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JonJT
12-30-2006, 12:32 AM
Out of sheer boredom, I decided to lurk these forums in search of answers to an old question. Some time ago I researched the possibility of putting horns in my car and dug up a load of information, as well as one burning problem:

High sensitivity midbass drivers

I have a pair of Koda 8's I bought on impulse which would have worked well with a normal unloaded front stage, but I feel they lack the sensitivity to really keep up with the dynamics of the horns and the highly sensitive midrange I plan on using. When I dropped the project, I left without finding a midbass driver that had both the displacement to match a heavy subbass stage and the sensitivity to keep up with the rest of the front stage. After lurking a little, I see this problem still exists.

The B&C 8NDL51 is the best thing Ive seen so far, but I fear it lacks the displacement capabilities to reach down to my desired X-over point. I haven't done too much searching for high sensitivity woofers that would work, but I did come across a nice 10 inch woofer made by the same company. The B&C 10NW64.

This woofer trumps the Koda 8's I have in displacement and is much more sensitive at 96db. My only real worry is the woofers behavior in an IB environment. My knowledge of first order setups is quite rusty, as I've been cramming engineering principals into my brain for the last 4 months. So, the purpose of this post is to get your input as far as this woofers pracitcality in an IB alignment as well as the feasibility of making such an alignment within the average car door.

In the mean time, I'm going to go brush up on speaker design theory so I can make some decisions myself.

Good to be back.

helotaxi
12-30-2006, 11:40 AM
I'm thinking that the average car door isn't going to have the air volume required to get true IB performance out of those drivers. An install behind a heavily modded kickpanel that used either the fender or the great outdoors to get an IB setup would be the option there. If you wanted a more controlled environment, sealing the fender and filling it with expanding foam and then carving out the volume desired would probably be the way to go.

Couple of questions, why a 3-way front stage with horns? Most every car horn I've seen was capable of playing low enough to couple nicely with just a midbass. Second, why not just find a good midbass and power the crap out of it rather than trying to find one that is really sensitive? The combination of sensitivity and low extension needed to get it to blend nicely with a powerful substage are going to dictate an enclosure that will mke it pretty much impossible to practically integrate into a car without serious creativity and modification. Forgo sensitivity to get a small enclosure requirement and take advantage of the readily available cheap amplification out there.

Just my thoughts...

JonJT
12-30-2006, 12:53 PM
I'm thinking that the average car door isn't going to have the air volume required to get true IB performance out of those drivers. An install behind a heavily modded kickpanel that used either the fender or the great outdoors to get an IB setup would be the option there. If you wanted a more controlled environment, sealing the fender and filling it with expanding foam and then carving out the volume desired would probably be the way to go.

Couple of questions, why a 3-way front stage with horns? Most every car horn I've seen was capable of playing low enough to couple nicely with just a midbass. Second, why not just find a good midbass and power the crap out of it rather than trying to find one that is really sensitive? The combination of sensitivity and low extension needed to get it to blend nicely with a powerful substage are going to dictate an enclosure that will mke it pretty much impossible to practically integrate into a car without serious creativity and modification. Forgo sensitivity to get a small enclosure requirement and take advantage of the readily available cheap amplification out there.

Just my thoughts...

I'm going 3 way front stage because its even harder to find a woofer that can cover the midrange and the midbass while blending property with the horns I want to use. I am looking at the CDes for a number of reasons. Price, and size are the foremost important. They don't extend that far and for aformentioned reasons, it would be much easier to find the right combination of woofers to make a 3 way front stage than a two way.

Now, over powering an inefficient, low sensativity woofer is an option, but it still won't produce the dynamics and play with the same "ease" as an efficient, sensitive woofer would. Its been done before and I've been warned with much vigor by more experienced horn owners not to mix and match a midbass with, for examble, 88db 1W/1M sensitivity with a horn at 97db 1W/1M or greater.

JonJT
12-30-2006, 01:43 PM
I ran the woofer through WinISD quickly and responce down to about 80hz was pretty good in a 6 liter sealed enclosure. With some work and some Eqing, I bet they would do pretty well mounted in door.

mhmmmmmmm

req
12-30-2006, 01:46 PM
hows about this?

http://www.criticalmassaudio.com/catalog/index.php?act=viewProd&productId=5

http://www.criticalmassaudio.com/catalog/images/uploads/MB82_1-(1).jpg

JonJT
12-30-2006, 02:31 PM
hows about this?

http://www.criticalmassaudio.com/catalog/index.php?act=viewProd&productId=5

http://www.criticalmassaudio.com/catalog/images/uploads/MB82_1-(1).jpg

That woofer is actually very insensitive. Its rated at 2.83 volts into 2 ohms, which works out to 4 watts. You have to subtract 6 db from the sensitivity rating to compair it properly to the B&C woofer I mentioned. Its actual sensitivity is then 87db 1W/1M. I think my Koda 8s are more sensitive and probably displace more as well. Although, I will never actually know about the displacement unless that company releases some more detailed T/S and electro-mechanical data.

req
12-30-2006, 02:55 PM
well dont forget.

these are 2ohms. so in my opinion - that makes up for a lower sensitivity does it not?

and as far as kodas are concerned. they are nigh on 5" deep. not like you can install those in a car door without a lot of modification. they also have a very low bandwidth, more suitable as a subwoofer than as a dedicated midbass. IIRC, they don't go above 800hz without severe breakup. these suckers can play up to 1khz easy to mate with horns, they have a good amount of cone area and significant displacement over a 6.5. and these are 2ohm which imo - is an awesome benefit for a midbass speaker.

:naughty:

JonJT
12-30-2006, 03:15 PM
well dont forget.

these are 2ohms. so in my opinion - that makes up for a lower sensitivity does it not?

and as far as kodas are concerned. they are nigh on 5" deep. not like you can install those in a car door without a lot of modification. they also have a very low bandwidth, more suitable as a subwoofer than as a dedicated midbass. IIRC, they don't go above 800hz without severe breakup. these suckers can play up to 1khz easy to mate with horns, they have a good amount of cone area and significant displacement over a 6.5. and these are 2ohm which imo - is an awesome benefit for a midbass speaker.

:naughty:

The fact that isn't 2 ohmns doesn't actually make up for the lack of sensitivity. The 2 ohmn rating only means that you will be able to push more current through the voice coils for a givin voltage. If you look at the B&C woofer I cited, you will see that though it is an 8 ohmn transducer. It also has a much high sensitivity rating. Since it is 8 ohmns and the critical mass audio woofer is 2, you will be able to push about 3 times teh wattage through the critical mass audio woofer, but the B&C has the ability to play louder at maximum because it is over 3 times more sensitive.

This higher sensitivity also means the woofer will respond to changes in input power faster and have better dynamics.

All this means higher volumes, better transient responce and cooler amps.

JonJT
12-30-2006, 03:24 PM
Also, the Critical mass audio woofers are rated to play up to 1khz, but I was wondering what placing the motor right int he middle of the cone does for breakup of high frequencies. It can't be good. I'd love to see concrete testing of that woofer at 800+hz. In anycase, its not the best woofer for use with horns anyway you look at it. It would deffineatly be the weak link in a 2 way system with nice horns and a large, powerful sub stage. Ideally, I'd need more displacement (only guessing here, but the surround doesn't look like it could take any more than 7mm +/- of cone movement) and more sensitivity.

And yes the Kodas are big Mofos but I'm prepaired to modify my doors when the time comes. I never intended to try to stick the midbasses in the stock location without any door modification.

req
12-30-2006, 03:25 PM
that is true :)

but i seriously dont have anywhere near 150w@8ohm to give this sucker to keep up with my CD2 HLCD's and pair of IDQ15's.

and on top of that, are they suitible for infinite baffle? i see they want .5 cubes for an enclosure and thats way more than im even willing to give any midbass. im not modifying my doors or building fiberglass pods. i did that in my saturn with great results - but im not willing to hack up my next car that im paying 15k on if you get my drift.

i want an IB speaker that will play from 50hz to 1.2khz.

i dont deny that that transducer would be optimal, but i am wary about the 8ohm voicecoils...

JonJT
12-30-2006, 03:40 PM
that is true :)

but i seriously dont have anywhere near 150w@8ohm to give this sucker to keep up with my CD2 HLCD's and pair of IDQ15's.

and on top of that, are they suitible for infinite baffle? i see they want .5 cubes for an enclosure and thats way more than im even willing to give any midbass. im not modifying my doors or building fiberglass pods. i did that in my saturn with great results - but im not willing to hack up my next car that im paying 15k on if you get my drift.

i want an IB speaker that will play from 50hz to 1.2khz.

i dont deny that that transducer would be optimal, but i am wary about the 8ohm voicecoils...

Well to each there own. For me, power is cheep. Its not TOO hard to find a 2 channel amp tht can push 150+ watts into 8 ohmns, you will just have to pay big bucks for it.
As an aside, B&C does mention that other impedances are avaliable for this woofer, but you need to ask for them. I donno what a 4 ohmn version would do for the other T/S parameters, but it couldn't be very different.

And I am willing to hack up my doors or try something different with an IB venting to the outside. Or maybe even an aperiodic. As I glance over the specs of this woofer again, it looks even more sutiable for a 2 way system with horns cause it looks to have the extension to match a pair of minihorns AND has the displacement I need down low. If I could find some way to IB/aperiodic this sucker either in doors or in pods I bet it woudl rock!

Thnking
12-30-2006, 03:42 PM
I doubt you're going to find high sensitivity mid-bass driver, as sensitivity is increasing bass output decreases.

The damping of the woofer (system, once it's installed in a box) describes the transient response, the sensitivity describes the amplitude.

Really what you're looking for is a linear(for transient response), higher displacement(for an IB application), higher power handling (to minimize EQ'ing) mid-bass.

JonJT
12-30-2006, 03:52 PM
I doubt you're going to find high sensitivity mid-bass driver, as sensitivity is increasing bass output decreases.

The damping of the woofer (system, once it's installed in a box) describes the transient response, the sensitivity describes the amplitude.

Really what you're looking for is a linear(for transient response), higher displacement(for an IB application), higher power handling (to minimize EQ'ing) mid-bass.

The QTC your saying? I wish that critical mass audio woofer had published T/S data.

Another question. If qtc alone describes trancient responce, then why are some of the older guys saying that one should only use high sensitivity woofers with horns? I was warned severly against using typical woofers with even a mini horn.

T3mpest
12-30-2006, 07:53 PM
I'm also working on a similar install to yours and have had similar issues. The B&C's seemed like the a good choice to me. Other good midbasses for horns are hard to find. Here's a couple ones though. One driver that might be a decent choice, again it's discontinued is the peerless xls. It's 90db effecient, which isn't terrible, but is a good sized 8 and handles alot of power. I think it might have the dynamics needed for a horn system. What midrange are you planning on using, audax?

IDQ 8
JL IB8
JBL2 118

Audax and PHL both have high sensativity midbass, I've been told PHL mids are REALLY nice, by quite a few sources. Not sure how they'd work in a car environment though, it'd take some work, that's for sure.

Thnking
12-30-2006, 09:04 PM
The QTC your saying? I wish that critical mass audio woofer had published T/S data.

Another question. If qtc alone describes trancient responce, then why are some of the older guys saying that one should only use high sensitivity woofers with horns? I was warned severly against using typical woofers with even a mini horn.
Yes, primarily QTC is the controller of the transient. The actual transient is a function of the acoustical model of the speaker as current/voltage is applied to the voice coil over a period of time. Sensitivity is more or less efficiency (amplitude in the output function). But sensitivity can be an indicator of damping. Unfortunately, increases in damping decreases bass output. So a highly sensitive speaker will generally have low amplitude bass output.

People will tell you to match sensitivity because of the large difference between a horn and standard woofer...over 10db in some cases. What a horn does is takes a transducer and helps to match air loaded impedance. So it increases efficiency. It also reduces distortion due to lower power needed to meet the same DB level, and lower air impedance distortion.

IMO, it's better to have a linear woofer, which can handle a lot of power to match the output of the horn, than to have a highly efficient woofer and EQ the low end sometimes 6-10db.

req
12-30-2006, 09:41 PM
yeaaa. um.

my CD2's are 109db 1w\1m .... thats like. 20db :crap:

lawl.

djdilliodon
12-30-2006, 10:39 PM
If CDT works something out and makes the 06+ a reality you can get solid results from a power range of 75-150xrms at 4ohm in a well deadened door IB. I have a pair myself and these things can extend super low and play to 1khz very cleanly. I have them off 150x2rms but with gains set very low matched to a pair of CDT es-02 2" midranges (also not out yet) with 75x2rms all run active with the 06+ at 40-1khz and the 02's from 1khz up. The 06+ has 15mm of xmax and has all the output i can ever imagine any 6.5" can have and how low they can play in even the bass freq is just amazing. You would never think they are 6.5's. CDT should release these after ces but since these drivers are built by hand and believe me they are top notch quality they are just working on how they can make them affordable. Knowing cdt they will work out something and when these are first released they will have a special on them but eventually will go up.

T3mpest
12-30-2006, 10:46 PM
If CDT works something out and makes the 06+ a reality you can get solid results from a power range of 75-150xrms at 4ohm in a well deadened door IB. I have a pair myself and these things can extend super low and play to 1khz very cleanly. I have them off 150x2rms but with gains set very low matched to a pair of CDT es-02 2" midranges (also not out yet) with 75x2rms all run active with the 06+ at 40-1khz and the 02's from 1khz up. The 06+ has 15mm of xmax and has all the output i can ever imagine any 6.5" can have and how low they can play in even the bass freq is just amazing. You would never think they are 6.5's. CDT should release these after ces but since these drivers are built by hand and believe me they are top notch quality they are just working on how they can make them affordable. Knowing cdt they will work out something and when these are first released they will have a special on them but eventually will go up.
15mm 1 way or 2?!?!

req
12-30-2006, 10:50 PM
thats def a wrong figure.

its eaither 15mm 2 way or not right at all. theres no way an 8" will be doing 30mm of movement and keep up the transient response for midbass action...

i just cant see it.

any pics of these cdt hand built thingies?

JonJT
12-30-2006, 11:05 PM
I'm also working on a similar install to yours and have had similar issues. The B&C's seemed like the a good choice to me. Other good midbasses for horns are hard to find. Here's a couple ones though. One driver that might be a decent choice, again it's discontinued is the peerless xls. It's 90db effecient, which isn't terrible, but is a good sized 8 and handles alot of power. I think it might have the dynamics needed for a horn system. What midrange are you planning on using, audax?

IDQ 8
JL IB8
JBL2 118

Audax and PHL both have high sensativity midbass, I've been told PHL mids are REALLY nice, by quite a few sources. Not sure how they'd work in a car environment though, it'd take some work, that's for sure.

The Xls crossed my mind but as you said its discontinued so I'm taking themoff thei list
I'll look at those other woofers as well.

And yes, I will be using the Audax

JonJT
12-30-2006, 11:09 PM
Yes, primarily QTC is the controller of the transient. The actual transient is a function of the acoustical model of the speaker as current/voltage is applied to the voice coil over a period of time. Sensitivity is more or less efficiency (amplitude in the output function). But sensitivity can be an indicator of damping. Unfortunately, increases in damping decreases bass output. So a highly sensitive speaker will generally have low amplitude bass output.

People will tell you to match sensitivity because of the large difference between a horn and standard woofer...over 10db in some cases. What a horn does is takes a transducer and helps to match air loaded impedance. So it increases efficiency. It also reduces distortion due to lower power needed to meet the same DB level, and lower air impedance distortion.

IMO, it's better to have a linear woofer, which can handle a lot of power to match the output of the horn, than to have a highly efficient woofer and EQ the low end sometimes 6-10db.

Even if a highly efficient woofer has a large cone and great pistonic movement, it still not be that great at reproducing low frequencies?

JonJT
12-30-2006, 11:10 PM
yeaaa. um.

my CD2's are 109db 1w\1m .... thats like. 20db :crap:

lawl.

dam, that *****....................

T3mpest
12-30-2006, 11:10 PM
The Xls crossed my mind but as you said its discontinued so I'm taking themoff thei list
I'll look at those other woofers as well.

And yes, I will be using the Audax
Figured, I'm trying to get some phl 2520's for my midranges 8 inches of midrange, hells yeah! Kicks are going to be half my floor, the other half being some IDQ 8's......hahaha. Hopefully my system will give me the impact I'm looking for. IDQ's 8's will have ohh, 500 watts or so EACH.....

All the drivers I mentioned are hard as heck to find, unfortunately. The 8IB4's are still in production. Look for the JL stealthboxes in BMW's for the most common source. The B&C driver is probably the easiest driver to find that will work well. Dyn 170's have been known to do ok as well.

JonJT
12-30-2006, 11:16 PM
Figured, I'm trying to get some phl 2520's for my midranges 8 inches of midrange, hells yeah! Kicks are going to be half my floor, the other half being some IDQ 8's......hahaha. Hopefully my system will give me the impact I'm looking for. IDQ's 8's will have ohh, 500 watts or so EACH.....

8 inch midrange? jeez, wouldn't such a large driver start beaming at a pretty low frequency?

T3mpest
12-30-2006, 11:25 PM
Being in my kicks, I can afford to put them pretty much on axis. With horns, I won't be running them really high. I can probably get away with 1k or so with a shallow slope. I've seen some 9inchers that won't start really beaming badly until 1.5 or so. Odds are I'll be ok, plus they are 100db effecient and can't handle 200 watts of power (like I'd ever give them that much closer to 50).

JonJT
12-30-2006, 11:43 PM
o, well good luck with that then.

Thnking
12-31-2006, 01:53 AM
Even if a highly efficient woofer has a large cone and great pistonic movement, it still not be that great at reproducing low frequencies?
Large is relative to the audio industry standards. 18" cones have large air load impedances, a 100hz wavelength is over 11'. The same goes for the speakers displacement, it's relative to industry standards and design linearity limitations. Typically as displacement increases, distortion increases. As displacement increases non-linearities in parameters increase.

djdilliodon
12-31-2006, 02:49 AM
thats def a wrong figure.

its eaither 15mm 2 way or not right at all. theres no way an 8" will be doing 30mm of movement and keep up the transient response for midbass action...

i just cant see it.

any pics of these cdt hand built thingies?


The xmax figure i was told is 15mm and believe me they move. I have a vid of them you can see here http://www.realmofexcursion.com/videos/CDT%20Audio/es-06+.1.wmv each mid is seeing around 90wrms or less full range. Oh and these are not 8's they are 6.5's :)

squeak9798
12-31-2006, 11:49 AM
So far I would have to agree with what most of the others have said.

Transient response is dictated by inductance and the final system Q of the driver. Sensitivity, as was pointed out, is simply amplitude in relation to input power.....and high sensitivity and low frequency extension don't get along very well. Due to that stinking law Hoffman identified, high sensitivity midbass drivers are going to need large airspace (and possibly need to be ported) to have good authority in the lower frequencies. The main saving grace in car audio is the reasonable amount of transfer function gained by the enviornment. This could be enough, depending on the vehicle/etc, to extend the low end response by a reasonable margin.

But, it really depends on who you talk to. There are many who subscribe to the high sensitivity ideology when mating drivers with horns. There are those on the other side of the fence who don't consider this a mandate (atleast for dedicated midbass). Look at the Team ID guys....how many of them are using a midbass with a sensitivity higher than 92-93db? Heck, the IDQ8 is the #1 recommended mid to use with horns....and it comes in at 90.8db.

Overall, I would have to say that for a dedicated midbass like you are wanting....I would have to agree with Helotaxi to find a midbass with low distortion and good displacement and feed it power.

joe duce
12-31-2006, 06:40 PM
The xmax figure i was told is 15mm and believe me they move. I have a vid of them you can see here http://www.realmofexcursion.com/videos/CDT%20Audio/es-06+.1.wmv each mid is seeing around 90wrms or less full range. Oh and these are not 8's they are 6.5's :)

:eek:
what kinda mounting depth do these have? i too am looking for some nice midbass to mate with horns but i want something with a small mounting depth so i do not have to carve up my door panel.

joe

djdilliodon
12-31-2006, 06:50 PM
Depth on the 06+ is just under 3.5".

T3mpest
12-31-2006, 07:25 PM
So far I would have to agree with what most of the others have said.

Transient response is dictated by inductance and the final system Q of the driver. Sensitivity, as was pointed out, is simply amplitude in relation to input power.....and high sensitivity and low frequency extension don't get along very well. Due to that stinking law Hoffman identified, high sensitivity midbass drivers are going to need large airspace (and possibly need to be ported) to have good authority in the lower frequencies. The main saving grace in car audio is the reasonable amount of transfer function gained by the enviornment. This could be enough, depending on the vehicle/etc, to extend the low end response by a reasonable margin.

But, it really depends on who you talk to. There are many who subscribe to the high sensitivity ideology when mating drivers with horns. There are those on the other side of the fence who don't consider this a mandate (atleast for dedicated midbass). Look at the Team ID guys....how many of them are using a midbass with a sensitivity higher than 92-93db? Heck, the IDQ8 is the #1 recommended mid to use with horns....and it comes in at 90.8db.

Overall, I would have to say that for a dedicated midbass like you are wanting....I would have to agree with Helotaxi to find a midbass with low distortion and good displacement and feed it power.

91 db's while not hyper efficient, is still much better than alot of midbasses out there. I'd say a idq is highly regarded for midbass duty becuase it's somewhat effecient and still has good linear excursion values.

squeak9798
12-31-2006, 07:35 PM
I'd say a idq is highly regarded for midbass duty becuase it's somewhat effecient and still has good linear excursion values.

5mm rated.....not hard to find a mid with comparable efficiency and the same or more excursion. That's not to say that it doesn't have great tonal characteristics/etc that make it "all the rage"....but from an efficiency and linear excursion point of view; it's nothing special or extraordinary in either category. As such, it's not hard to find something comparable spec wise.....and you don't need something 95db+

helotaxi
12-31-2006, 09:37 PM
If you are talking about using 8ohm midbasses with 8ohm horns, they'd either better be efficient or seeing a lot more power. If you substitute a 2 ohm mid you could get away with matching a 89dB woofer with a 96 dB horn and they would blend realtively well for the simple reason that you could run the same amp and theoretically push 4x the power to the mid. 4x the power gives you 6dB more output. Double up the mids if you are really worried about it for another 6dB gain.

JonJT
01-05-2007, 04:58 PM
Large is relative to the audio industry standards. 18" cones have large air load impedances, a 100hz wavelength is over 11'. The same goes for the speakers displacement, it's relative to industry standards and design linearity limitations. Typically as displacement increases, distortion increases. As displacement increases non-linearities in parameters increase.

Yes it is relative, so let me be more specific. When I said large, I meant large in comarison to the "average" midbass woofer. Something that has a bit more displacement than the average midbass woofer yet has 6 or more dbs of efficiency at 1 meter away with 1 watt of power. Like, say an 8 or 10 inch woofer with 250 cubic centimeters or more of cone area and 8+mm of linear cone movement in one direction. Assuming such a woofer had 94+db efficiency at said distance with said power why would such a woofer be at a disadvantage when reproducing lower frequencies?

I don't see why higher sensitivity hampers low frequency capabilities.

JonJT
01-05-2007, 05:03 PM
So far I would have to agree with what most of the others have said.

Transient response is dictated by inductance and the final system Q of the driver. Sensitivity, as was pointed out, is simply amplitude in relation to input power.....and high sensitivity and low frequency extension don't get along very well. Due to that stinking law Hoffman identified, high sensitivity midbass drivers are going to need large airspace (and possibly need to be ported) to have good authority in the lower frequencies. The main saving grace in car audio is the reasonable amount of transfer function gained by the enviornment. This could be enough, depending on the vehicle/etc, to extend the low end response by a reasonable margin.

But, it really depends on who you talk to. There are many who subscribe to the high sensitivity ideology when mating drivers with horns. There are those on the other side of the fence who don't consider this a mandate (atleast for dedicated midbass). Look at the Team ID guys....how many of them are using a midbass with a sensitivity higher than 92-93db? Heck, the IDQ8 is the #1 recommended mid to use with horns....and it comes in at 90.8db.

Overall, I would have to say that for a dedicated midbass like you are wanting....I would have to agree with Helotaxi to find a midbass with low distortion and good displacement and feed it power.

Reading hoffmans iron law basically explained it to me.
My understanding tells me that a highly efficient woofer isn't incapable of playing low frequencies with authority, but just needs an extremely large enclosure to do it, is this correct?

In this case, using an old "run of the mill" high displacement midbass along with a seperate high efficiency midrange would be the best bet. I think I will purchase that audax woofer and just canibalize my dual Koda 8 home subwoofer and use those woofers for midbass duty. Thats a hell of a lot cheeper than buying something compairable

JonJT
01-05-2007, 05:11 PM
If you are talking about using 8ohm midbasses with 8ohm horns, they'd either better be efficient or seeing a lot more power. If you substitute a 2 ohm mid you could get away with matching a 89dB woofer with a 96 dB horn and they would blend realtively well for the simple reason that you could run the same amp and theoretically push 4x the power to the mid. 4x the power gives you 6dB more output. Double up the mids if you are really worried about it for another 6dB gain.

I'm gonna use Koda 8's. Not all that efficient but its got a lot of mechanical power handling and thermal power handling, last I heard, was good to about 175 watts.

I'll be using an 8 ohm mid. The difference in impedance isn't really going to matter. I'm not going to really see the differences in efficiency until something starts clipping. I'm not sure what amps I'm going to get, but I'm looking at brands that, at the least, produce solid hardware. 50+ watts into an 8 ohmn, 96db horn and a 100db 6.5 inch midrange is going to produce dangerously high sound pressure levels. No way I'm going to listen at even a quater of that power output. And I doubt any of the amps I use are going to clip at even 25 watts countious output. I'm not so worried about the differences in efficiency anymore. The woofer of lowest efficiency is still going to be way to loud for me to listen before the amps start to clip, the woffer exccedes its mechanical limit or the voice voils fry.

squeak9798
01-05-2007, 11:12 PM
Reading hoffmans iron law basically explained it to me.
My understanding tells me that a highly efficient woofer isn't incapable of playing low frequencies with authority, but just needs an extremely large enclosure to do it, is this correct?

Theoretically; yes.

However, a majority of high efficiency drivers are also low Q, high Fs and low excursion drivers......as such, most need to be ported or horn loaded to really maximize the driver's low frequency output/extension.


In this case, using an old "run of the mill" high displacement midbass along with a seperate high efficiency midrange would be the best bet. I think I will purchase that audax woofer and just canibalize my dual Koda 8 home subwoofer and use those woofers for midbass duty. Thats a hell of a lot cheeper than buying something compairable

Sounds like a pretty good plan to me.

Thnking
01-05-2007, 11:58 PM
Yes it is relative, so let me be more specific. When I said large, I meant large in comarison to the "average" midbass woofer. Something that has a bit more displacement than the average midbass woofer yet has 6 or more dbs of efficiency at 1 meter away with 1 watt of power. Like, say an 8 or 10 inch woofer with 250 cubic centimeters or more of cone area and 8+mm of linear cone movement in one direction. Assuming such a woofer had 94+db efficiency at said distance with said power why would such a woofer be at a disadvantage when reproducing lower frequencies?

I don't see why higher sensitivity hampers low frequency capabilities.

Below you say you do...?

An easy way to understand it is- higher sensitivity drivers have greater energy dissipation. As we increase energy dissipation we reduce resonance.

Remember, air load is relative to wavelength vs propagating surface area. Increasing the SA a small proportional number isn't going to reduce air load significantly to increase sensitivity.

JonJT
01-06-2007, 02:10 AM
Below you say you do...?

An easy way to understand it is- higher sensitivity drivers have greater energy dissipation. As we increase energy dissipation we reduce resonance.

Remember, air load is relative to wavelength vs propagating surface area. Increasing the SA a small proportional number isn't going to reduce air load significantly to increase sensitivity.

Yes, I responded to your post, then did some research and didn't edit what I sadi to you, sorry.