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Bobby

Need a little help in the bass region

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Hi guys,

Need advice on the bass system for my HT. Have six ultimax um-18 in ported cabs on the front in a array and think  about modifying them and put them in sealed boxes,for faster and thighter bass, better group delay and for easier integration,I think. Is a total external volume of about 7 cft sealed box( that is the easiest practical volume after modification)to big for the um18? I saw that on databass it was tested in a 6,16 cft external, and Dayton recommendations is an internal of 4,2 net volume. I have a few Magnum-12 drivers (diysoundgroup)from another project and want to integrate them in a system as midbass modules with the ultimax to split the frequency, the um-18 to about 50Hz and the magnums from 50 to 120Hz, from a single LFE output and split with a miniDsp. The room is about 23’,16’,7,5’ all concrete walls,floor and ceiling; on the back wall is an porous absorber 2’ thick,floor to ceiling,wall to wall.

I ask you if going from ported to sealed is a good ideea? forgot to say that from the six ported boxes,two of them that I put in the center of the grid are smaller And after measurements with rew they look a little bit different that the bigger left and right arrays .If I don’t go sealed,I don’t have the space for the Magnums and the two way bass system.Do you think this will work?

 

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You might wanna ask this question on AVS again, but unless your cab is severely mistuned, the issues you‘re hearing are likely room issues.

I have no experience with the um-18, but apparently it‘s also pretty capable in the mid-bass region. I‘m not sure if dropping those drivers in sealed cabs would yield your desired improvements.

I have seen other people using (multiple) um-18s seeking for better misbass performance, which makes me wonder why not go for the 21ds115 or similar instead. I know in the states they‘re similarly priced and you‘ll lose a bit of deep bass (displacement), but you‘ll gain a lot of sensitivity.

If those magnum drivers are high sensitivity drivers, I‘d give them a shot. Should work rather nicely in sealed cabs.

What other subs are you using in your setup, for which you‘re hoping for better integration?

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Could be room issues. Its pretty easy to stuff your ports and get a sense of what a sealed box sounds like. The larger box volume won't negatively affect the midbass at all. Only really increases efficiency down low. Just make sure to turn off your high pass filter once you seal it... and go easy at first!

But what you really might just need it to figure out if you have some standing waves in that room that negatively affect the bass. Just move the subs and see what happens. I would also consider getting a higher efficiency 18" driver and just switching that. But before doing anything costly, what sort of power are you running to your subwoofers?

 

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22 hours ago, peniku8 said:

You might wanna ask this question on AVS again, but unless your cab is severely mistuned, the issues you‘re hearing are likely room issues.

I have no experience with the um-18, but apparently it‘s also pretty capable in the mid-bass region. I‘m not sure if dropping those drivers in sealed cabs would yield your desired improvements.

I have seen other people using (multiple) um-18s seeking for better misbass performance, which makes me wonder why not go for the 21ds115 or similar instead. I know in the states they‘re similarly priced and you‘ll lose a bit of deep bass (displacement), but you‘ll gain a lot of sensitivity.

If those magnum drivers are high sensitivity drivers, I‘d give them a shot. Should work rather nicely in sealed cabs.

What other subs are you using in your setup, for which you‘re hoping for better integration?

I can’t switch the drivers no more, I will stay with the um’s and the Magnums, that are pretty sensitive drivers and give it a shot; I hope to integrate them with the Um’s and split the frequency range in two, say 5-50Hz to the Um’s and 50-120Hz to the Magnums.

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25 minutes ago, Bobby said:

I can’t switch the drivers no more, I will stay with the um’s and the Magnums, that are pretty sensitive drivers and give it a shot; I hope to integrate them with the Um’s and split the frequency range in two, say 5-50Hz to the Um’s and 50-120Hz to the Magnums.

Ported subs are easy to integrate if they are the lowest playing speakers in the system. If you have ported subs and want to run something below that (like sealed or other deeper ported subs), you'll have a hard time on doing so. FIR filtering might be the only solution, at the cost of delay and ringing. But since that's not the case you won't have to worry about that.

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10 hours ago, Kyle said:

Could be room issues. Its pretty easy to stuff your ports and get a sense of what a sealed box sounds like. The larger box volume won't negative affect the midbass at all. Only really increases efficiency down low. Just make sure to turn off your high pass filter once you seal it... and go easy at first!

But what you really might just need it to figure out if you have some standing waves in that room that negatively affect the bass. Just move the subs and see what happens. I would also consider getting a higher efficiency 18" driver and just switching that. But before doing anything costly, what sort of power are you running to your subwoofers?

 

Have three inukes6000 dsp, one channel for each driver.I will take some more measurements with rew to see what happened.It can still be a room issue to, but since I installed the huge absorber on the back wall the standing waves are diminished pretty much.I always felt that the ported boxes sound boomy sometimes in my room; is a sealed cab gone to sound different in room then the ported box? for budget reasons,can’t sell the um-18 and go with another driver, just modify the ported and make smaller sealed boxes to have space to accommodate the Magnums-12 to take care for the midbass.Do you think that approximately 7 cft exterior volume is ok fot the Ultimax in sealed enclosure?

 

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10 minutes ago, peniku8 said:

Ported subs are easy to integrate if they are the lowest playing speakers in the system. If you have ported subs and want to run something below that (like sealed or other deeper ported subs), you'll have a hard time on doing so. FIR filtering might be the only solution, at the cost of delay and ringing. But since that's not the case you won't have to worry about that.

Thank you!

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Are you using some kind of EQ (manual or auto) right now? 

Do you have any idea how much output you need vs. what you have in the deep bass?  Switching to sealed will give up a lot of it, and you might want to use some EQ to bring response up, at the cost of more headroom.

The other issue will be the integration complexity, especially if the Magnums-12s are ported, as noted in earlier posts.  Will all the different subs be placed close to one another?  That definitely makes it easier.  Will sealed vs. vented Magnum 12s give you enough output?  If so, this will give you the most flexibility with respect to crossover.

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Have some miniDsp for EQ; my goal is to achieve about 130db at 20 and 120db at 10hz in room.Do you think it’s possible with 6 sealed Ultimax and 4 sealed Magnums? What do you think is the ideal enclosure volume for the ultimax?(I’m not familiar with winISD yet)
Want to put the Magnums right beside the Ultimax when sealed.Here is a pic with the actual setup.

4140DA63-7A7F-4CA6-ACC9-E5F3B642AE6E.jpeg

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