I'm adding a set of 8" midbass to my doors to augment the output of my BA comps, and was thinking of a 50-500Hz 12dB/oct bandpass x-over.
Does anyone have experience with passive bandpass x-over points?
I'm OK with the actual selection of parts and x-over fabrication, just not sure about selecting the x-over points etc.
(Would a 50'ish Hz low-pass cutoff be as effective, also making it a lot less complicated?)
Thanks!

 

50 is probably a good high pass for them but 500 is likely too high. More like 200-ish.

I would very much consider a dedicated amp for these. Way easier to dial in the crossover points actively. Level balancing is really tough with passives as well.

 

Thanks Paul. Looks like I'll try using a combination of HU high-pass and active x-over low-pass or a couple coils to get this right, and be able to dial it in, all using the ol'Alpine 3539 which has nice ooomph as a bonus. Sigh, another amp to wire up/find room for.(nice problem to have)

 

Exactly - use the LP on the amp and the HP on the deck. Easy, free bandpass filter.

3539 is a great amp from IMO their best looking series of amps. I have three 3544s sitting on a shelf waiting for something special to go into.

 

Why is mid bass totally missing from the Car Audio industry? Its impossible to listen to metal properly in Cars. LOL. The only thing I can seem to find out about is the Kicker RMB8s which are discontinued and hard to find. And even more impossible to find is the Phoenix Gold 9m midbass. What is wrong with this industry?

 

8"+ drivers don't fit well in most car doors.

I have no problem with the amount of midbass in my car. It takes power and some attention to the install to make good midbass.

 

Attempting to compensate for the problem of 8-inch mid bass installation and car door size/paneling issues through other means will not produce the same accuracy and tightness in response that 8-inch and 9-inch drivers are specifically designed for. And increasing the crossover to the sub to a higher frequency will only sound muddy. Not reccommended. And 6.5s or 5.25s just can't do it. 100 watts RMS into a 6.5 or 5.25 will just not cut it. THis is why the Phoenix Gold Titanium elite 951 set added the 9 inch. It was a heavy 350 watt RMS mid bass driver at 9 inch.

 

^^x2. I have no issues with the midbass in my car either. It's tight, clean, snappy..I like a lot of rock as well. I guess everyone has their idea of what enough midbass (and I guess highs, bass, midrange as well) sounds like, but for me it's very well balanced...I have no desire to add larger speakers to my doors (which I can easily do if i want to).

 

100W into a well installed 5.25 or 6.5 as part of a balanced system certainly CAN do it. Not sure why you think it can't

 

Yet many seem to get fantastic midbass with 5.25 or 6.5" drivers. Amazing..

Attempting to shoehorn an 8" or larger driver into your door when a 6.5 is more suitable for the space available is often a recipe for disappointment.