Adequate Crossover frequency of Peerless 835017?

[Peter Huang]

I know this driver is categorized as a “subwoofer”. The typical subwoofer is operated below 120 Hz. However, the frequency response diagram of peerless 835017 shows that it could be flat to about 1 KHz, as attached.

Could I set its low-pass crossover frequency up to 1Khz?

Thanks a lot for your kindly comment and suggestion?

 

[bbggg]

No. There is beaming up there, and you had better stay well clear of that horrid bell mode at 3 kHz. I'd say at least two octaves away with an LR4, and take a good look for detailed harmonic distortion charts, as that bell may be upset by sneaky fundamentals further down. Nah, three octaves down is probably best.
Done your way, the only reasonable use would be in a two-way with a compression driver and horn for the upper spectrum. There may be a severe sensitivity mismatch to be dealt with, and particular care should be lavished upon polar response uniformity.
In a direct radiator 3-way it would be rather outlandish to cross a 12"er that high, when there should be a perfectly suitable driver for mid duty.

 

[Moondog55]

right in the centre of the FLAT area is where most beginners are advised to start designing XOs, 300 to 500 should be perfectly OK

But WTH if you use Electronic crossovers you can experiment to your hearts content, 4th order at 1k may be OK

 

[Michael Chua]

Could I set its low-pass crossover frequency up to 1Khz?

It's not advisable. You can see from the plot that the cone breakup starts at 1K. I would cross 1-2 octaves away, ie 500Hz to 250Hz.

Any reason why you need to cross at 1KHz?

 

[Peter Huang]

Thanks a lot for all your helpful advice.

I want to make some experiments to explore the 835017's whole potential performance and find possible best crossover frequency to match some my Horn speakers. It maybe a tough job.

I may design 4th order active lowpass/highpass filters with variable frequency settings. Possibly 12 values of 1/3 Octave Band Frequencies are 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, and 800Hz.

 

[Michael Chua]

I find that "Subwoofers" work best below 50Hz. When I try to make them do Mid-Bass (100Hz region), they fall flat. Don't have the attack and definition that I expect.

My solution is to treat mid-bass separately from sub bass. Use one woofer for mid-bass and if needed, a separate one for sub.

I am also looking for a woofer to go with my horns, the JBL 2342 Bi-Radials. This 10" by Seas ( CA26RE4X ) looks promising. It will allow me to cross at 1K to 1K5.

 

[Peter Huang]

Thanks, Michael. I highly appreciate your suggestion of JBL 2342.

I have already completed a pair of sealed cabinets for the 835017 with Qtc=0.7.
I just test them alone by a heavy drum program. The sound is quite fantastic.
The subwoofer controller is still under construction.
Please forgive my crazy idea.
The synergy of subwoofer and main horn speaker to a high crossover frequency should be quite difficult.
I may report the test latter.

Cheers!

 

[bobodioulasso]

I find that "Subwoofers" work best below 50Hz.

i am experiencing the same.
i use a 12xxls subwoofer combined to a two vay speaker.
(6.5" mid and 2"tweeter)
I run an active system.
it sounds good when crossover is set very low .
When sliding up the crossover point the sound is getting thick.
After struggling i found this:
The sub level being set for good bass when the crossover point at 60hz.
When the crossover point is set at 300hz the output level around this frequency is way too low compared to the output level of the two way speaker at the same frequency range.
So i have to rise the low band level out of my active crossover.
To recover the level of low freq. bass i want, i need to equalize down the low end. (slope from 300 to 60 ending at -6db at 60hz)
the result is tight bass slam.


i conclude that a too far a flat response towards the low end, combined with room gain, gives muddy( boomy) bass response.

 

[bobodioulasso]

edit:
read 30hz instead of 60

nevertheless i am contemplating to use a plain woofer.
I was thinking about ca26 rfx.
Could you comment your choice CA26re4x?

 

[Peter Huang]

I would like to explain further.

I have already designed a low pass filter system crossovered by 1/3 octave bands at 30, 39, 44, 50, 56, 63, 70, 79, 88, 99, 111, and 125Hz, totally 12 bands, adjusting by rotary switches. This low pass system also has the feature of LR transformer, equalizer and all pass filter, etc. In such condition, I treat the peerless 835017 as a typical subwoofer.

However, I found that the driver's frequency response could be flat to about 1K Hz. So I maybe able to explore its possible potential performance to be as a woofer. I have already made two cabinets. So I would design a extra low-pass/high-pass filter system with crossover frequency setting adjustably at 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800 and 1KHz. The low-pass part of the system is used to control the 835017, while the high-pass filter is used to controll the main speaker. Without the high pass filter for the main speaker, the bass will be too thick, as bobodiolasso worried. Since the sound beyond about 100Hz is quite directional, this system should be stereo, or 2 channels. The low-pass/high-pass filters is designed to be 4th order slope. This is my idea to explore the driver's performance. Because I am just getting into the field of subwoofer, I maybe quite wrong or studpid.

Thanks again for all your helpful comments or suggestion.

Regards,

 

[bbggg]

At least you'll be able to test every combination to your heart's content, provided you equalize correctly, and you'll decide for yourself what you like the best. The higher you cross the 835017, the more maximum loudness you'll be getting out of the system. The question is, how will a crossover point sound smack dab in the middle of the vocal range? Sometimes it is worth sacrificing some loudness to improve homogeneity, but such matters are often to do with choice of music, or personal tastes and preferences in general.

 

[Michael Chua]

edit:
read 30hz instead of 60

nevertheless i am contemplating to use a plain woofer.
I was thinking about ca26 rfx.
Could you comment your choice CA26re4x?

I chose the re4x because I intend to cross my JBL2342+JBL2425 at 1,200Hz to 1,500Hz. According to their specs, the re4x extends up to 1,500Hz, whereas the rfx is up to 1,000Hz before cone breakup.

I think the 2 woofers are quite similar. The difference is one has better bass performance while the other has more mid-range.

Another reason for choosing the re4x is because it's a SEAS. I'm using their ER18RNX with their 27TDFC in my 2-way Starling. I am truly impressed by the ER18RNX. Very smooth mids and best of all, with an incredible bass definition. With their 10" re4x, I am expecting the same qualities but with a "bigger" sound.

 

[454Casull]

500 Hz at most, depending on the application.

 

[bobodioulasso]

However, I found that the driver's frequency response could be flat to about 1K Hz. So I maybe able to explore its possible potential performance to be as a woofer.

I did what you intend to.
I use ( for two years) two xxls as woofers up to 300hz into 60 liters closed boxes and a state variable 4th order active crossover. So , no overlap.

My feeling is that such a sub is an overkill (though it may depend on the room size, mine is 4m x 5m)


I think a plain woofer using a light cone (36g) such as the Seas would integrate better to my midwoofer (11g cone) in the midbass region. And will produce enough low bass in my room.

I chose the re4x because I intend to cross my JBL2342+JBL2425 at 1,200Hz to 1,500Hz.

Thanks for telling.

The RE4X has a shorter voice coil and 8mm ppXmax only against 14mm for the 26RFX.
It has a smaller magnet too.