PA385S build

1st build. Putting together a sub (or two) for the occasional party. For now these will be powered off a Crown DSi 1000. Should be most often used with a set of Mackie SRM450's.

Originally aimed for a 37hz tune from a 22"L x 4" x 16" port in a 4.5cf box. Measurements showed a 32hz tune. Cross over at 65-70hz it sounded great. Loved the low end extension, although it was lower than needed.

Took the port down 5" to gain some db and now measures 34hz port peak. Nearfield plots below. Blue is 22" port. Red is 17" port. There is a patio party this weekend so I'll leave it as-it is for now.

This is a learning experiment, as long as its usable I'm successful. So far it seems very usable.

A few questions:
1. Should I continue shortening the port?
2. I have a second driver and don't mind experimenting, is there a better box configuration for this sub resulting in more sound without loosing much or any low end extension?
3. I have other plans for this Crown. Whats the best bang for the buck solution to power this. I see used amps now and then, but whats the most economical way to implement a HP/LP?
 

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Last edited:

kipman725

Member
Paid Member
2007-06-10 12:41 pm
Warrington
I wouldn't shorten the port anymore as quite a lot of content goes down to 40Hz.

Your crown has built in filters. The most economical way of crossing over would be to adjust the bass to minimum on the SRMs and measure their resulting bass frequency response. Then match the slope with the sub and apply eq filters on the sub so that the combined output is flat. Downside of this is that your subs are running stereo and that your crossover might not be a normal slope, be too high/low and it's fiddly.

A slightly superior option that's still cheap would be to use a 2nd hand analog crossover unit which has a monon summed bass output for the subs. You will also need a XLR splitter and gender changer if your not running the amp mono.

Best way would be to get a digital loud speaker management system however these are often expensive. If you can deal with technical complexity I use a symetrix symnet 8x8 DSP that can often be purchased cheaply 2nd hand.
 
I wouldn't shorten the port anymore as quite a lot of content goes down to 40Hz.

Your crown has built in filters. The most economical way of crossing over would be to adjust the bass to minimum on the SRMs and measure their resulting bass frequency response. Then match the slope with the sub and apply eq filters on the sub so that the combined output is flat. Downside of this is that your subs are running stereo and that your crossover might not be a normal slope, be too high/low and it's fiddly.

A slightly superior option that's still cheap would be to use a 2nd hand analog crossover unit which has a monon summed bass output for the subs. You will also need a XLR splitter and gender changer if your not running the amp mono.

Best way would be to get a digital loud speaker management system however these are often expensive. If you can deal with technical complexity I use a symetrix symnet 8x8 DSP that can often be purchased cheaply 2nd hand.

The crown works great for now. I have other plans for it so looking for alternatives. I don’t see many DSP amps on the used market. I’ll keep an eye out for an analog crossover.
 
1.) What a good portable'ish enclosure for the second sub - bandpass, keystone? I haven't found many builds out there with these subs.

If no suggestions, the next box will be another ported 3.75-4.0 cuft tuned ~40hz as a trial to see if loosing some more extension is worth the 2-3db increase between 45-70hz.

2.) How bad is it to overlap sub and mains? The mains only have a 75hz HP on/off. the current sub "blends" well if crossed at 65 or 70 @ 12db. I'd like to raise that but thought it could cause issues.