HSU VS JTR

[Verdinut]

He's talking specifically about a 2x4 product with Dirac...the other you mention has been around for a while.

I guess I read too fast ! OTOH, a 2 x 4 is not very useful when you want to calibrate a surround system.

 

[Verdinut]

I got my information on this site:

https://www.avsforum.com/forum/155-diy-speakers-subs/1648673-martysub-faq.htmlhttps://www.avsforum.com/forum/155-diy-speakers-subs/1648673-martysub-faq.html

It is a ported 9.0 cubic foot box.

I had figured that because you indicated that the 12 cf box was big at 2 ft wide and 4 ft high, that you had decided to go with a small sealed sub.
But you don't necessarily need a front that size, you can increase the depth instead. You can also make the cabinet wider than high if you prefer.

 

[lovinthehd]

I guess I read too fast ! OTOH, a 2 x 4 is not very useful when you want to calibrate a surround system.

I was thinking just a nice addition for a 2ch setup. Seems better if you already had the 2x4HD and a Umik... Here's some info https://www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24

 

[moves]

I had figured that because you indicated that the 12 cf box was big at 2 ft wide and 4 ft high, that you had decided to go with a small sealed sub.
But you don't necessarily need a front that size, you can increase the depth instead. You can also make the cabinet wider than high if you prefer.

The mini is also ported. If I was to build one, which I am thinking of doing to save money, I was thinking of going ported but haven't 100% decided. Themini marty isn't so mini.. it's 2 by 2 feet ported.

 

[everettT]

The mini is also ported. If I was to build one, which I am thinking of doing to save money, I was thinking of going ported but haven't 100% decided. Themini marty isn't so mini.. it's 2 by 2 feet ported.

The Ultimax driver lends itself to a sealed box more than ported. If you look at the Seaton F18, it's a fairly small box with different preset EQs to achieve the desired extension. Using that driver in a sealed box with a linkowitz transform filter would yield very good extension and SPL. This filter can be applied via minidsp.

 

[moves]

The Ultimax driver lends itself to a sealed box more than ported. If you look at the Seaton F18, it's a fairly small box with different preset EQs to achieve the desired extension. Using that driver in a sealed box with a linkowitz transform filter would yield very good extension and SPL. This filter can be applied via minidsp.

That's what TLSguy was saying as well. Apparently the UM18-22 is not ideal for a ported box. Maybe the RSS460 in a mini marty?

Does anyone know of some instructions on how to build a sealed box? I have the instructions for the marty sub but wouldn't mind looking at some instructions for a sealed one also if I was to go with the Um18.

 

[Verdinut]

The mini is also ported. If I was to build one, which I am thinking of doing to save money, I was thinking of going ported but haven't 100% decided. Themini marty isn't so mini.. it's 2 by 2 feet ported.

I am questioning why you find such a cabinet big when you have a rather big room to install it in. As mentioned in one of my previous posts, you can increase the depth of the cabinet if you want to reduce the front baffle size by respecting the internal volume. With a slotted port, you have to keep the same port area and depth, as the braces act as duct sides. Instead of using pipes, the slotted is indeed a slotted duct to enable you to tune the box to around 20 Hz.

In my apartment, I have three identical front enclosures each measuring 26½" W x 32½"H x 24½"D in a living room of 12½ x 18 feet.

If you want a better subwoofer performance, with more dynamic range, less distortion and a lower frequency reach, you need a vented enclosure. A vented enclosure has to be larger in order to properly perform. The laws of physics and acoustics are inflexible.

 

[Verdinut]

Yea


That's what TLSguy was saying as well. Apparently the UM18-22 is not ideal for a ported box. Maybe the RSS460 in a mini marty?

Does anyone know of some instructions on how to build a sealed box? I have the instructions for the marty sub but wouldn't mind looking at some instructions for a sealed one also if I was to go with the Um18.

Well, Dayton suggest installation of the UM18-22 in a ported box. I know TLS guy's argument against it. The Ultramax's Qts is at the limit for a ported box.

I know the president of Solen very well. They build sub enclosures and I am going to check with Christian about this.

I will get back to you.

 

[moves]

For Frig sakes... I've looked here:

https://www.diyaudioandvideo.com/Calculator/SealedVsPortedSpeakerBox/

and the sealed or ported calculator are recommending both the UM18-22 and the RSS460 as sealed subs... More so the UM18 but still... I've heard of many people using the RSS460 in a ported box and are happy with it.

 

[moves]

Well, Dayton suggest installation of the UM18-22 in a ported box. I know TLS guy's argument against it. The Ultramax's Qts is at the limit for a ported box.

I know the president of Solen very well. They build sub enclosures and I am going to check with Christian about this.

I will get back to you.

Sweet thanks!

 

[everettT]

That's what TLSguy was saying as well. Apparently the UM18-22 is not ideal for a ported box. Maybe the RSS460 in a mini marty?

Does anyone know of some instructions on how to build a sealed box? I have the instructions for the marty sub but wouldn't mind looking at some instructions for a sealed one also if I was to go with the Um18.

The RS Dayton would be better for ported, or the Stereo Integrity 18. For a sealed box, you can certainly use the 4cuf box from parts express.

 

[Verdinut]

I've just talked with Christian.
The UM18-3-22 can be used in a ported box, but you need a beefy amp with a good damping factor to control it's motion. He has several clients using it in such cabinets with good results but not with Crown amps.
I have had a look at specs of the Crown amps. They have a borderline damping factor of >200 but they don't specify for what impedance. We have to assume it's the figure for an 8 ohm load as DF is directly proportional to impedance. This means a damping factor of only >100 at 4 ohms which won't guarantee a good transient response with the heavy moving mass.

However, you would definitely have a guarantee of a tight cone control with the QSC DCA 2422 with a rated power output of 2400W also when bridged. The QSC amp has a damping factor of over 500 which is halved at 4 ohms (>250) compared to one of only >100 for the Crown with the 4 ohm load. Christian is in agreement with me on this.

But the QSC which sells for over $1200 in the US is a lot more expensive than the Crown. If you don't want to spend that much more money on an amp, the solution would be to go for the RSS460HO-4 which is more suitable for a vented enclosure, and easier to control with a less powerful amp.
In a 7.5 cf cabinet, you would be able to get an F3 of 23Hz which I think is adequate and way better than performance in movie theaters, except for IMAX maybe.
Here, a bridged Crown XLS 2002 or even an XLS 1502 would be amply adequate to drive this sub.

The mini Marty enclosure may not be suitable as designed for the 460, because of different Thiele/Small parameters , but if you order from Solen, they will be pleased to give you the appropriate plan for a 7.5 cf vented cabinet.

 

[moves]

I've just talked with Christian.
The UM18-3-22 can be used in a ported box, but you need a beefy amp with a good damping factor to control it's motion. He has several clients using it in such cabinets with good results but not with Crown amps.
I have had a look at specs of the Crown amps. They have a borderline damping factor of >200 but they don't specify for what impedance. We have to assume it's the figure for an 8 ohm load as DF is directly proportional to impedance. This means a damping factor of only >100 at 4 ohms which won't guarantee a good transient response with the heavy moving mass.

However, you would definitely have a guarantee of a tight cone control with the QSC DCA 2422 with a rated power output of 2400W also when bridged. The QSC amp has a damping factor of over 500 which is halved at 4 ohms (>250) compared to one of only >100 for the Crown with the 4 ohm load. Christian is in agreement with me on this.

But the QSC which sells for over $1200 in the US is a lot more expensive than the Crown. If you don't want to spend that much more money on an amp, the solution would be to go for the RSS460HO-4 which is more suitable for a vented enclosure, and easier to control with a less powerful amp.
In a 7.5 cf cabinet, you would be able to get an F3 of 23Hz which I think is adequate and way better than performance in movie theaters, except for IMAX maybe.
Here, a bridged Crown XLS 2002 or even an XLS 1502 would be amply adequate to drive this sub.

The mini Marty enclosure may not be suitable as designed for the 460, because of different Thiele/Small parameters , but if you order from Solen, they will be pleased to give you the appropriate plan for a 7.5 cf vented cabinet.

I am talking with a guy named Chris from Solen.. I wonder if it's the same person. He sent me 3 designs.. 1 ported for the RSS and 1 ported and 1 sealed for the UM18...

He said that he can also make them or ship the 4 CF box that is available on parts express for $250 CAD..... not sure what to do...

 

[Verdinut]

The RSS460 would also work well in a properly tuned 9 cf cabinet.

 

[Verdinut]

I am talking with a guy named Chris from Solen.. I wonder if it's the same person. He sent me 3 designs.. 1 ported for the RSS and 1 ported and 1 sealed for the UM18...

He said that he can also make them or ship the 4 CF box that is available on parts express for $250 CAD..... not sure what to do...

Yep, it's the same person.

 

[Verdinut]

I am talking with a guy named Chris from Solen.. I wonder if it's the same person. He sent me 3 designs.. 1 ported for the RSS and 1 ported and 1 sealed for the UM18...

He said that he can also make them or ship the 4 CF box that is available on parts express for $250 CAD..... not sure what to do...

The sealed 4 cf has an F3 of 27 Hz. however, you could get a lower f3 at 22 Hz in vented 9 cf box with the RSS460. The decision is yours.

 

[moves]

The 4 cf has an F3 of 27 Hz. You could get a lower f3 at 22 Hz in vented 9 cf box with the RSS460. The decision is yours.

So the lower F value is what I should be looking for?

The following are the Fs values for the boxes Chris sent me:

UM18 vented f3 value of box = 18.87 @ 7 Cubic feet
UM18 sealed f3 value of box = 32.04 @ 3.715 cubic feet
RSS vented f3 value of box = 23.51@ 7 Cubic feet

If lower F is better then it looks like the vented box with the UM18 is the best choice no?

 

[Verdinut]

If you get the 4 cf box for the UM18-22 that's fine too. You would be able to EQ it with a DSP for a stronger low frequency response anyway.

 

[Verdinut]

So the lower F value is what I should be looking for?

The following are the Fs values for the boxes Chris sent me:

UM18 vented f3 value of box = 18.87 @ 7 Cubic feet
UM18 sealed f3 value of box = 32.04 @ 3.715 cubic feet
RSS vented f3 value of box = 23.51@ 7 Cubic feet

If lower F is better then it looks like the vented box with the UM18 is the best choice no?

If you're aiming for the lowest and flatter response, yes the UM18-22 in a 7 cf ported box would be the best choice. But for a good performance with an adequate tight bass, you will need an amp such as the QSC DCA 2422 which will cost you close to C$2000 to drive it.

 

[Verdinut]

The UM18 in the sealed 4 cf from Parts-Express will have an F3 at 27 Hz which can be EQ'd, or you could opt for the RSS460 in the vented box.