High Sensitivity midbass drivers

[djdilliodon 10+ year member]

Depth on the 06+ is just under 3.5".

 

[T3mpest 10+ year member]

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 5,000+ posts]

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 5,000+ posts]

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 10+ year member]

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 10+ year member]

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 10+ year member]

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 5,000+ posts]

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 10+ year member]

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 10+ year member]

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.