Impact of BL / Force factor on SQ

[Steve Lee]

So we come full circle - to solve this we add a separate cabinet, a cross-over and separate amp for the lows, mids and highs, right?

[Steve Lee]

Interesting comparison when considering the Le, MMS and SPL values resulting from the driver specs . . .

Blah1


(How do we use the Equivalent Force value and the SPL, MMS & Le combined as a formula to arrive upon the bestest woofer/midrange or do we need to add Vas to the list?).

I guessed at the Bl of the Denovo Anarchy 704 driver as it isn't a published nor tested value that I can find anywhere on-line . . .

[billfitzmaurice]

Mms has little effect on BL, Le almost none. Qes has the most effect on Bl. This should make it clear why:

https://speakerwizard.co.uk/driver-ts-parameters-bl-motor-strength/

[Billet]

I have also seen people referring to the ratio of BL/Mms as it relates to midrange response. Makes sense to me, as in F=MA. Actually, A=F/M or A=BL/Mms, in this case. It makes sense that higher acceleration increases the bandwidth of a driver, as acceleration relates to frequency. As long as the cone is up to the task, this should result in a wider range of usable sound reproduction.

Eminence provides this data for all of its cone drivers and in my experience, the ratio can be correlated to the frequency response graph.

[Billet]

I think that BL and Qes are directly related, high magnetic force equals more magnetic damping.

BL and Le appear to be indirectly related, a high BL could be from a longer coil (higher Le) or from a stronger magnet.

[fpitas]

I think that BL and Qes are directly related, high magnetic force equals more magnetic damping.

BL and Le appear to be indirectly related, a high BL could be from a longer coil (higher Le) or from a stronger magnet.

Yes, although if they toss in shorting rings all bets are off for Le.

[fpitas]

It has a pretty obvious impact in the time domain. F=ma or a=F/m. BL is measured in Newtons per Amp (or Tesla meters, which is equivalent). That's your force. Mass is Mms. That dictates how fast your cone can accelerate which dictates transient response.

I think you'll find that the frequency response tells the entire tale of transient response. They are linked mathematically. If people don't properly EQ the high BL drivers, as Bill talked about, they will get "better" transient response simply from the rising characteristic with frequency.

[billfitzmaurice]

Transient response is linked with motor strength, but not by how fast the cone can accelerate. It's quite the opposite, in how fast the cone can decelerate to prevent overshoot. Higher Bl drivers tend to have better transient response, but not because they have higher Bl. It's because the motor has more control over the coil and cone, which also tends to result in higher Bl. As for the NE225, PE has them on closeout. They don't do that when demand is high. They do that when demand is too low to justify keeping them.

[fpitas]

Less being pedantic. More buying Peerless NE225, please.

Lol yeah, but no thanks. I'll limp by with my SEAS W18s.

[fpitas]

Lol. You would choose SEAS over Tymphany NE.

A friend has quads of Tymphany 830869s with each of his horns. Very nice sounding. But I chose the W18E001s.

[fpitas]

I'll confess that aesthetics were secondary in our choices.

[fpitas]

I want to sell them commercially, and I don't want them to look like a DIY Frankenstein cringe-fest with mismatched drivers. I want them to look elegant, finished and professional. Considering that the NE225 is a great driver and gives me that, you can understand my choice.

I don't think anyone here has dissed the NE225. It's a very nice driver.

[Chris Roemer]

lucas, why don't YOU ju$t buy 5OO of them (esp. if you'll need a stockpile) ?

[Steve Lee]

Mark your calendars for the 19th.

he'll be baaaack!

:D

[Steve Lee]

Oh, and right on cue, Amps labs is creating a solution similar to the problem Bill had described earlier in this thread --> https://ampslab.com/blog/2021/11/16/osprey12-basseq/

[billfitzmaurice]

I'd rather a DSP that works on more than one frequency. You can't correct in room response with only a 50Hz boost.

[Steve Lee]

^ I understand and agree with you, Bill - I was just pointing out that the sensitivity increase in midrange with pro drivers is an issue and that others are seeking solutions as well.