Relative newbie has question about ports and passive radiators

[Pandaman617]

Hi guys, quick question. I rotate Mirage OM-10’s, OMD-28’s and Omni 260’s as my mains depending on my mood and CC being used. The Omni’s use a pair of 6.5” woofers with a front firing port. I’ve always wondered if I could replace the port with a passive radiator. I’m starting to look into doing my first pair of DIY speakers so I know this is a fully loaded question but I’m just curious if it’s a waste of time or if it could help them a little in the low end department. They’re rated at -/+3dB @ 35hz and I’m running them off a 200 WPC amplifier but I do run them as small and cross them over at 80hz. Really I’d just want to do it to see if they sound a little better in the bass department. My OMD-28’s sound amazing with that amp and blow the Omni’s out of the water as far as low end response goes but they were also much more expensive retail wise. Anyways, if it’s a stupid idea I apologize and I don’t want to annoy anyone I just haven’t been able to find an answer on my own. Thanks in advance guys!

 

[mazersteven]

 

[flippo]

Not a Good idea

 

[lovinthehd]

If you could figure it out you probably wouldn't be asking....

 

[everettT]

Hi guys, quick question. I rotate Mirage OM-10’s, OMD-28’s and Omni 260’s as my mains depending on my mood and CC being used. The Omni’s use a pair of 6.5” woofers with a front firing port. I’ve always wondered if I could replace the port with a passive radiator. I’m starting to look into doing my first pair of DIY speakers so I know this is a fully loaded question but I’m just curious if it’s a waste of time or if it could help them a little in the low end department. They’re rated at -/+3dB @ 35hz and I’m running them off a 200 WPC amplifier but I do run them as small and cross them over at 80hz. Really I’d just want to do it to see if they sound a little better in the bass department. My OMD-28’s sound amazing with that amp and blow the Omni’s out of the water as far as low end response goes but they were also much more expensive retail wise. Anyways, if it’s a stupid idea I apologize and I don’t want to annoy anyone I just haven’t been able to find an answer on my own. Thanks in advance guys!

Ports and passive radiators are virtually the same thing, no improvement. If you want improvement in the bass dept, up your crossover or get a better sub.

Edit: what sub

 

[Pandaman617]

After further research this was a stupid idea and will not be even remotely attempted.

 

[Pogre]

After further research this was a stupid idea and will not be even remotely attempted.

Lol. Yup.

I was going to ask... were you planning to cut out a giant hole in the cab to fit a passive radiator? Actually, I think you'd need 2 of them. Or 1 big racetrack one. Pretty sure you need to double the surface area of the cone with the radiator(s) to work right. Then rework the crossovers, brace the cabinets better...

Anyway. Yup. Not a good idea, and you'd likely render the speakers unlistenable and irreparable in the process.

 

[TLS Guy]

After further research this was a stupid idea and will not be even remotely attempted.

I'm glad you figured that out. The F3 of a QB4 ported box is the same as the ABR box with the same driver. However the port will roll of at 24 db per octave and the ABR box at 36 db per octave. So if you carried out your plan you would have less low bass.

So what is the point of an ABR box. Well it is useful if the port dimensions are too big for the box, or if the port is so long port resonance is an issue where the port acts as an open pipe, and that frequency falls in range in which the driver is operative. Also marketers like it as it makes the speaker look more impressive to the ignorant, who then think the speaker is better as it has this big bass driver. The latter is probably the commonest reason for its use except in subs.