Midbass Diameter - How to Decide?

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I believe the Peerless 830883 to be a good choice. It´s a 6.5 " driver. I´m going to design a 2-way system for a friend with it, intended to be used with a sub (driver is an Aurasound NS 10-797-4A). The Peerless driver will be used together with an Eton ER4 AMT (air motion transformer).

While the Peerless driver shows a resonance at about 4.5 kHz this isn´t much of an issue and can be tamed by a notch filter, the trickiest part for me is that the Eton AMT is a very "fast" tweeter. I use it myself with Accuton C79 drivers and they integrate quite good.

Peerless (Tymphany) You find it by choosing Peerless-Mid woofer-61/2-8 ohms or possibly by following this link.

http://www.tymphany.com/datasheet/printview.php?id=3

BTW I prefer to start by building just one speaker. If the result is not to my liking I can change direction. The Peerless driver isn´t expensive though.
 
Originally posted by BlueWizard
I would take the opposite approach to what Myhrrhleine said, though the difference in our approaches is more philosophical than literal.

I would go for the largest speaker I could find that would still give me the high range I needed. Of course, this assume that it would also cover the bass range as well.




why?
given otherwise identical performance, why largest?


I live by the philosophy that to get Big Sound, you have to move Big Air, and to move Big Air, you need Big Speakers.

From my perspective, with a few exceptions, an 8" speaker is the smallest I would go, and more than likely, I would use at least two of them. But I am also not likely to use a Sub, so my speaker (hypothetically) would have to deliver decent bass on their own.

I mean, I think Tang Band and HiVi make 1", 2", and 3" full range speakers (more or less), but can they move enough air so I can hear the bass?

So, from the perspective of solid uncolored uncompromising bass, I would go for the largest possible speaker that would fit the design requirements. And logically, the design requirements would include decent midrange response.

Now I readily admit that, in general, the larger the speaker, the less likely you are to get the midrange you need, but, conversely, the smaller the speaker, the less likely you are to get the bass you need. Somewhere in all our searching, we hope to find a speaker that reaches a compromise between the two.

5", 5.25", 6", 6.5", and in some cases 7" speakers have fair bass and fair midrange, though logically, they might require some tweaks.

An 8" speaker that can truly and functionally run up in the 2khz to 3khz range is a rarity, and in speakers that I can afford, an extreme rarity.


So, even with all their complexities, I tend to favor big bass big box 3-way designs. But even then, it is difficult to find three speakers that can smoothly mate together.

Steve/bluewizard
 
J.R.Freeman said:
what I mean is a small woofer (or big midrange!) which would make for a nice 2 way, reaching down to 50 Hz or so, and being able to cross-over at 2 KHz or more.

Going by the above statement, if this is really what you think you'd like to do, go for a 3-way with a 6.5" midrange. Personally, I'd shoot for a bit higher sensitivity than your usual inefficient hi-fi distortion generators tho, but that'd most likely put you in the territory of ribbons or compression drivers (not really a bad thing!). For crossing at 2 KHz, 6.5" is actually getting close to the limit. With an 8", usually about 1.5 KHz or so (although, like I said earlier, I just spent $200 on some 12" pro woofers that I'm planning to cross somewhere around that same freq.. it's far from optimal tho!) Anyway, yeah.. if it were me, and I was going that route.. I'd be looking at things like the PHL 1120, Audax PR170M0 (if you can still get them?).. stuff like that. After that, find a nice ribbon to go with it. You could even grab a pair of ESS AMT-1 Heil dipoles from eBay (they sound really nice, I still love them!). Under all of that, find a 12" woofer (15" would be easier tho!) that'll end up with a -3dB point at your desired crossover frequency (50 Hz you said?) to the subwoofer(s). Then, use the 2nd order highpass in most receivers/preamps/processors and set it to that same frequency. You'll end up with a 4th order highpass to match with your sub(s). If you spend enough time with it, you'll end up somewhere between 90 and 95 dB/watt from 50 Hz to 20 KHz+ after everything is said and done, even with a power sucking passive xover. Of course, it all just depends on what you end up getting and how you go about doing it. Anyway, if this is really what you want, that's what I'd recommend.. a 3-way with a nice 6.5" midrange that's fairly efficient.

edit:
I think I was typing while BlueWizard posted. I think he and I are on the same page. :)
 
I believe the core of loudspeaker design is in the fact that you can´t have it all and your priorities has to be modified and adapted to reality or to put it in another way; the laws of physics.

We have a different situation if we want to integrate two "midbass" drivers into the equation compared to one per speaker. We need to think of the integration to the tweeter as well as a sub in both cases. We may find a "midbass" driver with the "right" sensitivity but it may not be possible to find a tweeter to match it it to.

Thus; design is a complex activity which includes math, simulation, trial and error, measurements and it is impossible to disregard experience or "intuition" although you can gain insight from other people, just like here. (You might as well be confused by our disparate suggestions)

It´s a challenge to make your own design instead of going for a more predictable kit that may be auditioned as a finished pair of speakers.

In your situation I think "learning by doing" is the right description of the activity and I can possibly suggest some combinations of drivers that will meet your needs. But then we are more up to a "kit approach" and this wasn´t your intention I believe?
 
The golden mean said:
Sorry,
Focal don´t sell drivers to the public except for car audio. Of course some drivers for this destination can be used at home.

Audax, they have been into problems and possibly manufacturing of some drivers are kept running by some employees.
---------------------------------
Audax
Hello Golden Mean.
This is not true in my country, it is not.
So do not make me appear as telling lies. Please!
It does not suit you ;)
How much sorry you are, I do not know.
But my guess based on observation of people,
is that you are not very sorry at all :D :D


I can get Focal drivers and Audax excellent midrange drivers.
Which I have ;)
Is also the possibility to contact Focal/Audax
for anyone with no supplier in country. And see what they say.
if they really want diy peolle to use there stuff, or not :D

Audax is a very good alternative for DIY speaker builders.
If we really want the best quality we can get. (Otherwise there are plenty of budget options ....)

For example,
I can mention that one of the world's leading hi-fi speakers maker
vonSchweikert.com has used mostly Audax high SPL kevlars for his midrange drivers.

Otherwise, I notice with pleasure but no big surprise,
there is not much opposition here to my statement of the Focal Audax high quality regarding good audio.
Lineup Speaker Lab
 
lineup said:

Hello Golden Mean.
This is not true in my country, it is not.
So do not make me appear as telling lies. Please!
It does not suit you ;)
How much sorry you are, I do not know.
But my guess based on observation of people,
is that you are not very sorry at all :D :D


I can get Focal drivers and Audax excellent midrange drivers.
Which I have ;)
Is also the possibility to contact Focal/Audax
for anyone with no supplier in country. And see what they say.
if they really want diy peolle to use there stuff, or not :D

Audax is a very good alternative for DIY speaker builders.
If we really want the best quality we can get. (Otherwise there are plenty of budget options ....)

For example,
I can mention that one of the world's leading hi-fi speakers maker
vonSchweikert.com has used mostly Audax high SPL kevlars for his midrange drivers.

Otherwise, I notice with pleasure but no big surprise,
there is not much opposition here to my statement of the Focal Audax high quality regarding good audio.
Lineup Speaker Lab

So, please tell us were to buy these! Of course things can have changed and if so we have more to choose from and I´m only happy.
I´m talking about production and not some old inventory. Audax have had problems but I wrote that they might still run some production. Your remark about "no opposition" seems a bit strange to me. ;)
 
Here are just a few random thoughts.

Today, the speaker building game has completely changed than it was back in the day.

Back in the day, the logical Bass-to-Mid crossover range was roughly 500hz to 1000hz, with Mid-to-High crossovers in the 3khz to 6khz range.

The low-to-mid was carefully chosen to be 500hz or above because the peak musical power is in the 250hz to 500hz range (per Badmaieff/Davis; full orchestral music). Consequently, 500hz or above seemed the perfect place to crossover in a 2-way or 3-way system.

Today, with the influence of Subwoofers, that has changed. I have a pair of JBL towers that cross two 8" woofers at 300hz, leaving a single lonely 4" cone midrange to handle 300hz to 4,000hz. And this is very common, seeing single cabinet speaker 3-way crossovers in the 100hz to 500hz range. To me, though more so in concept than reality, these designs are more a 2-way speaker with a built-in subwoofer, rather than a standard 3-way system (again, in concept, not reality).

Because of this tendency to crossover so low, a real need for MidBass speakers arose. This includes front speakers that are intended to be used with Subs. You can compromise a bit on the low bass in the Fronts, if the Sub is going to be handling that range.

In this case, fronts/subs, your MidBass doesn't really need to go much lower than 100hz; 80hz is fine, 60hz is a luxury.

As an offshoot of the availability of MidBass speakers, the concept of small 2-way speakers that can do a fair job of standing alone, and do an excellent job of acting a Surround System Fronts, arose. Now the market is flooded with them, and in some sense, is the preferred speaker for young people.

In away, woofers are like cars. Back in the day, we wouldn't consider anything less than a V8 engine. Today, V8's aren't even on the radar screens of kids. They want small high-reving 4 cylinders.

Shifting the analogy to speakers, back in the day, we wouldn't consider anything less than a 10" woofer, with 12" being the standard, and 15" being a nice luxury. In a discussion in another audio group, someone was agonizing over whether to buy a tower with a 6.5" woofer, or go for one with a 10" woofer. This person was literally afraid that the 10" would be too big for the room. Conversely, they were worried that the 6.5" would be too small and they would be upgrading in the near future (these were PMC transmission line towers; very expensive). I tried to impress on them, that a 10" speaker was a small speaker, and as I've said, back in the day, we wouldn't have considered anything less than a 12" speaker, regardless of the size of the room.

How is all this relevant to the current discussion? Well, as people try to convince the original poster to go to a 3-way design, I can't help wondering exactly what they consider a 3-way design to be? To me it is a combination of speakers crossing over at 800hz and something in the 4khz to 6khz range. In this case, a bass is a bass, and a midrange is a midrange. But I'm suspecting that this is not the vision of others, and that new vision completely changes the nature of the speakers needed.

In summary, a LowBass/MidBass/High is a completely different speaker than the good old Bass/Mid/High speaker.

Rambling again...sorry.


Next, is the one critical issue of cost. I'm in the bargain basement of speaker building. The thought of spending $50 on a woofer practically puts me into a faint. The thought of spending $200 to $300 on a woofer would probably put me into a coma.

And this is relevant because it affects the speakers we are going to suggest to the original poster (J.R.Freeman). If his budget is in the $0 to $50 per woofer range, that is one thing, $50 to $100 range is a whole new ballgame, and above $100 per speaker puts him in a whole new league of speakers with a whole new range of possibilities.

I think, if only in concept, if J.R. Freeman set a dollar amount to his hypothetical speaker, we could do a better job of narrowing it down both literally and conceptually.

For what it's worth.

Steve/bluewizard
 
BlueWizard said:
Next, is the one critical issue of cost. I'm in the bargain basement of speaker building. The thought of spending $50 on a woofer practically puts me into a faint. The thought of spending $200 to $300 on a woofer would probably put me into a coma.
You would need to be a cat to listen to mine then. And you'd be on about you 7th life.

I agree with the rest of your post.
 
Ex-Moderator R.I.P.
Joined 2005
A midbass hifi driver is different from a PRO midbass, simple as that
A hifi midbass is 5-6", and an 8" is considered a woofer
In the PRO world almost anything less than 15" with few exceptions is considered a midbass and even a 12" can be a pure midrange
In hifi world the midbass will handle both bass and mids
A PRO midbass will handle only...midbass
No point in complicating things

I asked Jim about his subs, and still waiting fore the answer which could be helpfull in choosing the right design in terms of SPL and so forth...?
 
tinitus said:
A midbass hifi driver is different from a PRO midbass, simple as that
A hifi midbass is 5-6", and an 8" is considered a woofer
In the PRO world anything less than 15" is a midbass and even a 12" can be a pure midrange
No point in complicating things
How have I complicated things? I use 15's as midbasses NOW. Because 6.5" is "considered" a hifi midbass by you does not mean it's better or more appropriate because of conventionality.
 
Brett:

As no one has bothered to define what we are actually discussing, I'll give my opinion. Midbass to me is say 60-250Hz or so. I can cover that with a 12 or better yet a 15 with high efficiency/sensitivity, a sealed enclosure and no breakup nastiness.


Herein lies the heart of the problem.

How is 60-250hz mid-bass, I see the bass, but not the mid. Unless of course, rather than bass AND mid, you mean the middle of the bass range.

But how is that even the middle of the bass range. It seem more like just plain bass to me.

Again, I sense the influence of Subwoofers and theater surround systems. To some people, heavily influenced by Subs, Bass means 10hz to 100hz. But that is extremely low bass by any standard.

I can't hear anything below 30hz, and at sane volume levels, I can't hear or feel anything below 30hz. Though I admit, few of us listen to movies on theater systems at sane levels. We don't just want to hear the sound; we want to experience it, and I can understand that.

So, again, how is 60hz to 250hz MidBass? How is it not just plain Bass?

I'm not contradicting you or implying that you are wrong. I'm just pointing out how loosely this term 'MidBass' gets thrown around.

Interesting discussion.

Steve/bluewizard
 
Ex-Moderator R.I.P.
Joined 2005
Seems like a battle on words

Its like I said

HIFI midbass is 5-6" and able to play BOTH mids and bass, except the lowest bass, 50-3khz...hence the term midbass...mids(and)bass

a PRO midbass plays midbass, 60-1khz

Its not that complicated...the real joker is the tweeter

But ofcourse we all know there are exception, and ways to stretch the bandwidth

Still wondering what Jim wants...a discussion or suggestions
 
Hi J.R. ,

as we can see, there are many answers ranging from
"smallest" to "largest".

My answer would be "smallest possible for reaching the
needed displacement volume".

In the 2-ways i had designed and built i mostly chose to
use 2 smaller drivers instead of 1 larger single driver.

This approach reduces problems and i would still prefer it
compared to a conventional 3-Way in most cases.

One should reduce the needed displacement volume as
far as possible either by a proper BR alignment or by using
a subwoofer.

Both approaches reduce problems further.

One problem which is present in almost every 2-Way is the
change in angular dispersion at XO.

When using usual dome or ribbon tweeters, it is difficult
to match them with larger drivers, if we choose a XO of
2,1 to 2,3 Khz, which to me is a good XO frequency for
our hearing system.

When choosing HF Systems with larger area like
esl panels or waveguide systems, you can choose lower
XO and larger midbass drivers. Matching the dispersion then
depends highly on the HF System used.

It is all about compromise and listening habits ...


Cheers
 
Greets!

FWIW:

From "Complete Guide to High End Audio":

20-40 Hz: deep bass
40-80 Hz: mid-bass
80-160Hz: upper bass
160-320Hz: lower mid-range
320-640Hz: (middle) mid-range
640-1280Hz: upper mid-range
1280-2560Hz: lower treble
2560-5120Hz: middle treble
5120-10240Hz: upper treble
10240-20480Hz: top octave

This is from "How to Read The Absolute Sound" reprinted in Guide to HighEnd Audio Components 1992/1993 (it has been printed infrequently over the years):

below 32 Hz: Extreme bottom
20-40 Hz: low bass; bottom octave
40-80 Hz: mid bass
80-160Hz: upper bass
160-320Hz: lower mid-range
320-2560Hz: mid-range
2560-5120Hz: upper mid-range
5120-10240Hz: highs; lower highs
10240-20000Hz: extreme highs; top octave

Until these were sent to me ~ten years ago, I used an ancient Bell Labs one that makes more sense to me and was still in common use as late as the mid '60s when I originally quit 'bench racing' audio:

infrasonic: <20Hz
bass: 20-128Hz
midbass (tenor or alto): ~128-896Hz
mids (soprano): ~896-5,000Hz
treble (overtones): ~5,000-10,000Hz
super treble: 10-20kHz
ultrasonic: >20kHz

GM
 
TBH, I don't think an abstract definition will help, one needs to look at actual drivers to find which combine both the high freq characteristics AND bass characterisics desired.....usually it's a matter of compromise to get both, or an impetus to develop more complex systems....
 
Hi G.M. ,

thank you for clarification.

As i understood J.R. Freeman he is looking for a driver
covering the range from "deep-bass" to "lower treble".

For this is an extremely wide range to be covered by a
single driver (about 6 Octaves when we are statisfied
with lower cutoff at 30 ..40 Hz and using a usual tweeter)
one can imagine that the "bigger is better" approach does not
lead very far.

In a usual 2-way the tweeter has to cover only 3 octaves.

When compromising the design due to budged available,
such a system will suffer much more from choosing a poor
LF driver, than from compromising the tweeter - there are lots of
low cost tweeters available, which perform well.

To me choosing the Diameter of the LF driver is very much
dependent from choosing the cone material.

When choosing a larger driver you cannot avoid using it in
the range of modal vibration. Which in turn suggests choosing
a cone material with high damping like e.g. polypropylene or
compound materials like coated paper.

When attempting pistonic motion from lower midrange to lower
treble there may be some small drivers with metal cones to
come close.

This one is a fairly good example i used it once in a two way
up to 1Khz

http://www.visaton.com/de/high_end/tiefmittelton/al130_8.html

This one may be interesting for higher XO, but will compromise
the deep-bass to mid-bass range even more.

http://www.visaton.com/de/high_end/tiefmittelton/ti100_8.html

There may be some fullrange and widerange drivers
too, which are suitable for 2-way.

Concerning larger drivers, the LF driver used in the
Tannoy 800 Monitors i heard recently, seems to work
fairly well in midrange and lower treble ... unfortunately it
is a coax and the tweeter in there sounds evil to me.

http://www.tannoy-speakers.com/s.php?product=160

But maybe there are LF drivers with comparable performance
from midrange to lower treble.

Cheers
 
Brett said:
As no one has bothered to define what we are actually discussing, I'll give my opinion. Midbass to me is say 60-250Hz or so. I can cover that with a 12 or better yet a 15 with high efficiency/sensitivity, a sealed enclosure and no breakup nastiness.

..Agreed 100%. This is also how I've always used the term "midbass". :)

Also, if it's a heavier 15 or 18 that works best in a vented enclosure down to 40-50 Hz or so, I just call it a woofer.
 
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