldn`t trow lots of money into an AV setup unless it is run by high quality power amps and a separate processor. If its one of the AV receivers - they`re just not up to the task for driver like the Scanspeaks you mention.
Thank you for looking into this and for also updating with a correction. Yeah I think I'm better going for the two 4 ohm mid/bass drivers in series. To be honest, as you know, after you posted the above I've been thinking about the whole three way thing without necessarily keeping any of the original drivers with the idea of aiming at quality.
At this moment in time, I'm even thinking of throwing caution to the wind and designing a centre speaker around the ScanSpeak 12MU/4731T00. I know I'd need to give the centre channel better amplification, but that is something I'm willing to do (although budget will not allow me to do so immediately). I really like the 12MU's flat response, it gets great reviews and it's probably the mid driver that I would use to build a new set of main speakers (if I ever do that). As far as tweeters go, here is the thing that is bothering me, I can't find any tweeters that have a small face plate that are nice and sensitive and have a nice response without much change in the SPL, yet I can find a few that are nice and flat with bigger face plates. The thing is, I'm not experienced enough to know how much of a problem an uneven response is. Take the D3004/602010 that Zonneschimmel suggested for example, it looks like it could be a really nice tweeter and has a relatively nice response, except that it has (to my untrained eyes) a rather nasty 3db dip at about 5k. The thing is, what effect is a 3dB dip going to have on the sound at 5k? Is it potentially a problem for a centre speaker? Alternatively, if I allow the faceplate to be bigger (I know it's unconventional for a centre speaker and will raise the height of the unit a little), then for £3 more, I can get something like an SB TW29RN SATORI tweeter that has an impressively flat response (although my concern with the latter is that I'd need to drop it by 5dB to work with the 12MU, again, I'm not sure if dropping by so much is a real problem or not).
Oh that's good to know. Ok, I'll go with a sealed box then... that should save some space too. 🙂
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JWeave,
Yes, 3 way is better, I usually find it rather madening to try to find a quality tweeter and midrange that will fit vertically in the typically low profile of a center channel speaker. Much easier in a standalone that isn't being squeezed under an HD television.
But hey, if you have the space, do it! 🙂
Here's an example I'm working on for my blog. It uses much cheaper parts, but the phase alignment issues are the same. I've attached the XSim data so you can play with it to see what I'm talking about regarding how the phase issues go away, and how the extra driver takes care of the BSC for you. 🙂 This is a work in progress so the part values have not been normalized nor checked for power ratings, etc. I'm only sharing this to help illustrate the issues being discussed.
Regardless of which driver you set as your 0 point, the FR doesn't change very much.
Best,
Erik
Thanks Erik, I'll have a go of playing with that in XSim. 🙂
Yeah, I noticed that, it seems it's quite a common thing in AV amps. It suggests that if I'm not powering the fronts of the amp, that it should have enough juice for the centre... at least, I'm hoping that's the case. 🙂
Does that mean that the there are better mid's for the money that I should look at? At the moment, I'm trying to match drivers for two potential 3 ways, one around the Audax (a more budget 3 way) and one around the 4 ohm Scan Speak 12MU.
The thing is, I'd really like to have a go at building a centre speaker and I do have an upgrade path planned for my AV system (separate processor and 3 channel power amp (for the centre and rears), keeping my McIntosh to power the mains). I would really like to get an Anthem AVM60 Processor, but it's a little beyond my budget at the moment... unless I wait until next years model comes out, so I can get the current model with a reasonable discount. 😀
Thanks, I'll keep that as a possible suggestion, although I'm a little concerned about the 5k dip in the response. That said, minimising the CC distance would be good.
I just looked into the phantom centre, but really still like the idea of building a centre speaker. I might give the phantom centre a try anyway though. 🙂
I've done the phantom and the real. With an Oppo you can try this really easily, and it's somewhat similar but even being off center a little makes the real center worth while. One thing I noticed with having a real center was the tonal balance was better. The phantom center seemed boomier and muffled by comparison. Of course, the Phantom C may vary based on implementation. I did not use Neo6 for this testing, but I do now for all 2 channel in hopes of getting Dolby Surround. It is quite possible the Neo6 decoding matrix does this better.
However I'm totally cheating by using very high end drivers in the L and R and much more cost effective in the Center and Surrounds. I am however matching the FR as much as possible. It works much better than you would think. I found matching amplifiers ( to a point ) was more important than speakers so long as the speakers had a similar tonal balance (measured by OmniMic). Though the amps were 30 years apart. 🙂
Now that I'm switching to ICEPower amps, the ICEPower and Parasound sound so similar it doesn't seem to matter.
Best,
Erik
Best,
Erik
However I'm totally cheating by using very high end drivers in the L and R and much more cost effective in the Center and Surrounds. I am however matching the FR as much as possible. It works much better than you would think. I found matching amplifiers ( to a point ) was more important than speakers so long as the speakers had a similar tonal balance (measured by OmniMic). Though the amps were 30 years apart. 🙂
Now that I'm switching to ICEPower amps, the ICEPower and Parasound sound so similar it doesn't seem to matter.
Best,
Erik
Best,
Erik
Any chance you might consider placing your CC on a tiny stand on top of your AV stand? It's just a thought, as it would perhaps allow for a taller design, would provide more baffle step loss which will mean overall sensitivity would be reduced (not something I would normally recommend, but here in your case it might be a good thing) and will bring it closer to the tv and probably your listening position ear height. Otherwise it might help to know what the maximum dimensions you can allow yourself for the CC in the new stand.
Now personally I think that if you can afford it, upgrading the drivers with an eye to possible future mains matching is a good idea. Let me add though that I just went back to double check on human voice frequencies (see attached) to see that they are in fact going to be produced by both your mid and your woofer so it will be important to go with excellent woofers as well.
Re FR's: in general, a dip is much more benign than a peak. But for the price of that Illuminator tweeter, I would not think that a dip like that is very acceptable.
BTW, SB acoustic and the Satoris in particular are very good choices - the designer is the same man who used to be with ScanSpeak right up to and including the Revelator line. That makes the Satori an excellent tweeter but the face plate has got to be too large for you. The SB29RDNC would better fit your situation but there are other possibilities too I think. I would say though that 1st you need to firm up the dimensions you are working with as well as your woofer choice so that we know the tweeter's SPL requirements. Even finalizing the AV stand 1st may be important because if it's actually more like open spaces with components than like a more flat surface with a few small spaces, then you are likely to get at least some baffle step loss and therefore SPL requirements wouldn't be so high.
I have seen some people cry havoc at the thought of adding resistance to pad down drivers but it is done so often with excellent good drivers in outstanding speakers that I don't worry about it. I have the Vifa XT25 padded down about 10dB to match a Scan 15W Revelator and it still sounds fantastic.
If your are looking at new woofers, I'd suggest looking for ones with an F3 below 80Hz sealed if you can.
Oh, and I think you might be ready for all the driver measurements you can find at Zaph|Audio, looking in particular at harmonic distortion and CSD in order to start comparing driver sound quality. Make sure you include his Blog too.
Attachments
Oh and just in case I haven't given you enough reading material, I was going to add these :
What mid and tweeter for high end 3-way
Post Your "Favorite" Midrange You Have Used! What Sounded The Best?
Your favorite tweeters at different price points
What mid and tweeter for high end 3-way
Post Your "Favorite" Midrange You Have Used! What Sounded The Best?
Your favorite tweeters at different price points
Not really. Better for the money doesn't really apply until it is considered in the context of the overall design. So if your 12MU was £20 rather than £200 it would not be better for the money if the design required 93 dB sensitivity and 8 ohms which the Audax provides and the 90 dB sensitivity and 4 ohms of the Scan-Speak does not.
If you think you may need more Audax drive units in the future I would suggest checking the likelihood they will be available. I don't know the current situation but Audax ceased supplying drivers to the DIY market 10 or more years ago and I am not sure they still exist as a trading and/or independent company. However, batches of their old designs do seem to get manufactured by somebody now and again.
A flat on-axis frequency response with the driver in a large flat baffle is possibly not as important as you currently seem to think. When you put the drivers in a cabinet the response will not be flat. What probably matters more is how easy that response is to correct to be flat. This is the published response of a nice driver but does it look nice to you?
The thing is, in our listening room, we have a two seater sofa, the centre of the room is on not central on either side of the sofa but the right side is closest to being central (the centre line is about three fifths of the way between the left edge of the sofa and the right edge of the sofa, so even if I was considering the phantom centre as a potential solution, I'm not convinced that a phantom centre would work well.
Lol, there is nothing wrong with a 30 year old amp 🙂 With respect to amplification, I'm thinking I'll probably try to buy a good s/h or ex dem 3 channel power amp first (or possibly 5 channel if I want to allow for 7.1 at some stage, though not in my current listening room), using the pioneer as a processor, and then upgrade the pioneer when finances allow.
Yeah that's a possibility as long as the TV doesn't get pushed too high. OK, what I'll do is I'll draw and post a 3D diagram of the stand that I'm planning. Along with some dimensions. I've just realised that I might have said something confusing before, so I think I should clarify, when I said that the centre channel will sit oon the top shelf, I meant the centre channel will sit on the top of the stand.
I was planning on getting two Satori MW16P-4's to use as woofers, but then I noticed that the SPL is possibly a fraction high for the 12MU, the Satori is a little jittery on FR response, but on average, above say 250Hz it sits just above 90dB, below 250Hz it is below 90dB. The thing is, is crossing the mid at 250Hz is too low for the 12MU? I'm guessing that it would be better to cross the 12MU at something closer to the 500-800Hz range?
So here's the thing, my driver budget that I was originally planning for was around the £300 mark, but I can probably go to around the £450 mark at a push. The 12MU would take out £200 of that budget, leaving £250 for the tweeter and woofers. If I go for the SB29RDNC then that would leave a budget of around £220 for the woofers where their combined SPL needs to be a maximum of 90dB. If I need to cross above 250Hz, then I know the Satori MW16P-4 are a fraction high if I linked two in series, but is there a way that I can make it work with a bit of baffle step loss by putting the centre channel on a small stand? Else, are there better drivers that I could use for the woofers that wouldn't push me over budget?
That's good to know, thanks. 🙂
Before I forget, you said the SB29RDNC would be a better fit to my situation than the large face plated Satori tweeter along with a number of others who have also encouraged me not to go for a large face plate tweeter. I certainly don't want to ignore that advice - so please forgive me if it has come across like I'm being like a stubborn donkey by constantly bringing up large face plated tweeters as suggestions. Clearly I'm missing something and I'd like to understand what that something is. So aside from height of the box considerations, I'm not grasping why a large face plated tweeter will cause a problem. My immediate thought was that it could be to do with the distance between the mid and the tweeter when taking vertical phase issues into consideration. But then if that is the case, I'm wondering why is it of particular importance for a centre channel as opposed to mains? Or is it so that I have more room to play with when considering driver placement with respect to baffle diffraction, especially when I stated that I didn't want the cabinet to get too high?
With regards to firming up dimensions, I'll try to draw a 3D diagram of my planned AV stand and provide dimensional limitations on the centre channel cabinet.
Thanks for letting me know, I'm not be so afraid at the thought of dropping by 5dB now. 🙂
When I'm trying to figure out the F3 of a driver, do I look at the first point that the driver drops by 3dB passed it's average, or am I looking for the point that the driver clearly starts dropping off? What about the rise around the Fs, do I ignore it? For example, when looking at the Satori MW16P-4, then if looking for the first point that the driver first looks to tail off and drops -3dB, I'd have picked 90Hz, but then the Fs kicks in giving another rise. So should I be looking at -3dB down from the Fs (i.e. around 32Hz)? The SATORI MW13P-4 seems even harder for me to figure out, due to such a big rise around the Fs and the great lul before it gets down to the Fs.
Thank you very much for pointing me to this, in particular to mentioning what I should be looking at (harmonic distortion and CSD). Also thank you for including the image of the instrument/voice frequency ranges, I found that very informative.
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