Eminence 1" N151M-8 for home use

[Music is life]

I know that different horns are going to produce different response and that attenuation would also be needed. That being said how would you go about trying to flatten out this frequency response for home Hi Fi use?

Do you think notch filters might do the job or would it need a combination method? Target crossover would be 1800hz and -3db at 16,000hz.

https://www.parts-express.com/pedocs...ifications.pdf

[jhollander]

After you add in the baffle and depending on how the woofers is low passed a third order x-o would flatten.

[isaeagle4031]

I will be using this CD shortly mounted to a Beta8cx. 3rd order electrical filter and padding is working out nicely thus far.

[jhollander]

I thought you scraped that project?

[billfitzmaurice]

how would you go about trying to flatten out this frequency response for home Hi Fi use?

1/3 octave EQ. Pro-sound drivers tend not to be too concerned about flat response, because pro-sound operators have EQ as standard equipment. For hi-fi use I'd look for a driver with flatter response. It will likely also be considerably less sensitive, but for home hi-fi that's not a bad thing.

[isaeagle4031]

I thought you scraped that project?

No! That was another coax idea. This one is the Beta8cx and N151M8 combo with passive cross with a Definimax 4012ulf on the bottom. Minidsp handling the bottom crossover

[EarlK]

Here's one way to flatten the response .



Clearly, some padding is needed to complete this network.

[Music is life]

Thanks everyone!

Earlk, is that a 3rd order crossover with compensation for High Frequency loss?
Is that set for 1800hz crossover?

You said:
"some padding is needed to complete this network".
You mean an attenuation to match the midrange?

[EarlK]

Thanks everyone!

Earlk, is that a 3rd order crossover with compensation for High Frequency loss?
Is that set for 1800hz crossover?

You said:
"some padding is needed to complete this network".
You mean an attenuation to match the midrange?

It's a 3 pole design ( 3rd order, if you like ) with 2 notch filters.
- FYI, this is a very common topology within the JBL Pro design handbook ( from a couple of decades ago ) .

It doesn't implement the typical HF contour circuit ( RC ).
- Instead, the first capacitor starts the roll-off quite high-up with the other 2 poles producing the lower knee ( at crossover ).
- The value of that first cap will also determine the amount of network attenuation ( if any ) baked into the design .

See this example ( C1 was made smaller for the extra attenuation offered by that choice );




The actual 3db down point from the flat line was originally @ 1450hz ( this is just a spit-ball design / no intent implied !) .
- I'd want to measure a driver on a horn first ( for Fr and distortion specs ) before choosing a crossover point

An Lpad could also have been used to balance this network to some woofer of choice .
- If an 8 ohm ( variable ) Lpad ends up being placed just before the driver / then the LC values will need to be adjusted somewhat to the new load impedance.

[Brian Steele]

Here's one way to flatten the response .

[ATTACH=CONFIG]n1333300[/ATTACH]

Clearly, some padding is needed to complete this network.

Ouch - that looks like another $25~$35 in x-over components, for a driver that cost $75. I wonder how it compares against more expensive CDs that don't require the notch filtering..?

[billfitzmaurice]

I wonder how it compares against more expensive CDs that don't require the notch filtering..?

My point exactly. Instead of using a complicated filter to drop 10dB of sensitivity across much of the pass band find a driver with lower sensitivity and flat response, and if anything probably less expensive. For instance:
https://www.parts-express.com/prv-au...bolt--294-2828

[jhollander]

That PRV looks nice, still a third order and L-pad will do just fine..

[Music is life]

Thanks for all the alternatives.
The PRV does looks nice but in a 90 degree horn, got my doubts on its HF extension, I could be wrong.

My goal is 105-106db, 1800hz crossover, titanium is not first choice.


Earlk, that first one with 105db output is looking good except the crossover point is a little low.
If you have the time and if possible I'd be interesting to look the same thing with a 1800Hz or there about's crossover point or maybe you might recommend a crossover program. Not to oblige.

In any case it's all great info and a lot to think about.

Am not that far off on horn designs for a 3 way high sensitivity satellite. Crossovers are still a weakness.

[EarlK]

Thanks for all the alternatives.
The PRV does looks nice but in a 90 degree horn, got my doubts on its HF extension, I could be wrong.

My goal is 105-106db, 1800hz crossover, titanium is not first choice.


Earlk, that first one with 105db output is looking good except the crossover point is a little low.
If you have the time and if possible I'd be interesting to look the same thing with a 1800Hz or there about's crossover point or maybe you might recommend a crossover program. Not to oblige.

In any case it's all great info and a lot to think about.

Am not that far off on horn designs for a 3 way high sensitivity satellite. Crossovers are still a weakness.

XSim ( by Bill Waslo ) is the network prediction program I'm using here .

For it ( or any other prediction program ) to offer accurate results it needs the drivers frequency response ( & impedance ) inputted as .frd & .zma files .
- Accurate measurements must be made in place ( using attached & mounted horns etc. ) and then the files created by the measurement program .

Here's my last contribution to this thread. It shows the result of moving the crossover a bit higher (@ 2K ) & then tweaking a few other values.
-
You need to understand that unless you're actually using the same ( unknown ) horn that this driver was measured on, this is of quite limited use to you.



The red-line shows the response with both notch-filters in place ( the grey line has the notch filters removed ) .

Pro Audio users would likely simply remove the bumps with DSP filters ( as found in most newer amplifiers > which is something for you to think about ) .

[Music is life]

XSim ( by Bill Waslo ) is the network prediction program I'm using here .

For it ( or any other prediction program ) to offer accurate results it needs the drivers frequency response ( & impedance ) inputted as .frd & .zma files .
- Accurate measurements must be made in place ( using attached & mounted horns etc. ) and then the files created by the measurement program .

Here's my last contribution to this thread. It shows the result of moving the crossover a bit higher (@ 2K ) & then tweaking a few other values.
-
You need to understand that unless you're actually using the same ( unknown ) horn that this driver was measured on, this is of quite limited use to you.

[ATTACH=CONFIG]n1333420[/ATTACH]

The red-line shows the response with both notch-filters in place ( the grey line has the notch filters removed ) .

Pro Audio users would likely simply remove the bumps with DSP filters ( as found in most newer amplifiers > which is something for you to think about ) .

It gives me alternatives and a starting point to work from. It also shows where more work is needed. Thank you.