# Understanding what speaker specs are important for midbass



## james2266 (Sep 24, 2009)

I have talked to several different members here and have gotten some very useful info but I guess I want more and clarity on a few things. I am under the impression that fs, xmax and qts are the most important factors for midbass reproduction. From what I have learned you want as low fs as you can and as much xmax as you can. Totally makes sense for a subwoofer but how important is it for midbass. Is there a point where moving lower in fs makes no improvement or over a certain xmax makes no improvement. Also with qts I have been told that a high qts is important for midbass output if installed ib in a door as mine are. How high is high? Is there a perfect number to look for in any/all of these parameters for a midbass installed ib in a door? Does the size/shape of the door change the ideal numbers too (if there is an ideal number). Also, are there other speaker specs that are important for midbass production that I am unaware of? 

I really want to know what driver is best for me and am seriously considering going with raw home drivers as money is tight and I have been told there is way more bang for buck with them. My recent addition of a Scanspeak 10f is what really has me considering this now. I am talking strictly midbass here too as I am running 3 way. My midbass currently covers 60 Hz to 250 Hz 24 db butterworth.


----------



## diatribe (Aug 11, 2008)

Generally low fs, large xmax and high qts is desirable in IB door speakers. But you can get around some of these factors with a few tricks.

You don't have to have very low fs in order to hear good midbass in doors. Most speakers can be EQ'ed to sound just fine with a little tweaking. The lower you plan on going the more xmax you are going to need, but unless you are installing subwoofers, you're going to high pass around 100Hz.

I look for speakers with a qts around .5 and up when IB in the doors. But there is a way around that.

Here is an interesting article that Adire printed a while back on variable qts with multiple voice coil drivers. This can allow you to use a wider array of speakers in IB.

http://web.archive.org/web/20060105112923/http://www.adireaudio.com/Files/TechPapers/RDOOperation.pdf


----------



## james2266 (Sep 24, 2009)

diatribe said:


> Generally low fs, large xmax and high qts is desirable in IB door speakers. But you can get around some of these factors with a few tricks.
> 
> You don't have to have very low fs in order to hear good midbass in doors. Most speakers can be EQ'ed to sound just fine with a little tweaking. The lower you plan on going the more xmax you are going to need, but unless you are installing subwoofers, you're going to high pass around 100Hz.
> 
> ...


Thanks for the link but I am not talking subwoofers here and don't have a dual vc sub in my setup currently. I will keep it in mind if I ever do down the road however.

Ok, so you say low fs, high qts and high xmax. I have heard all of this before but 'what is high'? You mentioned .5 and up for a qts and I thank you for that. That was the number I think I heard before. Is there a perfect qts to aim for or just as high as you can get? Is there a 'too high'? 

I think I finally figured out how xmax is reported by manufacturers. I was confused as it seems there are two different methods of reporting it. Some just list a mm measurement like my current Hertz driver - 6 mm. Other companies list it as maximum linear excursion like Dynaudio 6 mm and still others list it as +/- like Morel +/-4.25mm and what makes it worse for Morel is they list off maximum linear excursion which is in brackets and looks to be twice the number. I am assuming if only a single number is given for xmax like my Hertz it is +/- but if it is listed as maximum linear excursion then it is actually reporting 2x xmax? In Morel's case, it is the +/- number that is the true xmax. Do I have this right or am I completely wrong here? I want to make sure that I am putting in the right number into winisd for doing calculations. Also, what is the best enclosure to use to simulate ib in a door with winisd or is it even possible?


----------



## minbari (Mar 3, 2011)

I disagree with the low FS requirement. some of the best midbass have FS in the 70-80 hz range. you dont need a 6.5" that has an FS of 40 hz if you are gonna cross it off at 80hz. it will dig deep naturally and just try to play freqs it doesnt need to play. 

high xmax is nice if you are gonna beat on em. 

high .qts will lend itself to an IB install and if you are gonna IB them in the door of car, it will make it easier than a low QTS driver that requires an enclosure. sure you can have a "too high" or "too low" of just about any spec.


----------



## Libertyguy20 (Jun 6, 2012)

apart from Fs specs which i understand, what is the range of an Xmas spec (from what to what) and where is it considered high or low per the industry...same for QTS....

i think that was your question james.


----------



## minbari (Mar 3, 2011)

xmax is just how far the cone will move in one direction and still stay in the magnetic gap. larger the xmax, the more sound it can produce. there are other considerations like non-linearity. LE changes. etc. the more the speaker is moving, in general, the more distortion will be heard.

I think most speakers have a QTS of 0.2-0.8 there are exceptions, of course.


----------



## jim walter (Apr 10, 2010)

Vas is relevant here; It relates to how much the volume of the door cavity will change your q. A very lightweight driver with a super soft suspension and a large cone area may have a low qts but a weak motor. Placed in a door, that q and resonance could creep up very quickly making it less than ideal even though it's free air TSP's looked good.


----------



## minbari (Mar 3, 2011)

yes, but low qts drivers generally dont work well in IB. that is a generalization, but true alot of the time. I am not saying VAS is irrelevent, but considering the volume of a door compared to the vas, it is not controlling factor.


----------



## Libertyguy20 (Jun 6, 2012)

found my speaker's stats...started a new thread.....i wonder if anyone on hear can answer what all the specs even mean


----------



## minbari (Mar 3, 2011)

good read

Thiele/Small - Wikipedia, the free encyclopedia


----------



## BuickGN (May 29, 2009)

Xmax and cone area are the ultimate determining factors for SPL in the lower frequencies regardless of everything else. Say from 63hz, most 6.5" are going to be able to hit their mechanical limits long before their thermal limits due to the huge excursion required at the lower frequencies. As you go up in frequency, say 100hz, mechanical excursion is no longer the limiting factor, power handling is since you won't hit the mechanical limits at the higher frequencies.

I'll take my current midbasses for example. Fs= 39hz, Qts .4 Xmax one way 4.5mm Xmech one way 10.5mm. They play low with ease unlike any other 6.5" I've heard. They don't sound like a small speaker trying to play low, they sound comfortable and relaxed...... up until they hit their 10.5mm mechanical limit. It doesn't seem to take much power at all to make them play down to 50hz. These things will play low right up to their mechanical limits relaxed and with ease.

My older midbasses which had a slightly higher Qts, Fs around 80hz had practically nothing under 80hz even with a lot of power. I could put a lot of power and eq on them to play lower but they just didn't sound good. 

I've run a lot of midbasses with Qts in the .5 and over range and Fs 70hz and higher and these Dyns are the first 6.5 I've run with a surprisingly low Fs, mid/low Qts and I absolutely love them especially when high passing at 70hz or under. 

I'm going to a 10" midbass right now with a .6 Qts but Fs is low at 40hz because I need more displacement but I'm not getting rid of the 6.5s just yet. From what I've read and heard it seems like low Fs, mid Qts and all of the displacement you can get would be ideal for the majority of setups out there. 

So there it is based off of my lack of experience. I like to cross the midbass at 63hz and if I could have any driver I wanted, it would be low Fs, .5-.6 Qts, and a ton of displacement. Some say for crossing them over higher, a higher Fs isn't a bad thing and high Qts can be good. I've never experienced that but I've read it several times.


----------



## Libertyguy20 (Jun 6, 2012)

very helpful....this is the type of feedback I've been interested in lately. if you would, please go to my recent post below and look at the stats and give me your initial opinion. Forget the brand if you will.

http://www.diymobileaudio.com/forum...-stats-your-opinion-thoughts.html#post1658930


----------



## james2266 (Sep 24, 2009)

BuickGN said:


> Xmax and cone area are the ultimate determining factors for SPL in the lower frequencies regardless of everything else. Say from 63hz, most 6.5" are going to be able to hit their mechanical limits long before their thermal limits due to the huge excursion required at the lower frequencies. As you go up in frequency, say 100hz, mechanical excursion is no longer the limiting factor, power handling is since you won't hit the mechanical limits at the higher frequencies.
> 
> I'll take my current midbasses for example. Fs= 39hz, Qts .4 Xmax one way 4.5mm Xmech one way 10.5mm. They play low with ease unlike any other 6.5" I've heard. They don't sound like a small speaker trying to play low, they sound comfortable and relaxed...... up until they hit their 10.5mm mechanical limit. It doesn't seem to take much power at all to make them play down to 50hz. These things will play low right up to their mechanical limits relaxed and with ease.
> 
> ...


Thanks once again. You have now been really helpful to me here and in a few PM. I think you owe me a PM too? We were going to go into a little more detail on a few midbasses? Oh well, I guess that can go for anyone with first hand experience with some of the better drivers out there. I really don't know what I want/need to do to get to the sound I crave. I think I keep getting closer to it with each tune lately. Adding in the Scanspeak 10f really was a big step in the right direction apparently. I was a little afraid this morning going to work as it sounded like I was getting some weird 'low static' or something coming from my right side pod. Don't know if it was midrange or tweeter but it was completely gone coming home so maybe it was something completely unrelated. I sure hope so as I don't want to have to replace either of those drivers. Those pod speakers and my sub are about the only components of my setup that I am 100% happy with. 

One more question for ya, what do you consider a ton of displacement when it comes to midbass? Is my current 6mm really solid or only average or even low? I am thinking it is upper good to solid but what do I know?:blush:


----------



## minbari (Mar 3, 2011)

6mm for a midbass is pretty good. My x65 have only 4.5mm and they whomp pretty good

Even if Buick doesn't like em 

Sent from my phone using digital farts


----------



## BuickGN (May 29, 2009)

james2266 said:


> Thanks once again. You have now been really helpful to me here and in a few PM. I think you owe me a PM too? We were going to go into a little more detail on a few midbasses? Oh well, I guess that can go for anyone with first hand experience with some of the better drivers out there. I really don't know what I want/need to do to get to the sound I crave. I think I keep getting closer to it with each tune lately. Adding in the Scanspeak 10f really was a big step in the right direction apparently. I was a little afraid this morning going to work as it sounded like I was getting some weird 'low static' or something coming from my right side pod. Don't know if it was midrange or tweeter but it was completely gone coming home so maybe it was something completely unrelated. I sure hope so as I don't want to have to replace either of those drivers. Those pod speakers and my sub are about the only components of my setup that I am 100% happy with.
> 
> One more question for ya, what do you consider a ton of displacement when it comes to midbass? Is my current 6mm really solid or only average or even low? I am thinking it is upper good to solid but what do I know?:blush:


I really depends on the high pass and the amount of power. My personal preference is lots of cone area and less excursion when possible. My current midbasses that are coming out of the car have 4.5mm linear, 10.5mm mechanical according to Dyn specs. At 70hz it's safe to say I'm at or past the 4.5mm most of the time. With the new setup I'll have 4.5mm more mechanical excursion and twice the cone area. I guess that's what I consider a ton of displacement lol. A 10" (more like a 9" in reality) highpassed no lower than 63hz is going to always be in it's linear range. Or a ton of displacement can be a 6.5" highpassed at 90hz where excursion is going to be low.

This is probably stepping into personal preference more than anything. I like to have excess cone area, little excursion, and a ton of power for those dynamic peaks. I want the option of crossing it at 50hz with plenty of output should I ever choose to and if I decide to stay in the 63-80hz range, excursion will be almost non existent. In a 3-way, I can't think of a reason not to go with the 10s. Some of this is my OCD, the 6.5" never bottomed at a 70hz highpass and always sounded great. I just wanted to add a little more headroom.


----------



## james2266 (Sep 24, 2009)

BuickGN said:


> I really depends on the high pass and the amount of power. My personal preference is lots of cone area and less excursion when possible. My current midbasses that are coming out of the car have 4.5mm linear, 10.5mm mechanical according to Dyn specs. At 70hz it's safe to say I'm at or past the 4.5mm most of the time. With the new setup I'll have 4.5mm more mechanical excursion and twice the cone area. I guess that's what I consider a ton of displacement lol. A 10" (more like a 9" in reality) highpassed no lower than 63hz is going to always be in it's linear range. Or a ton of displacement can be a 6.5" highpassed at 90hz where excursion is going to be low.
> 
> This is probably stepping into personal preference more than anything. I like to have excess cone area, little excursion, and a ton of power for those dynamic peaks. I want the option of crossing it at 50hz with plenty of output should I ever choose to and if I decide to stay in the 63-80hz range, excursion will be almost non existent. In a 3-way, I can't think of a reason not to go with the 10s. Some of this is my OCD, the 6.5" never bottomed at a 70hz highpass and always sounded great. I just wanted to add a little more headroom.


I would be very interested in hearing what the end product sounds like in comparison once you get those 182s in. I was strongly considering jumping to the MW172 a while back and may still at a later date. I would love those 182s too but no way they fit in my doors without serious modifications which I am unwilling to do right now. 

Well, I was out tuning earlier today for about the thousandth time and discovered something that is puzzling to me. The hole I have been getting at around 60 Hertz that I thought was a midbass problem appears to be a sub problem. I tried taking an rta reading of only the sub playing with it hi passed at 500 Hz in my Bit One. There was a pretty big dip from about 60 Hz to about 95 or so Hertz. The amp's crossover is on and I can't read what it is set at right now but I did have it set as high as it would go. Maybe it got moved the last time I was getting things moved around? I want to take a near field reading tomorrow of the sub and see if it is the sub/enclosure/amp causing this or if it is some weird vehicle thing. I really hope I don't have to yank the sub out to get to the amp settings as I will have to re silicon things then. Oh well, might be good to reset my gains for midrange/tweet anyways as I think gains are too high. Lower noise floor is always welcome. We'll see what tomorrow brings. Sounds like some fun day off projects.


----------



## minbari (Mar 3, 2011)

Depends on the enclosure. If it is a ported jobby, tuned really low, it will have a tendency to roll of sooner on the high end. Also if the sub had a high LE, it will roll off sooner.

Sent from my phone using digital farts


----------



## james2266 (Sep 24, 2009)

minbari said:


> Depends on the enclosure. If it is a ported jobby, tuned really low, it will have a tendency to roll of sooner on the high end. Also if the sub had a high LE, it will roll off sooner.
> 
> Sent from my phone using digital farts


It is a Morel Ultimo 12 in a sealed box roughly 1.4 ft3 in volume. Should be almost perfect. Box is not leaking that I can tell and has virtually no vibrations in any panels even with high volume.


----------



## Libertyguy20 (Jun 6, 2012)

Curious why you would be using your subs x/o if you have a bit 1 ?
My bit 10 is set for 25-70 [email protected] If its because the amp "/9 is undefeatable (like mine) there are ways around that


----------



## Ultimateherts (Nov 13, 2006)

It also depends on other factors like how well the door in dampened to even sealing the door. To me size matters as I prefer 8" mids to 6.5" some other members here will say otherwise. The real way to know is to try different drivers out. Specs can assist in your buying, but they are not the be all end all in how a speaker will perform. 

In short I look for low/small VAS and larger diameter...


----------



## james2266 (Sep 24, 2009)

Libertyguy20 said:


> Curious why you would be using your subs x/o if you have a bit 1 ?
> My bit 10 is set for 25-70 [email protected] If its because the amp "/9 is undefeatable (like mine) there are ways around that


No, nothing like that. My sub amp is the Audison LRx5.1k and I have read that the amp's sub crossover must be activated or the sub channel goes kind of crazy and sounds quite muddy. I also have the subsonic on if I remember too. I don't think that is really necessary now tho being this type of sub and in a sealed box.


----------



## jowens500 (Sep 5, 2008)

james2266 said:


> No, nothing like that. My sub amp is the Audison LRx5.1k and I have read that the amp's sub crossover must be activated or the sub channel goes kind of crazy and sounds quite muddy. I also have the subsonic on if I remember too. I don't think that is really necessary now tho being this type of sub and in a sealed box.


Another thing to note about the 5.1k sub section is, if you're not using the Audison VRC, you have to use the resister jumper that comes with the amp.


----------



## james2266 (Sep 24, 2009)

jowens500 said:


> Another thing to note about the 5.1k sub section is, if you're not using the Audison VRC, you have to use the resister jumper that comes with the amp.


Yes, I know that is installed on my amp. Thanks for the tip however.


----------



## Libertyguy20 (Jun 6, 2012)

That sucks that you "need" to use it or else...I would have to know...once you are all active...its tough to lose.

A great audio track I use for tuning the 60h range is u2's with or without you.

The 4 chords bass line at the beginning is 75h, 55h, 63h, 50h...give or take a few h +/-

I use that to see how well those ranges smoothly and loudly sound together...none of them should stand out over the other


----------



## james2266 (Sep 24, 2009)

Libertyguy20 said:


> That sucks that you "need" to use it or else...I would have to know...once you are all active...its tough to lose.
> 
> A great audio track I use for tuning the 60h range is u2's with or without you.
> 
> ...


Thanks for the song suggestion. I actually have that one in my itunes collection. I will have to use that one and try this out.


----------



## NoMids (Aug 22, 2009)

When comparing the HAT L8SE and the Morel MW9 the specs are similar at first glance, but there appear to be some big differences:

Fs: Morel MW9 = 38Hz / HAT L8SE = 41.5Hz

QTS: Morel MW9 = 0.59 / HAT L8SE = 0.627

Vas: Morel MW9 = 40L / HAT L8SE = 27.5L
With a Vas that's almost 30% less, is the L8SE better suited for door use?

The Xmax is a bit confusing: Morel MW9 = +/-4.75mm / HAT L8SE = 9.5mm (one way)
Does this mean that the HAT L8SE moves twice as much air as the Morel MW9?

Links if you want them:
Morel - http://www.morelhifi.com/wp-content/uploads/2011/10/ELATE.pdf
HAT (page 39) - http://hybrid-audio.com/downloads/specification-libraries-and-reference-guides/LegatiaSE_Manual.pdf


----------



## james2266 (Sep 24, 2009)

NoMids said:


> When comparing the HAT L8SE and the Morel MW9 the specs are similar at first glance, but there appear to be some big differences:
> 
> Fs: Morel MW9 = 38Hz / HAT L8SE = 41.5Hz Morel should play lower frequencies slightly better here with the lower fs.
> 
> ...


These are the exact kinds of questions I have been looking for definitive answers on. I have highlighted my take on each speaker parameter above as I know it right now. I also give my opinion on which would perform better on each parameter and why I think this is. I hope that some guys that know more than I will correct me if I have any of this wrong here.


----------



## NoMids (Aug 22, 2009)

Thanks, James. I really hope that someone can expand on the meaning of the difference in Vas numbers and how these numbers are relevant to a typical door enclosure.


----------



## james2266 (Sep 24, 2009)

NoMids said:


> Thanks, James. I really hope that someone can expand on the meaning of the difference in Vas numbers and how these numbers are relevant to a typical door enclosure.



So do I as I think alot of guys have the same questions and when you are talking the costs of some of the drivers I am looking at, you kinda want to grab the right driver for what your intending on using it for. I must say that HAT L8SE seems pretty impressive on paper however. It is a shame it is so deep tho and about 25 mm too wide for my application.

I have actually been strongly looking at the Scanspeak midbasses after my good impressions I am having with my 10f midrange. I would love anyones opinions on the Discovery line 6 inch midbass model number # 18W/4434G00. I have also been wondering if I should save my pennies and get the Revalator model # 18W/4531G01 or 18W/4531G00.I am a little concerned by the paper cones on the revalator due to me putting it in my doors. We do get alot of crazy weather up here. The first Rev. number is a wood fiber cone tho so would that be better with possible accidental water? There is also the fact that the Revs are more than 3 times the costs of the Discovery! Are they really 3 times the driver?


----------

