[Eatmore Bacon]

I am preparing to install a front sub for midbass duties covering somewhere in the neighborhood of 50-100 Hz. Air volume is .3 but may take up slightly more floor space than I want to give up. This has brought me to consider IB. Driver choices are Dayton 10” RSS265HO-4 and JL Audio 8W3V3-4. I have read numerous threads that talk about the differences in low frequency between IB and sealed but not about midbass range frequencies. Also, it’s my understanding that a sealed enclosure affords more cone control. So will the IB option not be as “tight” as the sealed in the upper ranges?
Finally, if a sub isn’t listed as IB approved in its specs, what makes on acceptable for an IB application?

Thanks for the continuing education.

 

[Grinder]

I would not recommend using the Dayton 10” RSS265HO-4 IB. It's a low-Q, small-box sub, so it needs a small sealed (or ported) air volume to control excursion and raise Q.

I have no familiarity with the JL 8W3V3-4, so I have no idea whether or not it would be suitable for IB.

 

[Eatmore Bacon]

I would not recommend using the Dayton 10” RSS265HO-4 IB. It's a low-Q, small-box sub, so it needs a small sealed (or ported) air volume to control excursion and raise Q.

I have no familiarity with the JL 8W3V3-4, so I have no idea whether or not it would be suitable for IB.

Thanks, Grinder. You just saved me a lot of agony😂.

 

[Grinder]

I'm certainly no expert, but for 50 - 100 Hz from a subwoofer (rather than low frequency extension), I'm thinking a high-Q setup would work best (typically achieved with a small box), so for IB you'd be looking for a sub with an especially high Qts

 

[Eatmore Bacon]

@Grinder The HO is .35 and the JL8 is .467. What do you call high Q? .6? .7?

 

[Grinder]

Yes, .6 - .8 Qts ... Higher, the better. I really don't know what you're likely to find, but you're barking up the wrong tree looking at small-box subs like Dayton HO and that JL (for which Crutchfield recommends 0.3 ft^3) for IB.

I recommend doing what you can to fit a small box. Remember, for 50 - 100 Hz you don't need low frequency extension, so smaller than recommended volume will be fine.

 

[Eatmore Bacon]

Yes, .6 - .8 Qts ... Higher, the better. I really don't know what you're likely to find, but you're barking up the wrong tree looking at small-box subs like Dayton HO and that JL (for which Crutchfield recommends 0.3 ft^3) for IB.

I recommend doing what you can to fit a small box. Remember, for 50 - 100 Hz you don't need low frequency extension, so smaller than recommended volume will be fine.

So, if I understand you correctly, what you recommend is a high QTS sub in a small sealed enclosure. It seems the higher the QTS the larger the recommended enclosure but I understand it can be reduced due to the frequency range. I don’t believe the JL will achieve what I’m looking for simply due to the smaller cone area. There is the probability of choking subs down to no response as I have experienced that with my original HAT midbass 7’s in kick pods at the beginning of my build. I believe the size was around .18 cu ft. This is proving to be somewhat difficult to say the least.

 

[Grinder]

So, if I understand you correctly, what you recommend is a high QTS sub in a small sealed enclosure. ...

No, that is not at all what I'm saying.

High Qts sub for midbass response in IB application.

Low Qts, small-box sub for midbass response in small box application.

If you must go IB, I recommend the former. If you can manage to find a way to fit a small box, then I recommend the latter.

 

[Eatmore Bacon]

Ah, my apologies. I clearly understand now. Thanks for getting me on the right path.

 

[lithium]

Not sure if it really matters what the QTC is when you're HPF at 50 for this sub. You're above Fs by almost an octave..

excursion is fine @ 600 watts

If IB doesn't work you can use and AP vent to control qtc.

Scanspeak 290001 Aperiodic Vent (SSV)

Scan-Speak Flow Resistor Aperiodic Vent - EACH Cutout size is 4.3 inches. Product picture demonstrate the front and back side of these vents. They are sold each, so order two if you require a pair. Aperiodic vents lower the Q of your driver in a sealed box. They essentially makes your sealed box...

www.madisoundspeakerstore.com

.

 

[Grinder]

Not sure if it really matters what the QTC is when you're HPF at 50 for this sub. You're above Fs by almost an octave..

View attachment 364575

excursion is fine @ 600 watts
View attachment 364576

If IB doesn't work you can use and AP vent to control qtc.

Scanspeak 290001 Aperiodic Vent (SSV)

Scan-Speak Flow Resistor Aperiodic Vent - EACH Cutout size is 4.3 inches. Product picture demonstrate the front and back side of these vents. They are sold each, so order two if you require a pair. Aperiodic vents lower the Q of your driver in a sealed box. They essentially makes your sealed box...

www.madisoundspeakerstore.com

.

Excellent point. Not sure how I missed that. If I had thought to model it with 50 Hz HP applied, it would have smacked me in the face.

Still, I figured some box rise may come in handy.

 

[Eatmore Bacon]

@lithium I have to say thats pretty interesting. I took my truck to my fabricator today. Listened to two different stored tunes, original and HP. He agreed with the solution of adding a single sub for the mid bass application, especially given how my doors are constructed. We developed a plan to make a mold and measure for an accurate air volume with water. He did not think the IB was a good idea based on what I wanted to achieve, no matter what driver I used. These vents add a very good option should I need to go slightly under .3 cu. ft. I was already going to stuff it with poly fill. I honestly believe it should be right at .3 or a little over. I will know for sure early next week. Thanks for chiming in!

 

[Eatmore Bacon]

So I assume that when a sealed enclosure is too small the driver creates air pressure into limited air volume basically restricting the driver mechanics?

 

[Grinder]

0.3 ft^3 is not too small for that Dayton (or for that JL, according to Crutchfield), and going a bit smaller than 0.3 will not be not an issue, particularly for 50 - 100 Hz.

 

[Picassotheimpaler]

If you keep your q below 1 using a subwoofer in the range you play, you should be fine. Depending on the transfer function of the car, a higher q peak may actually be a bit of a benefit

 

[lithium]

So I assume that when a sealed enclosure is too small the driver creates air pressure into limited air volume basically restricting the driver mechanics?

yep, like an air spring.

 

[dumdum]

Look at a faital pro 10fe200 8ohm… xmax is low but you’re not playing 20hz… 50hz is a picnic with 5.5mm, I cross mine at 50 and I’m not shy with the volume control 🙃

 

[Eatmore Bacon]

Look at a faital pro 10fe200 8ohm… xmax is low but you’re not playing 20hz… 50hz is a picnic with 5.5mm, I cross mine at 50 and I’m not shy with the volume control 🙃

Thanks, dumdum. I'm going to stay with the HO-10 for now and see what the response is like in the sealed enclosure. Great price point!

 

[Gill]

faital pro 10fe200

4 ohm equally good or sticking to 8 Ohm is crucial? @dumdum