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DIY subs

Discussion in 'DIY Speaker & Subwoofer Building' started by riddler, Aug 29, 2001.

  1. riddler

    riddler
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    i read some posts recently where diy sub building was discussed.What im looking for is the post from the gentelman how built his own sub using plans, a shiva driver and bkelec amps/cross overs<br />Im considering following the same past.<br />Unfortunatly i cant find this thread again and the search thingy is next to useless atm.<br />Can anyone help ?<br />the person also posted some useful links.
     
  2. General Skanky

    General Skanky
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    You want Ramius.<br />He went away a few eeks ago, but he's due back soon.<br />Search his name and you'll get 'loads' of info.<br />He uses his PC at work to post here, so you'll only get replies 24hrs after your own post.
     
  3. riddler

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    Thank you very much mr skanky sir <img src="smile.gif" border="0">
     
  4. Ramius

    Ramius
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    Hi.

    I couldn't fine the old threads either.

    Anyway, I suggest looking at the Adire Audio Tempest driver, same ideology as the Shiva but 15" diameter and moves almost twice as much air. (Shiva shifts 1.5 litres, the Tempest 2.5 litres) and is not that much more expensive when all things considered.<br />Unfortunately the Tempest was not available when I made my sub <img src="frown.gif" border="0">

    Have a read of the Shiva and Tempest white papers and the application notes for each driver.<br /><a href="http://www.adireaudio.com/Tech%20Papers/techpapers.htm" target="_blank">http://www.adireaudio.com/Tech%20Papers/techpapers.htm</a><br />All the other tech papers are very good too.<br />Fire an email to Adire Audio with your questions, expectations and goals, they will help you choose a design to suit you.

    Ignore the various posts about the so called 'slowness' of large diameter drivers. Total misinformation. The quickness/tightness of a sub is down to the tuning alignment. It can be made as tight or as boomy as you want. <br />Bass is all about moving air so you need high excursion 12" or even better 15"ers for true extension and decent output.

    <br />BK Electronics <a href="http://www.bkelec.com/" target="_blank">http://www.bkelec.com/</a> now do some high power sub plate amps. However you can get more power for your cash using the MF modules and personally I'll stick to using them. Very easy with a digital amp, straight in, no crossovers to worry about.

    A low Q vented Tempest with 500 Watts up it will be absolutely killer.

    Any more questions, ask away.

    Cheers
     
  5. Ramius

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    Cheers Nic.

    Common sense? No. Just basic sub/speaker design theory. There's so much info on the net for people willing and wanting to learn. It's amazing what you can do with just a little bit of knowledge.

    Cheers.
     
  6. GaryG

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    Riddler

    I'm the UK dealer for Adire Audio. Feel free to contact me if you have any queries.

    <br />Gary.Griffiths@AdireAudio.co.uk
     
  7. Nic Rhodes

    Nic Rhodes
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  8. riddler

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    Thanks for the replys guys.<br />Ive been lurking fore over a month and im enjoying my time here.<br />Now the idea thus far is something along the lines of steveEx.<br />I have one rel Q150 so far and intend to buy another.These will be used in stero to partner my Q65's.Then as i cant buy a servo anymore i was gonna build a big brute of a sub for my lfe.<br />Just hope i can get them all positioned ok.Although to be honest as long as it sounds good where im sat i couldnt give a flying furball.

    The girlfiend isnt too big a problem as she loves homcinema too. As long as we can afford to eat im ok.Although if she knew i was moving her 270ltr fish tank out of the room to make room for another sub i dont think id live long.

    Anyway Ramuis can ya post the link to your webby again please.And how easy are the amps you mention to wire up compared to the sub plates ?

    GaryG expect an email soon..

    And a question for anyone...<br />Once ive set my speakers using the spl at 75db what do i set the sub too ?<br />Using the thx optimode..<br />Thanks for everyones help..<br />Mark <img src="tongue.gif" border="0">
     
  9. Ramius

    Ramius
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    Hi.

    GaryG, I don't suppose you're allowed to post the prices & availability (delivery times) for the Shiva & Tempest here?

    Are you still using the IB in your setup?

    <br />riddler, IMO don't get the Q150 until you have made your killer sub. I believe you'll change your mind about the 'two Q150s setup' when you experience the performance a good DIY sub will give you. If you have room for a low Q vented Tempest (see the EBS design on the Tempest application notes) you'll have a sub in a different league/class/planet/whatever compared to the Q150 (or two Q150s <img src="smile.gif" border="0"> Send all bass to it and you'll be laughing.<br />Yeah, the MF module amps are very simple to wire/use (and excellent value for money). Straight in from your sub out, just a little soldering, use the bass management on your amp, too easy. <img src="smile.gif" border="0">

    riddler, sorry, what link did you want?

    Cheers
     
  10. General Skanky

    General Skanky
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    Now that is a turn up for the books. Gary's been lurking here all this time. <img src="smile.gif" border="0"> <br />I too have been looking into doing DIY subs, ref a chat with Ramius ages ago.<br />IPL were on my list, but now that you are 'available', I wonder if a UK price list is available.

    Really, one good driver with a BK sub plate and an enclosure and you're laughing. Too easy really.
     
  11. Guest

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    Well in all honesty i do believe there are speed issues with sub-bass units. I also in all honesty simply don't believe that anyone would prefer the sound from a single, quality unit over a pair of respectable sub-bass units in a "normal" living room type of enviroment. I have spend quite alot of time with commercially available sub units (but nothing over 15" drivers and no quality diy sub's) and have yet to find a situation that didn't qualify the following:<br />Unless you have a very small listening room there is a train of thought that recommends a 2 sub-set up as almost mandatory.<br />Different folks, different strokes.

    SteveEX.

    [ 30-08-2001: Message edited by: SteveEX ]</p>
     
  12. GaryG

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    Gents<br />My queries and replies on this forum have been as a fellow enthusiast so please direct all questions with regard to Adire Audio/JLH Mosfet amplifier products to me via email, I've no wish to fall fowl of the moderators. Thanks.

    Ramius

    I no longer use the IB in the loft. Although it produces low bass and is acceptable for home-cinema use, I cannot get the 'speed' and 'grip' needed to match my Hi-Fi setup. I've not tried an IB sub before so it was an interesting learning experience. I tried 3 different amp modules with varying degrees of success, the next test would have been to try differenct speaker drivers but I've not bothered because it's doubtful that it would give the control that you get by 'loading' the driver with the use of an optimally sized enclosure.

    I've been beavering away for the past few months trying different designs and amplifiers to meet my (very high) expectations. I prefer the sound of a sealed enclosure (lower group delay) but I'm looking for a sub that takes over from my Kef's below 34hz which would require quite a large box size so I've reached a compromise and have settled (I think! although I reserve the right to change my mind!) on a vented enclosure using twin 15" drivers in an Isobaric configuration driven with a 500w amplifer. Projected frequency response is flat down to 20hz with the F3 point at around 18hz, although I've not been able to confirm this as the frequency plots from the spectrum analyser I've been using aren't very reliable not that it matters I'm more interested in what my ears are telling me anyway, either I like it or I don't, I'm a very black and white person, things are either 'great' or 'rubbish' although I do try to be diplomatic when things are rubbish. I've listened to a quick prototype now for some time and feel happy that it integrates with my main speakers (Kef Reference 4) so this weekend I'm off to the cabinet maker's to get the thing built professionally. It will be a double skinned MDF enclosure (36mm thick in total) built as a box within a box with 2 horizontal and 1 vertical shelf brace (18mm mdf). Hopefully that will give the necessary stiffness to control resonance I don't want to have to start 're-engineering' at this late stage. Once it's up and running I'll let you know whether it was successful or not. Trouble is I've already got my eye on trying something with an 18" driver or two!
     
  13. Mark Grant

    Mark Grant
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    Does anyone else think it would be good to have a new forum for 'Audio Video Tweaks and DIY projects'

    I posted in the feedback forum<br /><a href="http://www.avforums.com/frame.html?http://www.avforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=19&t=000033" target="_blank">http://www.avforums.com/frame.html?http://www.avforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=19&t=000033</a>

    Spectre agrees, just need some support from members now.

    This would keep the good tweaking posts together, as they get lost amongst the general 'chit chat' posts and the moment.

    Mark G.

    [ 30-08-2001: Message edited by: Mark Grant ]</p>
     
  14. General Skanky

    General Skanky
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    Excellent idea.<br />Will you tell Spectre to trawl through all the past posts and put all the DIY ones in the new forum? <img src="biggrin.gif" border="0">
     
  15. Mark Grant

    Mark Grant
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    General and others interested, can you post a comment here<br /> <a href="http://www.avforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=19&t=000033" target="_blank">http://www.avforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=19&t=000033</a>

    Lets have some support for a tweakers forum <img src="smile.gif" border="0">

    Mark G.
     
  16. Ramius

    Ramius
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    SteveEx.

    Of course there are 'speed' issues with subs, but it has nothing to do with the diameter of the driver. If you're interested in reading about transient response, group delay and all stuff 'subwooferish' there are many excellent resources on the net. <br />Here's a couple of links to get you going-<br /><a href="http://www.audioc.com/diy/Information/submanual/sub_manual.htm" target="_blank">http://www.audioc.com/diy/Information/submanual/sub_manual.htm</a><br /><a href="http://www.diysubwoofers.org/" target="_blank">http://www.diysubwoofers.org/</a>

    If you want more let me know.

    Personally I'd prefer one excellent sub in the optimum room position rather than two average ones.

    Steve, make yourself a quality sub. It's good fun, you learn loads and end up with a top performer.

    Cheers
     
  17. JDC

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    chaps,

    'DIY' forum would be really useful - afterall, how many of us get cedia in of a weekend? DIY subs, amps, IR stuff - there's lots tha could be covered & I expect a fair few of us would benefit from advice from the soldering iron wielding boffins out there.

    Also, there is a software package (name & source anyone??) that I used to know of, where you'd enter driver tech. data, cabinet/enclosure details & it'd model the frequency response before you build. I believe it would do this in reverse as well, so of the the 3 parameters (freq. resp./ cabinet dimensions or volume/driver characteristics) you could enter any two of them and it'd calculate the third.
     
  18. Ramius

    Ramius
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    GaryG.

    Did I give you the link to the IB forum?-<br /><a href="http://f20.parsimony.net/forum36475/" target="_blank">http://f20.parsimony.net/forum36475/</a>

    I understood that the IB can give you the tightest most natural bass possible.<br />I pulled this from the IB FAQ page-

    <a href="http://klone-audio.virtualave.net/page101.html" target="_blank">http://klone-audio.virtualave.net/page101.html</a>

    ......7)Which Qts should I choose?

    For an IB, the Qtc of the system is the Qts of the driver. If you like very tight bass, chose a lower Qts driver. If you like the "HT" sound, then chose a driver with a higher Qts. Dual voice coil woofers can be used with a variable resistor in series with the inputs of an unused VC. This allows the "Q" to be adjusted to the listener's wants/needs. One drawback of this is that the power handling is cut by 50%.............

    <br />The isobaric project sounds like a winner. <img src="smile.gif" border="0">

    Cheers

    [ 31-08-2001: Message edited by: Ramius ]</p>
     
  19. Ramius

    Ramius
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    JDC.

    WinISD is a easy to use program excellent for learning the basics.<br />Download from here-<br /><a href="http://www.linearteam.dk/winisd.html" target="_blank">http://www.linearteam.dk/winisd.html</a>

    LspCAD is much more accurate and powerful. Downloadable from Adire Audio (you can only model their drivers)-<br /><a href="http://www.adireaudio.com/software.htm" target="_blank">http://www.adireaudio.com/software.htm</a>

    However, there's lots to be said for using a proven design. <img src="smile.gif" border="0">

    Cheers
     
  20. riddler

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    Ok my reason for the two rels is that ive manage to intergrate one almost perfectly (to my ears/taste). and its just sat next two the main speaker.this is using high level inputs and set up for music.Im thinking stereo subs in almost the same position as my floor standers are going to give me best results in my "cd listening" position.Infact i was even considering rebuilding my Q65's cabinets with active 10inch subs in the bottom , REL or otherwise.

    What i feel the little rel does lack is outright grunt and furniture moving power for movies , hence the tempest/shiva built.

    I do have the room and girlfriends permission to build and place a large sub.(showed her pics of a 5 foot tall twin tempest thing) But the bigger the sub gets , the fewer places it can go.ie in a corner.

    So i have this question...<br />All the adire designs are down ward facing drivers.And having messed around with both foward and downward facing drivers ive found than downward facing drivers are more susceptable to booming due to corners.<br />Anyone else have any comments/thoughts on this?

    I am gonna build a decent sub before buy another rel.So there maybe a q150 for sale in a few months. <img src="smile.gif" border="0">

    And on a final note does anyone know if its possible to buy drivers from KEF ? and what sort of cost the qQ range are ?
     
  21. Ramius

    Ramius
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    riddler.

    Adire drivers can be used in both the down firing position or forward firing. <br />You could make yours forward firing. Just keep the internal volume and tuning the same as the plans.

    I do think though, it was probably the room or that particular sub that was causing the boominess. REL have plenty of down firing subs in their range and I've never heared anyone complain of an REL sub being boomy.

    Wilmslow Audio stock KEF drivers, not too sure if you can get the ones for your speakers though.<br /><a href="https://secure.wilmslow-audio.co.uk/" target="_blank">https://secure.wilmslow-audio.co.uk/</a>
     
  22. bigmacx

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    Here is an <a href="http://www.avsforum.com/ubb/Forum3/HTML/003352.html" target="_blank">excellent thread</a> that follows one guys attempts to build a 'super sub' (based on the Stryke H15 driver). Even if you're planning something a bit less grand it's still full of loads of practical tips on how to build a sub. It also includes photos of the sub during the various phases of development. Since reading it, I've given serious thought to having a go myself. Anyway it may be of some help...

    Mac.
     
  23. Ramius

    Ramius
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    Steve.

    I apologise. I never initially directed any comments at you personally. I replied to your reply.<br />My first statement was a generalisation of the net, lots of misinformation floating around. Even on RELs website there's something about the speed of 10" drivers. This does make people think 'small fast, large slow' which you know is not true.

    I appreciate that your REL is faster than the Servo, different alignments.

    Do you not think it easier to EQ the sub flat rather than use multiple bass sources?<br />I've been meaning to tame a couple of peaks for a long time but I've never got around to it. I had a unbelievable null before I relocated my sub.<br />Did you have any problems of wave cancellation?

    Excellent points in your post, maybe we should start a new thread regarding all of the above and leave this for riddler and his DIY beaut.

    Cheers.
     
  24. Ramius

    Ramius
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    BigMacX

    I was planning on building that this year (the Power15.2), until my brass went on a trip to Aus <img src="frown.gif" border="0"> <img src="smile.gif" border="0"> ??

    <br />That thread is a must read.

    Cheers.
     
  25. Guest

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    Ramius.<br /> Indeed at the time i was using 2 Rel Storms connected as dedicated lfe (i now use the 2 Rel's as stereo left and right with a Servo 15 connected to lfe out - with lfe routed to mains and sub). I discovered several important (to me) issues, one of which being with the aid of various frequency test tones (typically between 15-50hz) i found that a "perceived" in phase response at one frequency (i.e 38hz) will not be uniform at another (i.e 20hz) although blindingly obvious (again simply standing waves/room size etc) we (myself and a colleague who is an ex-BBC engineer) we examined all possibilities given that, for example an amplifier will phase shift it's output the further up the bandwidth it goes which can lead to a "dis-jointing" of high/mid/bass coherency.<br /> This then leads to a quandry in so much as if you choose to use a multiple sub set-up do you simply assess phase relationships via the processor test tone and live with the rest? (not if your me you don't).<br />This can be considered as the only real downside too using several sub's - the standing wave issue.<br />I have considered actively E.Q'ing a single sub but have found the multiple sub affair to be ultimately more flexible.<br />Inherently the ideal is to "pressure drive" the room evenly, in tuning a single sub it must be taken into account that firstly the sub is as you say in the optimum position which for a large unit may not be "ideal" if it needs to be sat 4" off each wall from the corner of the room for instance. Secondly tuning is dependant upon the sub remaining EXACTLY where it is, any deviation from this will most likely require "adjustments".<br />Thirdly whilst certainly being able to "calm`" via EQ the ever nasty peaks you are in all likelyhood still going to suffer standing waves/holes throughout the listening room.<br />Conversely (for me at least) a multiple sub set-up has several key advantages in so much as firstly, positioning you can more or less place the first sub anywhere (within sensible reason) you want and work with the second one alone.<br />Positioning the second sub (with experience) will allow you to apply the standing wave cancellations to the more or less same frequencies that you were originally recieving the peak lifts from, this is not an exact science but once we had realised these possibilities we were able to drastically reduce a +10db lift at 50hz to around 3db with absolutely no loss (or holes) in the driving of the room. (this can be considered as a tiresome affair and particular attention to phase relationships should still be observed).<br />Obviously with 2 units the ability to "suit your taste" with room rearranging is obvious. <br />But probably the most important (to me at least) issue is obviously the equal pressurisation. For me the sub's performance should be "etheral" without jagged edges, if you have a sub that gives you a +7db or more lift at around 40-50hz (which is quite common) and a massive hole at say 28-35hz then what on earth is the point, you are simply hearing different noises at different levels.<br />I tend not to be "swayed" so much by the "absolute" performance (on paper if you like) of a single/pair sub-bass units and am more interested in what they "actually" are doing in a/my room. If you read the thousands of web pages devoted to sub-woofer "in-room" responses recorded by people you will notice that for a given sub there will be "conflicting" results all of which will be attributed to set-up/position/room enviroments.<br />There is certainly sense, if you are after a well integrated and even sub bass performance in assuming that on logistics alone it is far better to buy/design a sub suited to your "real world requirements/situation" than simply buying/designing a monster sub and "hoping" it will "fit-in" (which it most likely wont), and again there hasn't been an instance (in my experience) where the up-grading of single sub offered the "across the board" improvements that adding a second unit did (obviously assuming they are of a good quality to begin with).

    SteveEX

    [ 31-08-2001: Message edited by: SteveEX ]</p>
     
  26. GaryG

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    Ramius

    Thanks for the link. I'm away on holiday for a week so I'll have a butcher's when I get back.
     
  27. Guest

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    Ramius.<br /> Indeed, your points are clinically understood, however at no time did i state a larger driver will be "slower", what i said was my servo (which happens to contain a 15" driver) does not IMHO have the "timing" of my Rel's, (odd given their IB/Ported designs respectively) the actual driver size was not relevant to this statement. This IS NOT a figment of my imagination.<br />Indeed for diy'ers a low Q design is perhaps the "most popular" option but can involve larger enclosures.<br />For what it is worth i think that serious consideration should be made to the "design" of the living room (which is an INTEGRAL part of ANY sub-bass unit's performance) before buying/constructing any (super) sub. Regardless of how "good" a sub may be, it will be exposed to EXACTLY the same acoustic "deviations" presented by a room as a lesser sub will. If you use a "difficult" enviroment (as indeed i do with an almost perfectly square room, concrete floor, block walls and a high vaulted ceiling but dampened down as far as reasonably possible) then, and i do bow to your superior knowledge of design spec's i have too stay on the other side of the fence and say that indeed i have tried (begged/borrowed/stolen) MANY quality sub's and can only say as i have found (with good long term/experienced listening) and in NO WAY would i settle on a single unit over a pair of slightly lesser (or EVEN smaller!) unit's.<br />In fact whilst i appreciate *read worship* all things &lt;20hz there is IMHO no comparison/choice when choosing between a single large sub that may have superior extension and spl's but a horrible uneven lumpy "balance" across the used bandwidth due to the room acoustic variants against a pair of sub's perhaps not offering the same absolute extension or even (perhaps?) spl but offering a smooth no holes, reduced peaks, smaller possible enclosure sizes with much kinder positioning potential.<br />Just MHO (without malice) of course and i can only recommend people to be aware that in a single sub option next to budget the room (or available space within) will play the next biggest part in bass performance.<br />Apologies if this flies in the face of what goes before but i honestly do think i have heard enough (commercial) sub's in enough set-up's to offer this opinion.<br />I will add that, of course reading the many BB's etc dedicated to diy subwoofery that without doubt (based on posted response/performance tables) the level of peformance (based on the unit alone without "external issues") attainable from a properly designed diy sub will on a "pound for pound" basis knock a commercial equivalent into a cocked hat.
     
  28. riddler

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    Why start an new thread ? its all relvent.<br />I was wondering if some on can answer my spl question.

    Once ive set all the main speakers whilst at 75db using the thx optimode disk.<br />What setting should the sub be at ?

    Also i was wondering if its thx spec to send all below 70hz to the sub..If a dvd is thx cetified does this disk have all sub 70hz info only in the lfe track ?<br />any ideas...
     
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    Riddler.<br /> (Nothing concrete what-so-ever hear unfortunately)<br />Firstly there are so many conflicting "opinions" on this some would say 75db across the board others say +3,+6 or even +10db yet one would imagine the first being the "obvious" answer but i cannot say i stick to any thing given the total non-uniform way in which coders use/set the lfe channel, there seems to be no common unified practice there at all. Another (anal?) point is how do you know that the tedt-tone is not being lifted/nulled by your room anyway. I tend to assess output levels "on the fly" as it were. <br /> Secondly Charlie Whitehouse (sorry C.) would perhaps beable to give you specifics per a known THX disc (i cannot find any info that states THX will redress the channel cut-offs regardless on ANY certified disc.) He very kindly carried out some test's for me (using A1 HC equipment and oscilloscopes etc) to examine what frequencies below 20hz were present on the lfe channel in an attempt to assess the "stability" of the "perceptual coding" (see "quite a tech. question - general hardware i think or general chat)<br /> If you leave a post for his attention he may well be able to specifics on certain disc's.<br />For what it is worth (i apologise if i am teaching you to suck eggs here but this is as close as i could get) using Toy Story 2 (THX), main speakers on only (i use power amps for all channels) with lfe sent to sub i have a Rel storm on each L/R front channel and using the X30 external crossover (that comes with the Servo) because it has IMHO a far more accurate and steeper/less leaky slope than the Rel crossovers (which again IMHO are absolutely the weakest link in the Rel armoury) and setting it to approx 50hz (obviously lower than the THX 80hz crossover) listening to the opening scene there was bass presence on both left and right channels which would indicate (in the most crudest form) that there is no encoded redirecting of bass (on the main channels) to at least that frequency (and nor would i really expect there to be).
     

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