New box or new sub/amp?

[Terrum 10+ year member]

I currently have a Rockford R750-1D amp and an Orion XTR152D sub with this ported box https://www.ebay.co.uk/itm/262891168376. The seller said that the box was tuned to 42hz. Being a newbie I had no idea the calculations involved to ensure my sub's driver could actually handle the box's tuning, or what kind of box I should've even got. I just got a ported one because they require less power than a sealed box.

So my first question is, what would be the best way to find out what box tuning would be best for my sub? My second question is, would I be able to achieve a 25-30hz tuning with my current sub and amp if I got an appropriate box or will I need to invest into a new sub and amp as well?

Any help is greatly appreciated!

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[OldFartAudio]

Unless the seller designed the box specifically for your sub then saying it is tuned to 42 hz is inaccurate. The speaker's measurements must be used to determine the box design. You can build a box to your desired specs but you need to know the Thiele measurements of your sub. They should be listed in the manual or on the Orion website. If you are shooting for 20 hz you may need to build a very large box to do so. Typically the larger the box the lower the tuning. I am an advocate of sealed boxes because they are more forgiving than ported boxes as far as design goes and they play deep in a car. The catch is they need more power to get as loud. I am not an expert in box design software but you can get software that lets you put in your sub's specs and it will tell you what boxes will work best. You can also plug in what you want to achieve, tuning wise, and it will tell you the box dimensions you need to get that. Good luck with it and have fun tuning.

 

[hispls 5,000+ posts]

That box is about half the size you would want for a 15" woofer. It's even a little on the small side for many 12s. What music do you listen to that you feel you would need to tune to 25hz?

 

[Terrum 10+ year member]

Thanks a lot for the replies!

@OldFartAudio Very informative, I really appreciate it

@hispls With the current setup I can achieve about 35hz and still feel it, I'm probably asking for too much but I'd like to be able to feel the lower notes in my songs of choice (using a spectrum analyzer software, some songs go down to 28hz).

I have no tools for DIY or making my own box unfortunately, so perhaps someone in the UK can recommend me a person/business that offers such a service?

By the sounds of it I'm probably asking for too much, as I can't really fit a bigger box in my trunk

 

[hispls 5,000+ posts]

I have no tools for DIY or making my own box unfortunately, so perhaps someone in the UK can recommend me a person/business that offers such a service?

Well, with a cordless drill, a jigsaw, and a caulking gun you could possibly pay a lumber yard a small fee to cut your pieces for you and assemble yourself. Or reach out to a proper cabinet maker who may be able to do the whole thing or at least cut pieces for you. Otherwise I really don't know how many active members we have here from the UK.

Certainly you can make that sub play 28hz loud but possibly at the expense of everything else and not very efficiently particularly if you can't find a lot more volume. What's worse is you're likely very limited in access to different equipment.

It looks like the box you have is the Orion reccomended, but typically these companies lie about how much space you need because the average bonehead thinks that bigger is better and will opt for the biggest thing that they think they can shove into whatever space they think they have.

Really I'd expect if you could get your box up to 4 cubic feet net, 50-60 square inches of port area and keep tuning around 40hz it would probably do well overall and be able to play down to 32ish. Assuming that Orion sub has 2.5" diameter coil it should be pretty hard to hurt it with only 700w amp.

My top suggestion would be if you only have 3 cube to work with and care to be able to play really low and maintain any output anywhere else you'd do better picking a 12" sub, though the ones I can think of that would get you there are on the pricey side here in the USA and would likely be awful after you paid for freight and taxes to get them over there. If you want to see what happens for tuning lower with what you have, see if you can't find some PVC pipe to replace the 4" round port you probably have and just start testing different length ports. Either way, I'd encourage you to think of a way you can adjust port length down the road if you discover you don't like overall response of the system once you get the tuning frequency very low.

 

[nauc 10+ year member]

that sub likes sealed boxes. if you want to run ported, id get a different sub. i like Fi subs for the $

tip...

• EBP - The efficiency bandwidth product, a rough indicator measure. A common rule of thumb indicates that for EBP>100, a driver is perhaps best used in a vented enclosure, while EBP<50 indicates a sealed enclosure. For 50<EBP<100, either enclosure may be used effectively.

to find EBP, divide Fs by Qes

more about TS Parameters...

Thiele/Small parameters - Wikipedia

en.wikipedia.org

 

[Terrum 10+ year member]

Thanks a lot for your replies and apologies for any delay!

@hispls The enclosure doesn't look like it uses any sort of tubing I'm familiar with, just looks like a large slit then it goes around to the back of the sub. Would adding a tube allow me to adjust the port length or should I just forget this enclosure and look into getting someone to make a proper/better one for me?

Many thanks for everything so far!

 

[hispls 5,000+ posts]

The enclosure doesn't look like it uses any sort of tubing I'm familiar with, just looks like a large slit then it goes around to the back of the sub.

That's a slot port. Still probably inadequate port area as are most prefab boxes. Round would have been easier for you to fiddle without a big investment.

Hate to break it to you, but a proper box is like 80% of the battle here, hopefully there's someone on your side of the Atlantic that can do something for a reasonable price.

 

[Terrum 10+ year member]

That's a slot port. Still probably inadequate port area as are most prefab boxes. Round would have been easier for you to fiddle without a big investment.

Hate to break it to you, but a proper box is like 80% of the battle here, hopefully there's someone on your side of the Atlantic that can do something for a reasonable price.

I assumed that was the case, no problem at all and thank you so much anyway!