You guys aren't reading between the lines, only what validates and yeilds the opportunity to "push" your oh soo extensive expertise. The subs that are built, but unfinished, play very well up to 100hz or so. I have decided to compromise the WAF in my favor and build the mains ported, probably dual driver. I do have quite a lot of EQ to work with built into the receiver which could help (not resolve) some of the thin midbass. If I took alot of your advice as gospel (you know who you are), I'd just say screw it and listen to the TV sound.....which would be soo much better than 7 5" full range drivers and two TH subs. Sorry to be sarcastic......but there are a fairly strict set of limitations in place. I thought I had made that sort of clear @ TS. Do I realize there will be some compromises sonically due to restrictions....definitely. Do I think my plans will completely destroy the auditory movie experience as some of you imply....definitely not. I can't change the room, I can only change the WAF to a small extent, and I'm not willing to ditch the idea based on the opinions/expertise of a few HT snobs as it be.
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JAG -that's interesting. I wasn't aware that all 5in wide-band drivers without exception suffer from a severely narrowing power response with increasing frequency. Ah well, silly me. Obviously I live in some form of alternative reality where some examples of such drivers exist which do not suffer from such issues to anything like the extent you imply.
While from a purely technical perspective much of what you say & are proposing to lecture us on is well-known and unremarkable fact*, you appear to be ignoring the fundamental reality that many people are quite happy with such setups as those you are universally disparaging. Why? Because they do everything they need, and they neither desire, nor require, more. QED, it's not a problem, however much those who are rather more serious about their HT (for whatever reason) might complain about its erstwhile technical limitations or otherwise. As the gentleman points out, he's restricted in how far he can go, and what he is attempting is not a cutting edge HT rig with minimal compromise, but simply something a trifle better than what is built into his TV. Nobody here is silly enough to believe such setups redefine HT. Of course they don't. Can they beat the junk that lurks inside most TV boxes when such a compromise is required? Of course they can.
Me? In an ideal world, being an Altec-head, I'd be wanting for mains a couple of 15in HE woofers mated to compression mids-tweeters, which I assume gives an idea as to what I would regard as approaching optimal for a complete HT setup. But we don't all live in ideal worlds. Lucky you, if you do.
*A minor point, but seeing as we're discussing technicalities, 'doppler' per se is arguably a bit of a misnomer; I assume you are refering primarily to FMD / AMD along with the associated phase shifts. And, just as a reminder, correction for step loss does not automatically have to be passive, or even required. Some drivers have correction actually built into their response which will not be reflected on a graph derived from a driver's T/S parameters.
While from a purely technical perspective much of what you say & are proposing to lecture us on is well-known and unremarkable fact*, you appear to be ignoring the fundamental reality that many people are quite happy with such setups as those you are universally disparaging. Why? Because they do everything they need, and they neither desire, nor require, more. QED, it's not a problem, however much those who are rather more serious about their HT (for whatever reason) might complain about its erstwhile technical limitations or otherwise. As the gentleman points out, he's restricted in how far he can go, and what he is attempting is not a cutting edge HT rig with minimal compromise, but simply something a trifle better than what is built into his TV. Nobody here is silly enough to believe such setups redefine HT. Of course they don't. Can they beat the junk that lurks inside most TV boxes when such a compromise is required? Of course they can.
Me? In an ideal world, being an Altec-head, I'd be wanting for mains a couple of 15in HE woofers mated to compression mids-tweeters, which I assume gives an idea as to what I would regard as approaching optimal for a complete HT setup. But we don't all live in ideal worlds. Lucky you, if you do.
*A minor point, but seeing as we're discussing technicalities, 'doppler' per se is arguably a bit of a misnomer; I assume you are refering primarily to FMD / AMD along with the associated phase shifts. And, just as a reminder, correction for step loss does not automatically have to be passive, or even required. Some drivers have correction actually built into their response which will not be reflected on a graph derived from a driver's T/S parameters.
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Steve (I assume?) -how big a box can you go to for your mains, and where are they likely to be positioned in the room?
Well that's clear so I apologize for intruding and this will be my last post in your thread.
I'm just trying to help you, and anyone else that might read this. If you don't want to hear it I'll quit saying it, right after this post.
Center and surround channels are supposed to have wide dispersion so they can cover the whole audience. 5 inch fullrange drivers are not particularly well known for their above average dispersion characteristics. Can you find a 5 inch fullrange that has adequate dispersion to cover a very small audience? Probably. Is it ideal? Absolutely not. Does ideal matter? See the next point...
Yes, these issues are all well known and yes, people do enjoy systems with flaws. Absolute perfection is not required. The only reason I commented in the first place is because there are so many things working against the critical midbass range in this particular design. They all add up. It would be incredibly easy to avoid some (actually most) of these issues with small changes to the design. But WAF would probably have to be violated to some extent.
All true. But this design in particular needs some form of bsc. Or a 2 square foot suprabaffle. Some drivers have a bit of correction built in but none have the full 6 db that this design needs.
I'm not trying to lecture you Scott. I know you know all this. I was trying to point these things out to the OP who does not seem to be aware of any of it. I know some various flaws and shortcomings are acceptable to certain people depending on their expectations. But there are so many problems with this particular design (especially when you consider the sub's limited range too) that I felt they should be pointed out since I honestly think the OP will be disappointed.
So you commented on my comments and you stated your own personal preferences - which not surprisingly are about as far as you can get from the OP's proposed system. But you didn't actually say whether this particular system is a good idea. I'm talking primarily about the Volvotreter horn and small sealed center and surround w/tang band as shown with no bsc. (The ported mains are a big step in the right direction although they will still need bsc.)
So for the record, do you think this system (including the chosen sub) is actually a good idea that will measure well in room, a system you would personally be happy to own and show off to your friends and at audiophile gatherings?
Ok, but I don't think anyone else is and this isn't my thread so email me through the forum if you like. (I don't check pm's, only email.)
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If this is for home theater, .. look for a suitably inexpensive bunch of 4" woofers and budget tweeters and array them. From experience, .. 3" will roll off in the bass too early to integrate suitably with a sub and 5" (generally speaking) will roll off too early in the treble to integrate properly with a cost effective tweeter line 🙂 . 9 woofers per line would be around the sweet spot.
Regardless of what you chose , Make sure your design gets down to below 100 Hz or else , you'll be chasing your tail forever with respect to subwoofer integration
No argument re the surround channels requiring wide dispersion; that's easy enough to achieve. Centre channels -more of a thorny issue. As an old quadraphonic-head with an interest in analogue matrix decoding & a side-interest in ambiophonics I have a slightly different take on such devices. Wide dispersion is theoretically nice to be sure, but in practice? Different story. It certainly does its job at improving dialogue imaging for off-axis viewers, but the price can be, and often is interferance with the mains on badly mixed material (that's most of it then). Perhaps even more to the point, I never quite worked out why anyone who is presumably serious about HT would then sit so far off axis as to be worried about such things.
While none are ideal (nothing is) some are acceptable enough in some situations where outright performance is not the goal, esp. given the aforementioned points. Dispersion / beaming / whatever you want to call it mostly it comes down to driver design & particularly cone profile, so as in everything else, you select the best available compromise.
Unfortunately from a performance POV, that does not look likely to happen, as the OP stated clear from the off, so you work with what you can. Given that he has not made any final choices yet, I'm puzzled why you're automatically assuming the worst case senario.
As it happens, I could mention a couple of forthcoming drivers that do have that level of correction built in. However, see above: what design? There isn't one yet.
Read my post again. What I said was in an ideal world, to illustrate the fact that I am well aware what outright performance entails. However, we don't all live in ideal worlds; if you do, you are a very lucky man, & I'm genuinely happy for you. What I would actually do would vary according to the specific situation I found myself in.
So, re your question, as we are still discussing options, it's impossible to give a definitive answer. The best I can give you is that given the general requirements / restrictions, I think something along the general lines the gentleman is looking at should suit reasonably, as optimal sonic performance is unfortunately not the priority; having something that will beat the junk in the TV & please his good lady are the goals.
I didn't realise that any of those were yet set in stone. And vented mains will not necessarily need electrical correction for step loss; you can avoid that via some cunning design. Depends on where they are to be positioned, and how large we can go to with the enclosures.
See my above answer. As for showing off to friends & audio-nut gatherings, given that it has been repeatedly stated that ultimate SQ (as in sound quality, not the CBS matrix quadraphonic system), is not the object of this system, I'm not sure what you're trying to prove here. What would you learn? That a system not designed with all-out performance as the priority is beaten on that score by one that is. It's a bit like the 1 mile drag race between the Mclaren F1 and Bugatti Veyron Top Gear held a year or so back in Dubai. As Clarkson sardonically put it afterwards, 'What we've proved there is that the Bugatti Veyron, which we know to be the fastest car in the world is faster than another kind of car. You don't get that kind of information everywhere.'
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I was just now contemplating using the TH subs as stands for the mains, as it might keep the spouse happy if I avoid taking up more floor space. The subs measure 8.5"Wx16.25"Dx24.125"H. If using the same footprint for the mains using 3/4" material, provided my math is correct, I could do as much as a 1.5ft cab, without exceeding a 20" cab height. I'm having trouble in winisd getting rid of a big peak between 100 and 115 when tuning below 60hz. I'll play with it some more tonight. Almost forgot, mains will be on either side of the EC, between 8 and 10ft. apart. I know that's not ideal for channel separation, but she wants things compact. Also, if the mains are very close or up against the back wall, correction for baffle step becomes negligible....if I understand correctly?
Thanks for the help.
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A variation on the Twin CHR-Ken (CHR-70) or Twin Mar-Ken70 would easily fit within that criteria.
The Twin A7 DBR is already 8x20.25x12 (wxhxd)
dave
The Twin A7 DBR is already 8x20.25x12 (wxhxd)
dave
Ha! Talk about irony. Because I was literally just checking to see how well one of the TB units under discussion would work in the twin A7 DBR box. Rather well is the answer. Quasi anechoic attached for that cabinet with the TB, pretty much preserves the pro-audio alignment I built into the response for the twin A7s. The MA drivers would still be my option though; they're technically superior units with excellent dispersion & pretty much self-correct for step loss in practice, but they are more expensive, so depends how much you want to be spending.
Attachments
It was supposed to get put up on Mark's (markaudio.com) plan pages. It, and the A12 DBR, are now linked on the P10 MA box plan pages planet_10 hifi
dave
dave
>>> Thanks,
>>> Exactly what I was looking for, thanks. Might you be so kind as to give me
>>> one more sim tuned slightly lower @ about .75 cu.ft.
My pleasure! Turns out i had jury duty today (and yesterday) so working in office until around midnight to make up the work (self employed). Got out of jury duty tho! This is a nice distraction before i start work tonight.
I modeled a single TB in a .75 box and it's a 2 x 2" port tuned to 55hz. You get to 50hz this way. Personally, i like your idea of sitting them on top of two subwoofers doubling as stands. You can be creative with the cabinet shapes and get something clean looking. I prefer the smaller .5 cf cabs frequency curve. The smaller cab will give you slightly better power handling bc not taxing the driver as much in the low frequencies and you get low enough to integrate the subs without any trouble at all. I don't think you need to play with two drivers per cabinet and believe it will muck up the lovely full range driver sound you will achieve with just one driver. You should have a kick *** system with five of these plus two subs without worry it won't play loudly enough. It may not bother the neighbors or shake the rafters but it should go loud... and they should play music really nicely too!
I simmed a BIB too but since you decided on the subs you probably don't want two lovely towers 60" x 9" x 12" in your room... and you need corners to make them rock so maybe not optimal. Maybe someone else will build BIBs with these TBs?
>>> I'd be wanting for mains a couple of 15in HE woofers...
Scott, i have the lowly Alpha 15's in H-frames and believe i have found THE bass solution for my room. I am very pleased with 15" woofers and wonder if anything less would suffice in the future. What i choose to sit atop them is my business... currently it's the TB 1808... but that can change of course! I have had my eyes on a pair of Alpair's for quite some time and expect come the holidays i will actually get to hear them live and in person.
Zilla
>>> Exactly what I was looking for, thanks. Might you be so kind as to give me
>>> one more sim tuned slightly lower @ about .75 cu.ft.
My pleasure! Turns out i had jury duty today (and yesterday) so working in office until around midnight to make up the work (self employed). Got out of jury duty tho! This is a nice distraction before i start work tonight.
I modeled a single TB in a .75 box and it's a 2 x 2" port tuned to 55hz. You get to 50hz this way. Personally, i like your idea of sitting them on top of two subwoofers doubling as stands. You can be creative with the cabinet shapes and get something clean looking. I prefer the smaller .5 cf cabs frequency curve. The smaller cab will give you slightly better power handling bc not taxing the driver as much in the low frequencies and you get low enough to integrate the subs without any trouble at all. I don't think you need to play with two drivers per cabinet and believe it will muck up the lovely full range driver sound you will achieve with just one driver. You should have a kick *** system with five of these plus two subs without worry it won't play loudly enough. It may not bother the neighbors or shake the rafters but it should go loud... and they should play music really nicely too!
I simmed a BIB too but since you decided on the subs you probably don't want two lovely towers 60" x 9" x 12" in your room... and you need corners to make them rock so maybe not optimal. Maybe someone else will build BIBs with these TBs?
>>> I'd be wanting for mains a couple of 15in HE woofers...
Scott, i have the lowly Alpha 15's in H-frames and believe i have found THE bass solution for my room. I am very pleased with 15" woofers and wonder if anything less would suffice in the future. What i choose to sit atop them is my business... currently it's the TB 1808... but that can change of course! I have had my eyes on a pair of Alpair's for quite some time and expect come the holidays i will actually get to hear them live and in person.
Zilla
Attachments
I'm looking at building using vertical arrays of 9 NS3 type 3.5" drivers series/parallel wired per surround speaker with possibly a tweeter to extend the high end (suggestions welcome for what might be the best tweeter which should also not be wider than about 3.5", or whether a tweeter is even desirable here for a HT application ), along with subwoofers. I was thinking of building the arrays into 5" diameter schedule 40 PVC pipe with a 'flat' added to one side for driver mounting, appropriately painted, or how about a wood veneer wrapped around them for a different look? I imagine a surround configuration like this would allow plenty of placement flexibility - weighted base for stability of course.
I'm experimenting with increasing surround compliance of the NS3 type driver and have succeeded in getting an experimental driver to an Fs of 75 hz - according to my modeling, this should allow a F3 point in a non ported enclosure of just over 60hz which I believe would be a very good frequency to xover to the subs at.
Looking promising so far. If I can push the Fs down a few more hz, I think this is a done deal.
I'm experimenting with increasing surround compliance of the NS3 type driver and have succeeded in getting an experimental driver to an Fs of 75 hz - according to my modeling, this should allow a F3 point in a non ported enclosure of just over 60hz which I believe would be a very good frequency to xover to the subs at.
Looking promising so far. If I can push the Fs down a few more hz, I think this is a done deal.
IMHO, for a such small driver, a BSC is a must. Alternatively is by using AV receiver midnight listening, adaptive dynamic range, DRC, loudness or EQ(higher end model only)
However, DRC only work better with Dolby content.
Very little or no effect on DTS content.
On my listening experience/experiment for Pioneer AV receiver with Visaton FRS8M(This speaker have 88db/m & 50w) in a small room.
All speaker are direct connect to amp and set to small without any passive filter / crossover.
Midnight listening mode - increases the low mid/mid bass region to act as a BSC effect and DRC double as a excursion limiter.
Loudness w/o DRC - have increased treble and midbass but sound too bright and be extra careful about dynamic range
Loudness with DRC - produce better result in controlling excursion but treble still too sharp for my taste.
MCACC - to emulate BSC by increasing the mid bass region sound ok.
Summary: MCACC + midnight listening + drc + high volume listening = Really doesn't sound like a good HT system but it really push the limit of small driver to play loud.
The limit factor for small driver is excursion.
Well, if a small driver have too much X-max . It won't sound good as well, as the cone is flapping and affect the mid/high region.
Experiment with high pass filter/X-over will also another way to control X-max.
But I find it anything higher than 100 doesn't sound good. Perhaps due to small room
acoustic & resonant.
Before I forgot, the speaker become uni-direction at above 10khz. So, small 0.6inch tweeter is needed for omni-direction coverage.
Thanks
However, DRC only work better with Dolby content.
Very little or no effect on DTS content.
On my listening experience/experiment for Pioneer AV receiver with Visaton FRS8M(This speaker have 88db/m & 50w) in a small room.
All speaker are direct connect to amp and set to small without any passive filter / crossover.
Midnight listening mode - increases the low mid/mid bass region to act as a BSC effect and DRC double as a excursion limiter.
Loudness w/o DRC - have increased treble and midbass but sound too bright and be extra careful about dynamic range
Loudness with DRC - produce better result in controlling excursion but treble still too sharp for my taste.
MCACC - to emulate BSC by increasing the mid bass region sound ok.
Summary: MCACC + midnight listening + drc + high volume listening = Really doesn't sound like a good HT system but it really push the limit of small driver to play loud.
The limit factor for small driver is excursion.
Well, if a small driver have too much X-max . It won't sound good as well, as the cone is flapping and affect the mid/high region.
Experiment with high pass filter/X-over will also another way to control X-max.
But I find it anything higher than 100 doesn't sound good. Perhaps due to small room
acoustic & resonant.
Before I forgot, the speaker become uni-direction at above 10khz. So, small 0.6inch tweeter is needed for omni-direction coverage.
Thanks
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These work out almost perfect dimensionally, fitting within the footprint of my TH subs, so I can use them as stands. This puts the top driver @ a height of roughly 41" taking footers into account, right at ear level. Even though the graph is in 5db steps, it looks to be -3 @ 68-70hz.......great for integrating with the subs. It's decided, this will be the choice for mains, loaded with 1611 drivers. Thank you much Scott.
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You're welcome. As you're running twin subs, I think they should be a reasonable compromise given your particular situation.
Just to be clear, you can only use one of the Tang Bands per enclosure if you want to preserve this alignment -it's higher Vas precludes employing twin drivers per channel, as was used with the two Alpair 7s the cabinet was originally designed for. I would strongly advise retaining the removable back; it makes access to the interior to tailor the damping much easier (I should probably say 'possible' in the case of the lower chamber) -just make sure the seals are airtight & you should be fine.
As ever, YMMV. We can't promise giant-killing HT performance, but you'll have something better than you've got in your TV set. 😉
Just to be clear, you can only use one of the Tang Bands per enclosure if you want to preserve this alignment -it's higher Vas precludes employing twin drivers per channel, as was used with the two Alpair 7s the cabinet was originally designed for. I would strongly advise retaining the removable back; it makes access to the interior to tailor the damping much easier (I should probably say 'possible' in the case of the lower chamber) -just make sure the seals are airtight & you should be fine.
As ever, YMMV. We can't promise giant-killing HT performance, but you'll have something better than you've got in your TV set. 😉
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It will never work unless it can handle 1800 watts of certified THX power. They will blow after the first few elephant steps at the beginning of Lion King.
If you decide to buy those new TBs please keep us posted on their sound. Good luck with your project and enjoy!
Zilla
If you decide to buy those new TBs please keep us posted on their sound. Good luck with your project and enjoy!
Zilla
An interesting aside: recently read a review of a $500 Pioneer THX receiver. 120W/channel. 90 W 2 channels driven. <30W 5 channels driven.
dave
Will do, drivers should be here in about a weeks time. They'll get a few hundred hours break in on a t-amp, I'll post some impressions then. Thanks for bringing some humor back to the thread. I'll link this thread in a new build thread when I've made some progress on the mains.
I've got a pair of the W4-1320SJ here and have been considering the ML GM-Voigt (Dave sent me the plans, thanks). However I do wonder if I can achieve something more with (imho) these wonderfull bamboo drivers by matching them in a suitable enclosure and a suitable sub. One item coming to mind is a woofer in a H-frame (prefer to keep it relative small, can I get away with a 12"?). Would appreciate your (and Dave's / Scott's) views on this.
Many thanks in advance, AM
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