looking for a "bandpass" crossover.

[mat3833 10+ year member]

ok so i am looking for a crossover to put between my amp and my speakers. the reason i need to do it there and not before the amp is because my amp runs my highs/mids and my sub. there is no internal crossover on the amp as it is quite old but still works very well. SO i need a high/low pass crossover that i can wire into the speaker leads for the sub chanel. this is going in a home theater settup so the high pass needs to be adjustable from about 20hz to 25hz and the low pass needs to be about 100hz to 70hz. i have been looking around and i cant seem to find a combined crosover like this. the only one i found required a 12V power source and was relativly expensive. the power going to the sub is relativly low, only about 50W-100W max but that seems to be more than the crosovers i have found are rated for.

if i can get a fully adjustable crossover with low/high pass and rolloff i would be willing to pay more even if it had to plug into a wall. but everything i have found will nto work for what i need.

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[keep_hope_alive Premium Member]

you need a passive crossover between the amp and speakers/subs. active is for before the amp only. you cannot get an adjustable passive crossover unless it has jumpers and multiple components. it would require adjustable capacitors and inductors, which aren't for this task and aren't this large.

the size of components required for a 25Hz high pass would cost more than a new amp. each cap or inductor would be well over $30 each.

even the components for a 100Hz low pass are large and pricey.

you could just buy a plate amp from ebay or parts express/mcm electronics for $100 or less (with a subsonic filter), and it would be cheaper than the crossover you want to buy/build.

 

[keep_hope_alive Premium Member]

you can buy this low pass (passive crossovers are impedance specific, so you need to know if the sub(s) wire to 8 ohm or 4 ohm.

80 Hz Low Pass 4 Ohm Crossover 266-440

80 Hz Low Pass 8 Ohm Crossover 266-442

due to size/cost, a subsonic filter should be active, and it could be active before the amp. neither the speakers nor woofer need info below 25Hz.

 

[mat3833 10+ year member]

this is for a HT settup so 25hz is relatively high for a subsonic cutoff actually. the reason i havent just bought another amp is because this one is my receiver/amp all in one. i have had it for awhile and love it. the subs are single 8 ohm wired in paralell so the amp sees a 4 ohm load.

Matt

 

[keep_hope_alive Premium Member]

HT subs should be ran off a plate amp. plain and simple.

Dayton Audio SA70 70W Subwoofer Amplifier 300-784

best bang for your buck (and the cheapest one i could find - the higher power amps are even better). a very capable amp. an adjustable sub-sonic filter could go up-stream if your receiver has a LFE output. if not, you could go through a LOC then an active subsonic filter.

20hz high pass Fmod

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-246

 

[mat3833 10+ year member]

ok, i apreciate your help and im not trying to talk crap. but if i am asking for a certain subsonic/lowpass settup it is for a reason. and there is no "rule" that states HT subs should be run ith a plate amp. most high end systems actually use a "rack" amp that is wall mounted. i have a receiver/amp combo that runs exactly what i need with little clutter or extra wires. and saying that no speaker/woofer neeed info below 25 hz is false. 25hz and below is where the real impact of a film comes from. with a few simple measurements my subs will excede their max-x(or X-max) at roughly 1/8th the power they are being fed when they try to play below ~22hz. now if you know anything about home theater/movies in general you know that in most action movies, or any movie with explosions/buildings falling, sound below 22hz is quite common. for example, in the newest transformers movie there are tones(for lack of a better term) ranging from 8hz up in every scene with explosions. since i tend to play my movies quite loud there is a high probability that damage will be done to these subs unless i build some crazy enclosure tuned insanely low.

now i may end up having to simply get an amp specificly for my subs, but since i like my current settup quite alot i really dont want to have to do that. i would much rather just cut off the frequencies below 22hz or even 25hz so that i can continue to enjoy losing my hearing while keeping my subs happy. i was looking at the FMOD's but i dont use RCA's. and that amp is nowhere near the power i would like to have, not to mention being a plate amp it needs to be built into the enclosure for proper cooling.

once again, i apreciate your input and i may end up switching to RCA style inputs. but i would prefer to just add a subsonic filter at the very least. in the end i might just build a new enclosure and get a seperate amp blah blah. but i prefer the simple aproach, and that is an adjustable subsonic filter.

Matt

 

[TheUnderFighter 10+ year member]

Maybe check out some home theatre forums instead? I think you'd find a more knowledgeable user base there man.

 

[mat3833 10+ year member]

home theater forum browsers tend to be pricks. i have asked this question on 3 HT forums and every time my answer was either"build a better box" "get a better sub" or "just blow them". i hoped i might get some real answers on here since CA.com is a nice place to be stupid. lol, it looks like i might just have to get a new amp since i cant find an adjustable subsonic filter.

Matt

 

[hispls 5,000+ posts]

home theater forum browsers tend to be pricks. i have asked this question on 3 HT forums and every time my answer was either"build a better box" "get a better sub" or "just blow them". i hoped i might get some real answers on here since CA.com is a nice place to be stupid. lol, it looks like i might just have to get a new amp since i cant find an adjustable subsonic filter.
Matt

Those seem like reasonable answers IMO. As has been said, building even a fixed point passive crossover would be very expensive.... moreso than a second amp or more capable sub.