premium sound stage

Hello all, I have read many posts on this forum and thought that I may share some of my thoughts and almost 30 years of knowledge with you in regards to a premium low-mid / mid-high system. I am not the be-all and end-all in this field and hence welcome all to respond and share their knowledge... so as others may learn (myself included - you are never too old or young to learn). I design high end audio in Australia... I will not (and cannot-so I am told by the stickies) advertise my company or web site - so I will keep that information to myself. I am here solely to share knowledge and not to promote any product(s) - beit my own - or any other manufacturer. (it maybe wise of you to go make a coffee at this point... I feel like writing today.... lol) Overview: as many of you will already understand, a car is quite a hostile enviroment for a Hi Fidelity sound system. Car audio manufacturers are constantly having to 'compromise' in such things as: 1) Available storage / installation space (the lack there of) 2) a 12 volt system for power 3) a cramped or 'closed in' listening arena - with dramatics emphisizing on reflections 4) micro sizing components (again lack of space) etc, etc... Some of the above make for massive compromise in audio fidelity and over all quality sound. The elecronics (head units etc.) have not been overly affected by size (micro sizing) - as silicon chips and the majority of components within a given head unit have steadilly been decreasing in size for many years without affecting quality... the Speaker systems on the other hand are a compromise in almost every facet of their being - as opposed to a 'home' HiFi system... and none moreso than the tweeter. Micro sizing the tweeter in any system is going to have adverse affects. Many of you reading this post will be into db drags... that need not change (and I am not here to talk you out of that) - although, I can tell you that this information could possibly change your view on your current system... Imagine if you will a sound stage (low-mid / mid-high) - both front and rear that sounds sweeter, more neutral, more life like and able to keep up with - if not surpass the power of your subs. This system can add a taughtness and clarity that you would not think possible. All this and more yet costing but a fraction of a premo 'home' system - in your car... you need to be open minded about the components used here, yet I assure you it can be done!!! There is a current trend leading towards 'Ultra-Fi' - as opposed to mediocre sound (in this I am referring to the 'sound stage' and not to the Subwoofer set-up) in automobiles. More and more people are looking for 'high-end'... and coming up empty. One reason they are not finding 'that' sound is because manufacturers have paid more attention (I am generalising here) to 'db' competitions - in where the Subwoofer is king... the other speaker components ie: the humble tweeter, has suffered the most due to the fore mentioned 'micro-sizing' - although an alternative to that average sounding (complete) system is very much available - an '8 ohm' speaker set-up. Companies like Scan-Speak, Vifa, Peerless and Focal make some of the best drivers the world has to offer, some of these drivers are in speakers systems costing upwards of $60k a pair. Now many of you are possibly thinking to yourselves that it cannot be done... or that the amps will fry (4 ohm) - ahh but if we Parallel the fronts and backs (ie: front left with rear left) - as a complete side, it can be done. The Amp(s) will see 4 ohms. To overcome any issues with cross-overs the entire speaker system can be purchased in kit-form (including the x-overs). In the USA there are many Co's that provide this service... Madisound is but one of many that provide the above named drives in kit-form along with the x-overs to match. An excellent Scan-Speak '2-way' stereo speaker system can be had for a very reasonable price. Everything is included... moreover you can buy the 'drivers' only - without the cabinets. This kit type service is also available in Australia (D-S-T, WES Audio among others), Great Britan and many countries in Europe. Type in the specific driver manufacturer in your country into your search engine. Driver sugestions: VIFA system Vifa SOLO, 5" mid & 1" textile tweeter - supplied by madisound.com - cost US$220 per pair (that is one complete side of your system). Vifa STUDIO, 5.5" mid & 1" wave guide super tweeter - supplied by madisound.com - cost US$315 per pair (that is one complete side of your system). ScanSpeak System ScanSpeak SOLOIST, this system has to be custom changed as it comes as an MTM design (mid tweeter mid) - ie: tweeter in the middle of 2 mid-woofers. The system consists of the 18W/8545K 6.5" mid-woofers and the 9700 Revelator (world renound as the ultimate tweeter regardless of cost). The supplier in your country should be able to custom design the x-overs for the single 6.5" mids / tweeters set-up. (x-overs are price per supplier - ScanSpeak drivers are not cheap... you really do get what you pay for here) To match this set-up of mid woofers and tweeters in Parellel 'front to back' a generous (400w plus per Ch @4 ohms) amplifier will be required (more on amplification and set-up below). Yes... there is a compromise here, it is the tweeter size (approx 4" / 100mm dia) - but I can assure you that the difference between almost every 'car tweeter' ever made and say a 'ScanSpeak Revelator' tweeter - is absolutely astonishing. When you listen to these speakers for the 1st time you will be blown away by the realness and emotion of sound quality. It goes without saying that those of you with little or no prior experience in installing speaker systems... should leave this 'ohm changed' set-up to a professional. What you are essentially looking at purchasing is 2 stereo pairs of 2-way speakers... including the cross-overs yet excluding the cabinets. Set-up: The drivers that you purchase will have known TS (Theile-Small) specifications. These specs are critical for the Mid-woofers that will be mounted on the rear parcel shelf - as they will require a 'tuned' and sealed box to be created and mounted into. This box will itself be under the parcel shelf. It will serve as an enclosure to a) isolate it from the subwoofer... and b) to cut off driving the frequency at which your subs are limited at their ceiling (uppermost freqency limit). A trained installer or box builder experienced in designing enclosures for speakers is best left to do this task. 'IF' you run the Mid-woofers in 'free air' ie: just mounted directly to the parcel shelf - without any enclosure below them (and you are running powerful subs either in boxes in the boot - or also directly cut into the parcel shelf - in 'free air') you will blow the Mid-woofers. For sheer sonics as well as higher output levels of the 'sound stage' - the tuned and sealed boxes for the new Mid-woofers is a must. The tweeters should be placed preferably behind the Mid-woofers ie: further away from you than the Mid-woofers (this is for time alignment - albeit small... there is a difference to the overall sound) I am desperately looking for a way to upload these diagrams of what I am trying to explain to you here... lol... without any joy. Those interested in this subject please let me know how to upload pictures etc. TY. The front section of the sound stage is more crutial in placement of the tweeter (for the afore mentioned time alignment). Pods should be designed that will include the tweeters, the tweeters should be mounted above the mids (closer to the door window) yet no more than half an inch away from the mid. To time align - the 2 drivers voice coils should be centred to one another (again I need to show a diagram of this... sheesh). If you place both drivers on a flat table or surface (magnet on the table - yet taking great care in not letting the magnets touch) and look side-on at both drivers at the same time... you will notice that voice coil centre (approx centre of magnet structure) is 'almost' yet not quite (due to thicker mid magnet) at the same level, now... gently lift the tweeter until you see the tweeters magnet is at the exact middle of the mids magnet... ok... done? Now while holding the tweeter in this position glance at where in proximity each 'face' of both the mid-woofer and tweeter are in relation to each other... the tweeters face plate should be quite a bit lower than that of the mid... it is this difference in measurement between the 2 drivers that you need to build into your Pods. Essentially the tweeter should be slightly further away from you that the mid-woofer. (I so need to share a diagram here) This off-set driver aproach is known as Time Alignment. Remember we are now using drivers of World Standard, this tweek is an important factor when using such sensitive drivers of refined quality. Not only are the drivers Time Aligned - they should also be positioned so as they are angled towards the centre of the car. All this tweeking will be well worth the effort... but there is more... Amplification: These 8 ohm drivers Parelled together per side are going to be hungry, I suggested earlier a 'minimum' of 400w @ 4 ohms per channel - yet do not limit yourself to that figure 'IF' you are knowlegable on this subject (ie: you know not to clip your amp from over driving). I have seen a few posts here on the subject of 'transient power' - so I will only briefly touch this subject because in this instance it has relevance. Note: although I deal with audio on a daily basis 'car amplifiers' are not my usual field... so should I mis-direct here please feel free to correct me for the benefit of all. Transient power is essentially 'Headroom' - or - a non stressed electonic enviroment. Example: Let us say that you have a very small car ie: a Fiat Bambino (500cc motor), if you were to put (if they would fit... lol) 5 passengers in that car its engine would be struggling badly to produce any power and its maximum power would not be realized. Ok... so take that same Fiat and lol... shoe horn a Chev 454ci big block into it... well that engine (even with the 5 passengers) wouldn't even break a sweat. It could easilly reach maximum power output in a scarily quick manor - THAT is transient power... the ability to easilly produce the goods. Audio works in a simular fashion, if a speaker (in this case our Ultra-Fi drivers) are rated at 100w per mid-woofer / tweeter and the amp we are going to use to drive them is also 100w per given channel.... the amplifier will always be working hard - although the safe guard here is that when the amp clips (a squared sine wave state - or DC current directly to the speakers ie: maxed out) the speakers are very close to their maximum level - giving you warning of when things are going awry. Now if we have an amp that is capable of producing say 400w per channel and connect it to that same 100w speaker 2 things are going to occur, A) The amp is easilly going to drive the speaker and add a clarity to the system that was not there before - due to relaxed running to produce the same level of output (a good thing) and B) 'IF' not careful the speaker can be easilly over driven past its maximum power threshold hence destroying the driver(s). As I stated above if you are 'knowledgable' and understand power ratios in your system set-up then feel free to experiment as this 'transient' power will make your audio system shine. However lol (always a catch huh)... should you be a novice / newbie in the audio field then either leave the system set to a 'maximum' of 400w - or get a dedicated limiter / compressor with a viewable dashboard readout and have the limiter set to just a smidge below your speaker systems uppermost limits. This way you can still enjoy the added wattage via the superior quality and your amps will work effortlessly. Needless to say that in such a high calibre set-up as I have stated above should definately include - very high quality inter-connects 'without' touching or running close to Power cabling. Speaker leads running from the amplifier to all 4 corners should be of the exact same length, also deadening (Dynamat or the like) in doors, rooflining, under rear parcel shelf and the trunk lid. There are many posts on these subjects here. I hope this mammoth 'novel like' post will aid some of you in redefining your thoughts on the possibilities of what 'can be' done towards producing an audio system that would not only be heard 'crystal clear' many blocks away... and enhance your over-all system.... but you would have something that not many others could boast on having - a true 'Ultra-Fi' car audio set-up. Again - if you have any feed back on this post I certainly welcome it. Cheers STEVEFutureFone Acoustic

Hi Steve!  Welcome to the Forum.  I thought I would add some thoughts.

spin06 wrote: Yes... there is a compromise here, it is the tweeter size (approx 4" / 100mm dia)

A couple other compromises to a larger tweeter is upper extention and earlier beaming which could be an issue in some installations.  I believe a tweeter should be matched to the woofer being used.  If the woofer allows for it, I believe a smaller tweeter could be ideal.  I'm not saying you are wrong as those tweeters you list are very nice, I'm just offering a devil's advocate stance.

spin06 wrote: The drivers that you purchase will have known TS (Theile-Small) specifications. These specs are critical for the Mid-woofers that will be mounted on the rear parcel shelf - as they will require a 'tuned' and sealed box to be created and mounted into. This box will itself be under the parcel shelf. It will serve as an enclosure to a) isolate it from the subwoofer... and b) to cut off driving the frequency at which your subs are limited at their ceiling (uppermost freqency limit). A trained installer or box builder experienced in designing enclosures for speakers is best left to do this task. 'IF' you run the Mid-woofers in 'free air' ie: just mounted directly to the parcel shelf - without any enclosure below them (and you are running powerful subs either in boxes in the boot - or also directly cut into the parcel shelf - in 'free air') you will blow the Mid-woofers. For sheer sonics as well as higher output levels of the 'sound stage' - the tuned and sealed boxes for the new Mid-woofers is a must. The tweeters should be placed preferably behind the Mid-woofers ie: further away from you than the Mid-woofers (this is for time alignment - albeit small... there is a difference to the overall sound)

I don't get why you are discussing soundstage with rear speakers.  To my knowledge, there are no stereo recorded CD's available with imaging cues intended for the rear.  Soundstges are usually recorded to be in front of the listener (except for maybe quadraphonic recordings or the like).  Also keep in mind that running the rear speakers on the same channel as the front speakers will greatly limit your level adjustment abilities between them.  And any potentiometers added to correct this could adversely effect the passive crossovers.

spin06 wrote: The front section of the sound stage is more crutial in placement of the tweeter (for the afore mentioned time alignment).

 

Actually it isn't time alignment that would make a difference with tweeter placement, but output level differences.  This is because we get our imaging cues from level differences for higher frequencies, not from the time domain. 

spin06 wrote:  Pods should be designed that will include the tweeters, the tweeters should be mounted above the mids (closer to the door window) yet no more than half an inch away from the mid.

 

Can you explain why having the tweeter on top will help?  I will agree that if you can get the tweeter so close to the mid, that would be best.  However as a general rule, you can go out as far as the wavelength of the crossover point with the tweeter without negative audible effects.

spin06 wrote:  To time align - the 2 drivers voice coils should be centred to one another (again I need to show a diagram of this... sheesh). If you place both drivers on a flat table or surface (magnet on the table - yet taking great care in not letting the magnets touch) and look side-on at both drivers at the same time... you will notice that voice coil centre (approx centre of magnet structure) is 'almost' yet not quite (due to thicker mid magnet) at the same level, now... gently lift the tweeter until you see the tweeters magnet is at the exact middle of the mids magnet... ok... done? Now while holding the tweeter in this position glance at where in proximity each 'face' of both the mid-woofer and tweeter are in relation to each other... the tweeters face plate should be quite a bit lower than that of the mid... it is this difference in measurement between the 2 drivers that you need to build into your Pods. Essentially the tweeter should be slightly further away from you that the mid-woofer. (I so need to share a diagram here) This off-set driver aproach is known as Time Alignment. Remember we are now using drivers of World Standard, this tweek is an important factor when using such sensitive drivers of refined quality. Not only are the drivers Time Aligned - they should also be positioned so as they are angled towards the centre of the car. All this tweeking will be well worth the effort... but there is more...

I get the impression you have read Vance Dickason's Loudspeaker Design Cookbook.  Honestly, I believe that all the work you describe above rarely is worth all the effort as the results may or may not be benificial, if even audible in a vehicle.  Read my sticky thread above called Comprehensive Front Stage Setup to see my reasoning.  Although the Cookbook is helpful to learn some aspects of audio, I don't believe it is very good for amatures.  It's easy to read some of the concepts and think they are much more important than they really are.

Here's a link to a great thread describing time alignment/phase alignment differences and their effects on staging.  You might find it interesting: http://forum.elitecaraudio.com/showthread.php?threadid=81356

spin06 wrote: Needless to say that in such a high calibre set-up as I have stated above should definately include - very high quality inter-connects 'without' touching or running close to Power cabling. Speaker leads running from the amplifier to all 4 corners should be of the exact same length,

I disagree.  High calibre RCA's are only good for looking pretty, while emptying your pocket book.  There may be some added induced noise rejection, but I believe that is moot as there wouldn't be any noise issues if the system was installed properly in the first place, with good equipment designed to reject noise.  As for the speaker wires, you will not receive any audible benifits from that.  Unfortunately there is a lot of voodoo marketing from wire companies misleading people into believing this.  I can only imagine the claims posted on their packaging if these companies were trying to sell ice cubes to eskimos.

Steven Kephart

Hello Stephen and thank you for your hospitality and warm welcome. Sorry for my lateness in responding I got caught up. To answer some of your questions (forgive me as I am not yet familiar with sending "Quotes" as you have done... so I will answer best I can. Q1) "I believe a tweeter should be matched to the woofer being used" A1) I refered to the driver system(s) as in KIT form ie: including matched Mid-woofers to tweeters - with the computer designed cross-overs within the kit. The only thing that is not purchased in the kit is the cabinets. My reference to 'woofers' was only the included 'mid-woofers' in the kit system. I am taking it for granted that readers will already have Sub woofers set up - in which case level adjustment should be all that is needed. Keep in mind here that the said kits are of exemplementry quality hence level only should be all that should be required. Q2) "I don't get why you are discussing soundstage with rear speakers" A2) The 'general' reader of this post will have a typical set-up ie: Pan - left to right (balance) and Fade - front to rear. In this system I specify here I am saying that there is ONLY Pan - left to right... both front speakers are 'Parelled' to the rears ie: FL to RL - and FR to RR. The 'staging' is all four speaker sets (the set being mid-woofer and tweeter) This way the centre of the car is where the centre of the stage should be. If 1 speaker is not connected then the stage is dramatically shifted. Q3) "We get our imaging cues from level differences for higher frequencies, not from the time domain" A3) as above stated Stephen this system is of exceptional quality, essentially readers of this post (should they buy the ScanSpeak driver kit) are getting a almost flawless system of remarkable flatness. Any nasties that may have been in the system originally (not due to bad driver matching but more over electrical disparancies) are null and viod to the ear. I can attest to the clean crisp and taught sound that this particular system evokes... it is a breathtaking listen. Let us keep in mind here that right now systems that are being employed by most everybody using 'car speakers' must electronically 'tune-out' those mis-matches. Boston make (arguably) one of the best set of 'car Hi-Fi' splits... the comparrison between the ScanSpeak Revelator system and any Boston driver is a one horse race! To verify my point here... a listen to a pair of Solist Reference speakers (Madisound stock these) will have you converted. Trully sensational. Q4) "Can you explain why having the tweeter on top will help?" A4) Because these drivers are so revealing this Off-set or time-aligned array (setting the tweeter back) is a tweek that shows just HOW revealing they are. Time-aligning is almost never done in 'car audio' set-ups... yet it is a tweek that is done now by many high end speaker companies. Again.... we are not using 'car drivers' in this system. Q5) The 'Cookbook' A5)lol... yes I think that almost anybody who is into audio systems has read this. I do not make any particular reference to Mr. Dickasons book but I do remember reading it. Q6) "High calibre RCA's are only good for looking pretty" A6) I must disagree with you Stephen. I have heard with my own ears a difference with quality connects. Although do not get me wrong here... I was not suggesting that any reader of this post spend $000's on wiring and gold connectors... that IS futile and in my estimation rediculous... my reference was to OFC wiring with good gold connectors that can be bought for $40-50. In regards to speaker Lead length (my comment saying the leads should be exactly the same length)... I agree with you Stephen that in an average set-up beit home or car that 'tweak' is somewhat non existant... yet this is no ordinary beasty - I have proven this personally with a system utilizing the 'Revelator' tweeter. I purposely cut short the left hand side of a simple set of OFC (to bare wire on binding posts) leads by 2 feet. The right side channel stayed untouched. I then proceeded to play a few well known (to me) test records (yes vinyl... lol) I could not hear any diference whatsoever. It then came to me to try an old trick whereby you put on a set of headphones and get the volumes between the cans and the speakers at the same level (or there abouts). By moving one ear piece away from my ear one at a time revealed that there was a very slight delay in the speaker with the untouched OFC cable... thus proving to me that there was indeed a need for 'same length' cabling. In a system of this extrodinary openness and its revealing nature you will hear things in your music that you listen to everyday.... that you would have never heard before. Again please forgive my slow response to your reply post stephen. I hope this answers your above questions. STEVEFutureFone Acoustic

I must also add to readers that listening to quality audio is a personal thing... we all have our own thoughts on good sound. So please do not think that I am disputing feedback comments... simply my thoughts and personal findings. I must add here though that the above system in many people who have auditioned it rave about it. STEVEFutureFone Acoustic