Just did some playing around with graphing mid-bass drivers in Bassbox pro. I was curious to see if there were any typical patterns associated with mid-bass performance, as well as how mid-bass performance was effected by different characteristics (cone area, motor structure, etc).

I plotted as many mid-bass drivers as I could find (didn't get around to Polk or Scanspeak) using two different volumes - once at 9.5L (to represent a typical custom door enclosure) and one at 25L (to represent a tyical car door). I then took one measurement at 0dB (to represent what the speaker can play flat down to) and another measurement at 60hz (to measure speaker intesity at this popular crossover point).

For reasons of consistency, I didn't factor cabin gain into the equation at this stage.

After measure a list of 16 different drivers from brands including Rainbow, Dynaudio, Digital Designs, Seas, Oz Audio, Focal and Eton - my end results were quite interesting.

Of all 16 drivers, there were only 5 which showed to be seriously capable as a dedicated mid-bass driver. These 5 all played down low enough to be able to make some serious use of cabin gain in the real world, and even without cabin gain they played low enough to be usable as a mid-bass driver. Taking an average of all the 6.5" and 7" drivers showed that the typical 6.5" / 7" mid-bass driver will play flat down to only 142hz before beginning to gradually roll off. Even in a 25L enclosure, the average 6.5 or 7" driver is down by as much as 5.5dB at 60hz...too great a degree for cabin gain to help significantly.

The only 5 drivers that performed sufficiently, in no particular order were:
* Rainbow W175 Power (7")
* Dynaudio MW180 (10")
* Digital Designs DDW6.5 (6.5")
* Focal Utopia W3 Be (6.5")
* Seas Excel W26FX-001 (10")

All of these drivers were able to play flat to about 80hz (give or take) before rolling off, and each was able to play down to 60hz at -3dB or better - which puts them in a position to be potentially aided by cabin gain.

I understand this is measured using a computer program, and may not be 100% perfectly comparable to performance in the real world - however if you take a look at the measurements for the dynaudio MW160 it's actually very similar to what Dynaudio shows in their frequency response graphs and a good look at all of the drivers shows some degree of consistency.

Alas either way it's something interesting to look at, so I decided I'd post it up here for you guys to have a play with.

Below are the results of the drivers tested:

Rainbow W175 Power (7")
9.5L: 0dB @ 70hz, -2.1dB @ 60hz
25L: 0dB @ 100hz, -1.43dB @ 60hz

Rainbow W175 Platinum (7")
9.5L: 0dB @ 150hz, -14dB @ 60hz
25L: 0dB @ 280hz, -10dB @ 60hz

Rainbow Profi Vanadium Kick (6.5")
9.5L: 0dB @ 120hz, -9dB @ 60hz
25L: 0dB @140hz, -6.89dB @ 60hz

Rainbow Profi Vanadium (6.5")
9.5L: 0dB @ 158hz, -8dB @60hz
25L: 0dB @ 250hz, -6.6dB @60hz

Dynaudio MW160 (7")
9.5L: 0dB @ 180hz, -6.5dB @60hz
25L: 0dB @ 220hz, -5.9dB @60hz

Dynaudio MW170 (8")
9.5L: 0dB @ 90hz, -5.3dB @60hz
25L: 0dB @105hz, -3.3dB @ 60hz

Dynaudio MW180 (10")
9.5L: 0dB @78hz, -4.68dB @60hz
25L: 0dB @72hz, -1.5dB @60hz

Diamond Audio S600 Hex (6.5")
9.5L:137hz @0dB, -8.2dB @60hz
25L: 370hz @0dB, -5.9dB @60hz

Digital Designs DDW6.5 (6.5")
9.5L: 0dB @82hz, -2.1dB @60hz
25L: 0dB @100h, -2dB @60hz

Eton Adventure A1-160 (6.5")
9.5L: 0dB @228hz, -8dB @60hz
25L: 0dB @325hz, -6.9dB @60hz

Focal 6 K3P (6.5")
9.5L: 0dB @150hz, -7.9dB @60hz
25L: 0dB @200hz, -6.7dB @60hz

Focal Utopia W3 Be (6.5")
9.5L: 0dB @84hz, -4.2db @60hz
25L: 0dB @87hz, -2.9dB @60hz

Oz Audio OZ-180(6.5" - from Matrix Elite line)
9.5L: 0dB @117hz, -6.5dB @60hz
25L: 0dB @154hz, -5dB @60hz

Seas Excell W18E-001 (7")
9.5L: 0dB @230hz, -5.6dB @60hz
25L: 0dB @200hz, -5.2dB @60hz

Seas Excell W22EX-001 (8")
9.5L: 0dB @100hz, -5.6dB @60hz
25L: 0dB @140hz, -3.8dB @60hz

Seas Excell W26FX-001 (10")
9.5L: 0dB @ 78hz, -4.7dB @60hz
25L: 0dB @73hz, -1.2dB @60hz

Peerless SLS213 /830667 (8")
9.5L: 0dB @72hz, -1.5dB @60hz
25L: 0dB @35hz, +0.5dB@60hz

TANG BAND W8-740C
9.5L: 0dB @200hz, -4.9dB @60hz
25L: 0dB @200hz, -5.1dB @60hz

Your tests are slightly wrong. You should set a benchmark of say 100db and then say at 60hz this woofer is 78db, 84db etc.

Some woofers may have a lighter cone and a higher sensitivity so the volume will drop off as the frequencies become lower, however as the drop originated at a much higher volume it may still have louder midbass than the others.

Also I wouldn't use 60hz for these tests realistically you would be better off using 80hz or better yet 100hz as most of the initial kick is 100hz or higher. Most internet sources dont even regard 60hz as midbass. In my opinion midbass is between 60 and 200hz. So picking the lowest frequency would not be as accurate as using a frequency somewhere in the middle.



Finally i wouldn't use 9.5litres as that is way too small. To reflect a leaky car door you'd be much better off putting in a value of 100 litres. Though 25litres would be fine as it wont change much.

Also try putting in the Eminence Beta 10A's into your equations. Its volume at all frequencies should be greater than the rest.

The results should be much better as it will give an even comparison between drivers running off a single watt of power. Some drivers may handle more power though which may allow them to become louder.

I'll throw in a couple extra drivers for you to model,

SLS 830667 Peerless 8" Paper Cone Woofer
Coated Paper cone
Rubber surround
Rigid stamped frame
Ventilated raised spider
Bumped back plate
Shorting ring
213.5mm flange
178mm cut out hole size
100mm depth

Nominal Impedance 8 ohm
Re 5.9 ohm
Fs 36.5 Hz
Sensitivity 87.2 dB
Qms 7.8
Qes 0.59
Qts 0.54
Vas 33.1 liters
Bl 8.3 Tm
Mms 33g
Cms 0.57 mm/N
Le 2.1mH
VC diameter 39mm
X-max 8.5mm

and

TANG BAND W8-740C
Specifications: Power Handling: 150 watts RMS/300 watts max
VCdia: 2"
Impedance: 4 ohms
Frequency range: 28-1,000 Hz
Fs: 28 Hz
SPL: 84 dB 2.83V/1m
Vas: .81 cu. ft.
Qms: 10.53
Qes: .30
Qts: .30
Xmax: 12mm
Dimensions: A: 8-1/4", B: 7-1/4", C: 4-3/4"

Both of these drivers retail for about $50-$60 USD..

Test here is designed around SQ, and the majority of SQ competitors I know of use cross-over points below 80hz.

Rather then using this to represent optimal mid-bass cut-off point, I'm aiming to representing the cross-over opints most users would stick with.

As for dB, I don't understand the difference it makes? If you set the benchmark as 100dB and you measure 97dB, or you set the benchmark at 0dB and the measurement is at -3dB...what's the difference?

Whether one driver can produce more mid-bass then another is (IMO) entirely irrelevant for SQ purposes. To me the important part is which driver can produce the most ballanced and lowest usable response. In an SQ system the important thing is comparative output (being at the same level throughout) rather then outright level (i.e. how loud your mid-bass can go). Outright level is more an issue of sensitivity and power handling, and will only come into account in an SQ system at extremely high volume levels (assume the system is well balanced).

Lower crossover points help with overall detail as well as with locality of bass (i.e. getting bass in front effectively), and so low crossover points do have their place in SQ installations..

Big reason I did this is because a lot people competing in SQ run crossover points down to 65hz, 50hz and in some cases even 40hz using 6.5" drivers, so what I'm trying to illustrate here is the ability for a 6.5" driver to perform suitably under those circumstances.

Not fighting with you or anything, but to me (cabin gain aside) this method gives a better undrestanding of mid-bass performance in the situation most people run with.

You must also take into account that these responses assume a properly sealed enclosure, and that no car door does truly operate as a proper enclosure.. that means the actual real world results will actually lilkely get worse then those indicated before they'll get any better.

Of course the other issue is due to the fact that most car doors arent perfectly sealed and the fact that in a lot of cars the volume of the door is alot larger then the Vas of the driver which I'm not 100% but I was under the belief that in a sealed or close to sealed enclosure, once you have an enclosure larger then VAS it is technically working in IB.

Then of course since you have modelled these in enclosures your results won't reflect anywhere near the actual ability, since many of these drivers are designed for IB, the Rainbow Reference is like this aparently placed in a sealed 41litre enclosure it sounded terrible, but once placed into a leaky car door (so IB) they sounded incredible excellent midbass etc...

So I think you should be modelling around your 9.5L (pod size) and then probably a IB model would be more reflective of real world conditions.

Not having a go at you just trying to add some of my (what I think is correct) knowledge to the table....

Luke

Drivers added!

Infinite baffle is a little harder to model, not sure how to go about that. Another thing is that IB is essentially free air, and even in a car door that isn't entirely sealed, it's still not entirely free air either.

I think IB would be better represented by taking the drivers and sitting it on the floor of the car without a box, in which case i'd be very surprised of the mid-bass response came close to what it is in a door.

With the Rainbow Reference driver, It's difficult to compare the enclosure performance compared to door performance. If they tested it in an enclosure as large as 41L, then where did they fit that enclosure? Sure not in the cabin of the car, and if so they would have been compromised by possible positioning which would naturally impact on performance.

Only way I could imagine in by placing it in a 41L enclosure outside the car, and then comparing that to in-door mounting inside the car. If that was the case, it'd quite possibly be an unsuitable comparison. The Reference a moce compact (yet more powerful) neodymium magnet structure for it's magnets, so can get huge strength without the bulk of the double stacked deal on the Power unit. Because of this beeffy motor structure, I'd say the Reference probably stacks up pretty well to the Power in bottom end performance and if so it'd defiantely be effected by in-car gain. That means a 41L 'external' vs door 'internal' test would lack consistency. Either way, I can't see how that type of test could have been peformed consistently.

P.s. does anyone know the TS specs of the Rainbow Reference driver? I'd be very interested in checking it's performance against the W175 Power... future upgrade maybe?

The Peerless is definitely a good performer, and cheap and actually extremely well built, and are quite capable of outperforming many drivers several times there price upto about 500hz...

Luke

Is it a mid-bass or a subwoofer? Curious because if it's a sub, distortion levels may lead it unsuitable above 150hz (even if response graph shows that it works).

Two biggest surprises for me were:
1) The Rainbow 7" Power outperforming the 10" Dynaudio driver, and almost matching the Seas 10".
2) The performance of the DDW6.5. Extremely impressive results for a 6.5" mid-bass driver, especially when you consider the price.

Midbass, well actually it's classed as a woofer, designed for low end through to lower midrange for home audio so about 40-50hz up to 500hz etc... but it is a treated cone so it will handle car doors reasonably well.

Luke

Just read they are releasing a 6.5" SLS end of July here are the specs http://www.tymphany.com/datasheet/printview.php?id=355

http://www.diymobileaudio.com/forum/showth...ht=peerless+sls

If you go there you can see all the independent distortion analysis and alot more other graphs etc...

In case you didn't realise if you have the crossover point set at 80hz, it is actually at -3db at this point. The crossover curve starts well above or below this frequency. As you like to give the starting frequency at which the midbass drops off then you should use the frequency at which the crossover starts to drop, this would be much higher than the crossover frequency. So 60hz is not correct at all, even for a SQ system. 100hz would be much more accurate. If you had a driver that put out alot of midbass at 60hz but none at 100hz, then it would appear to have less midbass than a driver that put out alot of midbass at 100hz but none at 60hz.



It makes a very big difference. You have set a seperate benchmark for every driver. The benchmark is the highest sensitivity at any frequency for each driver. You cannot compare drivers unless you set a benchmark and compare every woofer against it.

As you are stugling to understand i will give you an example using two drivers.

Driver A has a 96db sensitivty at 200hz yet at 60hz its sensitivity is 85db.. according to your analysis it would be -16db down at 60hz.

Driver B might have a sensitivity of 88db at 250hz yet at 60hz it may have a sensitivity of 80db.Your result will then give it -8db at 60hz.

According to your analysis Driver B will have nearly twice as much midbass. As its result is 8db instread of 16db or twice as much.. Yet driver A is actually 5db louder at 60hz.

Also the answers of 8db and 16db make one item appear to be twice as loud. This is similar to changing the scale of a graph to make the difference between two bars much greater. 85db and 80db will allow the average user to see a small difference between the two. Yet 8db and 16db can be misinterpreted to be twice the difference.

So your analysis proves nothing that will help SQ other than the fact some speakers frequency response aren't flat.

what about distortion, and upper frequecy limits - that would be interesting to see which drivers (from a 2-way set) will actually perform well at the factory passive crossover frequency - usually 2.8 to 5.6kHz (depending on tweeter used).

I know for sure that I have not heard a 6 or 7 inch "car audio" driver which is very good at 2kHz....

IB graphing would be when u increase the Ltrs of the enclosure until the graphs stop changing,thats not hard to do..........cors

You cant test that on a computer program im afraid.



Usually upper frequency response is very good if the speaker is on axis. As the speaker moves off axis the upper frequencies decrease. Same applies to most tweeters.

Im not sure exactly, but if an enclosure exceeds the drivers VAS and essentially becomes free air, why do we get almost no midbass performance from a 6.5in driver that is not sealed to a door, compared to amazing response from the same woofer correctly sealed, regardless of door size?
When testing the axis of my door pods during construction, I had them mounted to the skeleton frame, and had almost zero midbass response, almost rendering the tested axis irrelevant, sure it had midrange, but no midbass at all.
All sealed up and deadened, it had bucketloads, enough that it needs to be EQ'd down to achieve linearity.

I understand that a door is a leaky enclosure, but how leaky? are all doors different? some doors seal quite well, and others are just terrible, requiring a lot of work to get them acceptable. im thinking that the almost endless variants render most PC simulations almost useless unless some sort of fixed benchmark can be used.

Is it possible that a driver that models nicely in bass box pro may actually perform worse than an inferior driver modelled under the same conditions, purely due to the size, type and level of sealing a particular door has?
Im thinking its possible that some manufacturers go for good modelling stats and others are more concerned with real world applications, such as leaky door mounting, and can actually be better for it?

Is there ANY way to simulate a slightly leaky door enclosure using the correct size in litres, in bass box pro? I'd love to give that a go using my VT door as a guinea pig, could save ME a lot of confusion when I upgrade, and Im currently only using bass box for sub box and home speaker modelling and am interested in this whole midbass debate..

because the back waves aren't separated from the front waves. so its not even in IB.

Would be interesting to see the results of the long throw version

Yeah your not wrong.



Upper frequency response becomes a problem as the frequency length starts to be close or smaller than the diameter of the cone (as already mentioned)



But there are "worse" problems than this. Cone model distortion is a combination of cone apex angle (how shallow or steep the cone angle) the material used (internal dampening) and MOST importantly the termination of the cone. For a dome it is the centre apex that must deal with axis modal lines, and this is the reason of the need to to have the dome material so flexible. With a cone drivers the termination of the cone is determined by the surround. In this case we have an open termination with decoupler (surround), whereas with a dome it is a closed termination with the dome material providing the dampening (The reason why a dome needs to be off axis, is on axis the modal distortion is clearly audible.)



On a large cone radiating driver the modal lines accelerate from the apex (centre) to the rim. (surround) The surround is therefore responsible for taming this activity, however like all things they have there limitations. In this case the surround has its own resonate frequency, and when the driver plays this frequency, the modal lines are reflected back towards the centre (like a closed termination). This is called "surround step response" All cone drivers have it, and with large cones it is quite low frequency, in this case with 6.5 " drivers and up it is..2000 Hz.



Well done Pulse-r, your auditory system is "bang on".



Point

Two way systems suk in a car. (unless your deaf)



As an aside, the reason for fakes sounding so bad compared to the originals?



In theory they are a duplicate, so where do they go wrong?

Well mainly in the voice coil and BL curves, (The use of round wire rather than flat wire on the coils leaves air pocket gaps in the voice coils etc)



But the other biggy?

The surround. Yep this is an art form, in getting it right.

I'm not entirely certain on this one, free-air is technically very different to IB, I might need Abmolech or some others to help explain it better.

But free air is just sitting a driver on the floor etc or even suspending it, whereas IB requires the driver to be mounted to a baffle and for car audio applications really refers to placing the driver on a baffle of a excessively large enclosure boot, car door etc...

There is a lot of science put into baffle construction for home audio... http://www.jamo.com/Default.aspx?ID=2250&a...ProductID=17862 those Dipolar Jamo's are essentially some drivers mounted to a baffle with no enclosure other then the room there in, but they have amazing low end reproduction from the reviews I've seen.

Anyway maybe Abmolech or some else can explain this it in a better way then my half ramblings...

Luke

They didnt put the Reference driver on the Klippel but they have done the Platinum (I'm not sure where that sits in Rainbows lineup) , link also has measurements for Alpine f1 and also the Peerless Exclusive.

Well that really depends on what slope you use, doesn't it?



If you take one look at the graphs, the data actually represents the graphs pretty accurately. In the case of speakers that start to fall off at very high points (say, 400hz) rather then use the actual 0dB point exactly, I've actually used the point where the driver starts to 'noticably' roll off (sometimes this was actually 0.5dB) to give a more realistic indication of there the roll off point begins.

Either way, if a driver is outputting 8dB less at 60hz then it is at 120hz, that driver is far from optimal for midbass duties, correct?

On the other hand, a driver that is 2dB down at 60hz compared to what it is at 120hz would typically be much more suitable as a mid-bass driver. If it can be at only -2 at 60hz, then you can bet it's close to flat at 80hz.

So actually it still says plenty.

However, I'll try to change the scale if I can and re-do the readings with the other scale as well if you like.. still don't get the point though. Personally I don't care how much dB down a speaker looks at 60hz compared to another speaker, I care how much a speaker is down at 60hz compared to itself at 80hz, 120hz or 150hz.

That's what I'm trying to test. Checking at which point the speaker measures 0dB, and then seeing the intensity at 60hz, essentially gives a good indication of how heavilly the speaker drops off down low.

It all comes down to the factor of human hearing called frequency masking (from memory, that's the term). If a particular frequency is domant over another in intensity, then out ears can e tricked tricked into beliving that the frequency with the lower intensity is not present - even though it may still be fairly high in intensity.

For example, a speaker that is at 0dB at 100hz and then -8dB at 60hz obviously drops of far more steeply then a speaker that is at 0db at 100hz and -2dB at 60hz. In the case of the second speaker 60hz is only down by 2dB which is not a huge amount, and so our ears would easilly pick up that frequencies presence. In the case of the first speaker, 60hz is down by 8dB...this is a significant drop from 100hz and so in comparison, out ears would be tricked into hearing a lack or sound at 60hz. It doesn't matter of that 60hz is at 94dB, 100dB or 130dB, as long as 100hz is significantly higher in intensity (from the mid-bass) and 0-40hz are significantly higher (from the sub) then the comparatively lower intensity signal at 60hz would appear to be missing.

Of coruse you also need to factor in human hearing sensitivity at different frequencies also, but still the general rule applies.

So at the end of that day it's not the actual intensity of the signal at that frequency that matters in a SQ system (want more intensity, increase the power), it's the intensity of the speaker at that frequency compared to the same speakers relative intensity at other frequencies that matters.

Unless you want to argue tha more mid-bass is always better and 'you can never have too much mid-bass' like some suggest, but personally i think that statement holds no weight in any serious pure SQ discussion.

If you wish to get technical an INFINITE baffle is a baffle without end.



So the baffle size is sufficient, that using a larger one would be no difference to the loading (steradians) or the baffle has no end , that is, it is infinite.



A sealed enclosure therefore qualifies as the REAL infinite baffle.





Warning boring rant from abmolech follows...



I did warn you stop now.



A circle is without end, and the symbol for infinity is two adjacent circles (the figure 8 on its side, infact 8 represents infinity) Ouroboros is a snake eating its tail, in the figure of an 8. Circle is where we get "sir" from (the egg) IE generations, or in tennis luv the egg = zero the circle.



Not my fault.



Great post muzzy66



Credits to you.

excellent work muzzy. I'd be very intrested to see how a 18W revelator goes.

DD have been building and developing the W6.5 for over 20 years, it's one of the first speakers they ever made. It was originally developed for their studio monitors.

We used to have an LT (long throw) version with a bigger coil, it only played up to around 1k. The new version of the W6.5 manages the same throw and low end extension, but plays happily up pask 3.5k.

I use the W6.5s in my home cinema matched to Scanspeak Revelator tweeters, with custom passives made from Solen Hepta-litz inductors and caps. It's a sweet sounding combo.

Brad's Colt (Car Tunez) runs a pair of W6.5 in each door, it will play bass tracks and sweeps full range at serious levels, ask anyone who has heard (felt) it.

In Brad's 323, a single door mounted pair of the older W6.5s hit over 130dB on Termlab at around 70Hz. Serious output for a free air mounted 6.5".

Phil

WHy even bother with cad. grab a speaker and mess with it in real world. I use my 8" dyns in abox of about 8-10 litres. They work a treat. I have midbass that sounds ok. I read a great article inCar Audio and Electronics about how the real key to getting great midbass was to used a sealed enclosure, even if its a lot smaller than you would use in another apllication.

I have seen many home audio speakers that use 6's or 8's that get incredibly low by using great box design. We dont have that luxury so we use dedicated subs to get a solid bottom end, and if we get the midbass right too then we can have true hi fidelity in the car, despite what many home audiophiles may believe, it can be done.

As a midbass is all about kick, using a small box only helps to emphasise this. As you dont need to the midbass to get down to 20 Hz you dont need the perfect box, but I believe you do need a box or more corectly an enclosure. Sealing the midbass driver is about the smartest thing you can do.

anyway have a play with real speakers, in a real car(you will learn more) and then go to the control panel on your PC and select remove program for your cad. I havent used a CAD program for years. Lifes to short IMO to let a PC tell you how to build a box, and how it sounds. I prefer my ears.
peace
Cyberpunky

I feel there is a misconception about baffle/baffles.Whatever is written before in dictionaries and science books is of no concern to me.
A infinate baffle means that there is no baffle being registered on the test, as such it is infinate in size and un measurable. Our test speaker is a 10" driver.
Here is questions for anyone to prove my idea> if a speaker is in mid air and has no attachments, will it measure a baffle response on a test?
If a speaker has a mounting plate(front plate) thats only as wide as the screws that go into it, will it measure a baffle response on a test ?
If a speaker has a mounting plate(front plate) of a 12" diameter(thats 2" wider than the speaker), will it measure a baffle response on a test?
What about a speaker with a face plate of 20" diameter or more, will it measure a baffle response on a test ?

conclusion~
As soon as the test shows a measurable baffle difference it becomes finite, and the baffle/face plate becomes a limiting factor. Therefore if a face plate changes the test and a measurable difference is noticed then that face plate is a baffle, but if the face plate does not make a measurable difference on a test then that face plate is NOT a baffle.

Anyway we were discussing baffles the other night and i thought i would explain what i was trying to say here. A face plate is not a baffle if its unmeasurable, please continue ablotech ........cors

im with bruce here.

of what i have listen to on that list the Eton and the OZ have been 2 of my fave midbass speakers.

some of the other top ones have been a little eh

your eye's mean nothing when you can only hear the speaker, f*** the graphs off and just listen.

I like Baffles with a dolop of ice cream .............sorry.



Muzz could you run a test on the Hybrid Audio L6 please:

http://www.hybrid-audio.com/downloads.htm

I'd be curious to see how it compares.

Ill have to agree with Bruce and Fudd here. My dyns have never 'graphed' well, but I am honestly yet to hear a midbass that sounds better.

You're problem here is you have defined, from the start, what you think makes a good midbass. That obviously being low end extension. I fail to understand how someone of your knowledge can make such a ignorant statement? No offence muzzy, cause I do respect you, but thats just narrow minded.

Midbass is midbass, and subbass is subbass. Low end extension is only achieved with a motor that has a compliant suspension, and couples well with a good enclosure. Usually that means a low Qts unit, which to be frightfully honest, doesnt usually produce good midbass attack/decay. To have an 'accurate' midbass (personal preference defines what is good or not) a higher Qts is recommended (0.5-0.7), along with a stifffer suspension and great Linear Xmax (to keep that Bl curve as flat as possible).

Also, if the inductance is too high, and the suspension too soft, then the speakers ability to reproduce the higher frequencies will be severely compromised. Depending on the midrange you select, the midbass's abilities to reproduce up that high will be tested. There is no use buying a Focal KBE if you have a dome midrange, for example. Or maybe you have a 5", that can play down to around 100Hz, and is used as your midrange. Coupling it with a sub (10-12") will eliminate the need for a 7-8" midbass altogether. Adding one in there will just be useless. (Just take note that your programs DONT model the response of anything over ~100Hz).

We are always recommending to others to listen to a front stage before purchasing, and yet we already know that different tests and graphs can tell us the same as your's does. You cannot limit the scope of selection by using a limited range of graphs. If you use the Frequency Response graphs, Impulse Response, BL curves, Waterfall curves etc. then it presents a bigger and better picture, but a single T/S spec analysis in Bassbox really doesnt cut it

do graphs show you how a speaker actually sounds???

or will you just believe a speaker cant do something cos graphs didnt say so???

there are so many uncontrolable variables that graphs miss that it can never be a good way to judge a midbass, or any driver,


ears never lie though, if it sounds good, it sounds good wether graphs say so or not...



to throw a spanner in the cogs, what if your midbass didnt have to play to 60hz, what if you had a sub that played very accurately and flat to 80 hz??? or even 100 hz???

if this is to prove low end extension then great, but if its to prove how good a MIDbass is, then its a tad off, and real world may be a better guide...

If this was the case stereo would never work.

Graphs are not meaningless, they can tell you something of a drivers expected capabilities. If the response is poor at this level it is unlikely to get better.



The reality is a driver is a high distortion device, and some distortion is more pleasant than others. The dynaudio series epitomises this.

i think what abmolech is saying, some can read graphs and understand them others cannot. graphs show exactly what they show, nothing more and nothing less. im sure muzzy isn't saying that midbass drivers sound good because of the linearity, he's just showing some strengths and weaknesses between drivers.



and if ANYBODY here who has been saying 'blah blah blah, get speakers and listen blah blah blah' i want YOU to go out and BUY all 10 or so drivers that pete has modelled. im sure you guys obviously have a lazy 5-10k laying around doing nothing. THEN ur comments will be listened to will have some weight. all u guys are doing is dumping on somebody elses hard work. so if u r going to continue with that line of thinking then STFU. to many pricks like that in this thread. why dont i come round to ur cars and pick at all ur hard work?

Actually with the right graphs you can tell how a speaker will sound, they can't really show tonality, but they can show freq range, whether they are likely to hit tighter, snappier, weightier, strong midrange, weak midrange, and so on and so on.

The trick is to know what a speaker you like the sound of, how it models in certain measurements and graphs so that you will know what kind of drivers to look for when shopping without listening.

You can only say graphs have no meaning when you don't understand how certain things on graphs correlate to how a speaker will sound.

I used to be of the same opinion "what can a graph tell me", till I did a bit of learning as to what a graph etc.. actually can tell you and it's a lot.

Sure there will always be anomalies but they are fewer more so then many.

In either case I'd like to understand alot more of the graphs I see around the place .

One of the main reasons for my increasing interest in these kind of things, because there is a hell of a lot of great drivers out there that can be purchased from suppliers for reasonable cost that can easily outperform the driver in your $1000 component set.... A couple of good example's CDT are widely known to use slightly modified Vifa drivers (in most cases they sound barely different) and the Vifa equivelant can be purchased for about 1/3 the cost. The Alpine type X tweeter can be purchased through a supplier for $38 USD a pair, thats right your $600-$700 splits use a tweeter worth $25 aussie each. Peerless and Seas make lots of drivers that will enable you to throw together a front stage for a few hundred dollars that will outperform the equivelant Retail components worth 2-3 times the amount. But how are you gonna have any idea how these drivers sound (which in most cases you can't listen to anywhere). By Reading and Understanding these graphs, plots and measurements...


But don't get me wrong graphs and measurements arent the be all and end all, but all these graphs and measurements can really help point you in the right place and turn what could be a rather long and expensive search for the right speaker for you into a shorter and cheaper one, sure you probably still won't get it right the first time but it will help.

there u go, straight from the horses mouth. so next time the keyboard warriors want to have a dig at someones hard work with non-constructive critisicm (there is constructive critisim in this thread and this isn't aimed at those ppl who have contributed) at least read the thread.

its pretty clear that all muzzy is trying to show is how ppl are often crossing to low for their drivers to be nice and flat. i dont see ANYWHERE where muzzy is trying to prove anything else. so fo all the forum trolls out there, keep trolling. u look like real fvcken silly.

There are lots of subs that can play flat well above 100hz, I know a couple that will go to a 1000hz flat (and to steal a quote from abmolech) "would you want to listen to it though" and the answer is No there are plenty of drivers that play flat well outside there recommended freq ranges but being able to play flat doesnt mean it will sound good at those freq ranges, this is where a lot of other graphs and plots help out.

its all a healthy discussion,

i was hinting at what was said about tonality, sure graphs can show you distortion, decay, etc...

but, i wouldnt choose a speaker off looking at the graphs,,


calm down steve, its a frickin internet forum for fks sake, its all tongue in cheek, and its all part of a healthy discussion...




just cos a speaker wont play flat to 60 hz, doesnt mean there is no point in crossing it that low though,

i respect the fact that muzzy is taking the time to do this as its almost a public service,

but graphs arent all there is to audio, there is also sound, remember??

sry, but i dont think it is all just healthy discussion. i know ur a reasonable fellow, but theres some in this thread who are simply not reading the thread.



this here is the crux. i dont think pete has enough dosh to go out and buy 16 high end drivers. hell, i dont think anybody here has that kind of money to spend on a simple comparison.

all pete is trying to show is how low some drivers can play. nothing more nothing less. i dont think a single person here has even commented on that fact with his findings with his modelling. some here have been trying to improve petes method, which is fine, but comments such as those above are just not on. its demeaning and thoughtless.

why dont we have technical discussions in these forums? for this exact reason. give the guy a chance instead of ragging on him.

EDIT: i dont mean to single you out rob either. its simply a trend (and im not the first to admit or comment on it) that needs to be discouraged. ppl like pete need to be encouraged not ragged on every time they try to show a simple fact.



crap, u'd think these forums are allergic to scientific backing of opinions. every other forum i visit they WANT these sort of factual evidence. here its the reverse

one thing is for sure , modeling speakers before your own "in car tests" can show u how a graph can be misleading or maybe show u some characteristics that may have a predictability,but u still have to do your own testing.
So in reality the graph is not a must but can be used before or after your tests.
Im exploring the idea of "Bass Surround" and like charlie mentioned the fronts dont have to play super low.........cors

the main problem with manufacturer's graphs, is the drivers are measured free-air, not in an enclosure of any type.

dyn MW162's look terrible on paper, and in the above tests, but I have had no trouble using them in my doors down to 56Hz/18dB (50Hz was too low), and crossing the sub at 63Hz/24dB. This seems to work quite well for me as I have a cancellation issue in the midbass drivers at 60Hz, so the sub happily picks this up and smooths everything out.

I'm all for trying different things, and these are the 3rd set of midbass I've had (all 6" or so) and I'm happy with the sound.

On the topic of using graphs (for tuning EQ) I use them cos I need them, but later-on with more experience I may be able to do away with them.

Juls and Redlined have both had a go at tuning my system at different times, and were able to correctly identify the frequencies that needed adjustment (according to my graphs...ironic I know LOL) but I can't do that cos I'm just a beginner. With my graphs, generally if it looks good it sounds good, although I don't just trust what I see. I listen, make adustments and take more graphs to make sure the response is smooth. But basically I reckon each to his own.

And on the topic of manufacturer's graphs, you have to take things with a grain of salt. Take motorcyles for example, can you ever believe Honda's dry weights? Nah you always add about 20kg. But thier claimed dry weight is a 'guide'. It's something to go by while sizing up what you want to buy. If you hear that a certain manufacturer's claims are exaggerated you take that into consideration when making comparisons

I haven't read the entire thread word for word so I hope I'm not repeating what someone has already said


cheers

You should always tune by ear.

Phil