Ported Cabs vs Sealed

[Bass Culture]

I understand very little of the technical content of this thread but - perversely - am finding it completely fascinating all the same!

[jb90]

Hi could you help me? Could you tell me what kind of cab it is? Ported or sealed? The speakers are Eminence Beta12A. How can I measure frequency response of that kind of speakers in that cabinet size? It's good for 5 string bass, enough low end? Thanks.  

 

[Bill Fitzmaurice]

That's ported. Measuring frequency response is done with software, like HolmImpulse, and a USB measurement mic. The Beta 12 is an entry level driver, so whether it's adequate for your needs only you can say.

[jb90]

12 minutes ago, Bill Fitzmaurice said:

That's ported. Measuring frequency response is done with software, like HolmImpulse, and a USB measurement mic. The Beta 12 is an entry level driver, so whether it's adequate for your needs only you can say.

Entry level? So not pro sounding? So maybe I should looking for sth else? I used this calculator https://www.lautsprechershop.de/tools/t_box_vented_hoges_en.htm and it says that ported cab with that speakers should have +/- 3db on 40hz and sealed one +/- 3db on 85hz  so if it's ported then it would be great but I don't know if this particular size of the cab gives that freq response. And I don't know how to check that without any measuring tools. I don't have that but I just wanted to know if there will be great sound and good low end from this cab. I play on 4 string but I will buy 5 string soon and want to have good sound from those low notes too.

Edited March 5, 2022 by jb90

[Bill Fitzmaurice]

For -3dB at 40Hz would require an internal box volume of 300 liters, exclusive of the space taken up by the port and the drivers. You don't necessarily have to go that low, a 50Hz F3 from a net box volume of 200 liters would suffice. But with less than 200 liters the low end would fall off rapidly. There's also the matter of the 4.4mm driver xmax. That's adequate for the most part with a low E, but not with a low B.

[Phil Starr]

Can you clarify the speakers in the video aren't the Beta 12A's but the BP122's which are at least designed specifically for bass. Are you retrofitting the Beta's?

 

These are entry level speakers but I'm a little more optimistic about them, they are the sort of drivers fitted in a lot of mid priced gear, nothing special but not awful either and they have a very enhanced top end so will give you a lively sound a lot of people like. The cab looks to be around 100l which is very much on the small side to get the best low end out of them but that does improve power handling. Even so a high pass filter would help a lot. You are going to get a bit of a rise in the 100Hz region which will give them a bit of a thump and smiley faced eq built in. Again this is common in a lot of mid-range gear. I think personally there is a lot of nonsense about the 'is it good for low B' question. Most of the fundamental is filtered out simply because of the positioning of the pickups right down the bottom end of the strings which means if the speaker isn't overloaded across the frequency range it shouldn't be overwhelmed at low B, not to mention that not many songs have you play a continuous low B or even anything below E. Unless you are going to use a 500W amp absolutely cranked with lot's of bass boost I think you'll find it will be OK. The cab is going to have a strong sound of it's own though so give it a good listen before buying.

 

Lot's of love for Poland over here at the moment btw. 

 

Eminence Cab designs

[Bill Fitzmaurice]

47 minutes ago, Phil Starr said:

Can you clarify the speakers in the video aren't the Beta 12A's but the BP122's which are at least designed specifically for bass. Are you retrofitting the Beta's?

Neither of those are 200 watt, so I suspect those in the video are B102 or BP102. The magnet in the video also looks too large for the frame to be a twelve. It's true that one doesn't need a 32Hz F3 for low B, no more than does anyone need a 41Hz F3 for low E. But low B is still more demanding than low E, so I'd want at least 6mm xmax for low B use. 6mm xmax is usually going to cost more, but my philosophy is buy once, cry once.

[jb90]

4 hours ago, Bill Fitzmaurice said:

For -3dB at 40Hz would require an internal box volume of 300 liters, exclusive of the space taken up by the port and the drivers. You don't necessarily have to go that low, a 50Hz F3 from a net box volume of 200 liters would suffice. But with less than 200 liters the low end would fall off rapidly. There's also the matter of the 4.4mm driver xmax. That's adequate for the most part with a low E, but not with a low B.

I find out from HandBox site that this cab have 50-16k freq response. I don't know how much +/- db's here or there but that's what info on the site says. Could you tell me about xmax value? What does it mean for bass speaker?

[jb90]

2 hours ago, Phil Starr said:

Can you clarify the speakers in the video aren't the Beta 12A's but the BP122's which are at least designed specifically for bass. Are you retrofitting the Beta's?

 

These are entry level speakers but I'm a little more optimistic about them, they are the sort of drivers fitted in a lot of mid priced gear, nothing special but not awful either and they have a very enhanced top end so will give you a lively sound a lot of people like. The cab looks to be around 100l which is very much on the small side to get the best low end out of them but that does improve power handling. Even so a high pass filter would help a lot. You are going to get a bit of a rise in the 100Hz region which will give them a bit of a thump and smiley faced eq built in. Again this is common in a lot of mid-range gear. I think personally there is a lot of nonsense about the 'is it good for low B' question. Most of the fundamental is filtered out simply because of the positioning of the pickups right down the bottom end of the strings which means if the speaker isn't overloaded across the frequency range it shouldn't be overwhelmed at low B, not to mention that not many songs have you play a continuous low B or even anything below E. Unless you are going to use a 500W amp absolutely cranked with lot's of bass boost I think you'll find it will be OK. The cab is going to have a strong sound of it's own though so give it a good listen before buying.

 

Lot's of love for Poland over here at the moment btw. 

 

Eminence Cab designs

I don't know about this particular video but I know that Eminence Beta12A are speakers in this cab. I compare them with other Eminence speakers and their round part of the speakers looks like Beta speakers. 
Why I should use HPF on this cab? 
I have 400w hybrid amp. I can't hear it unfortunately. I ask those questions because I read on facebook group that those speakers and this cab can be somewhat weak chain in my signal path because of those speakers freq response and size of the cab. And I don't wanna get cab which is not good for bass. Of course I don't need subbass on the scene or during rehearsals because it's just a mud and nothing else but I want to have all usable low end in my gear and if this cab don't meet my expectations with it then maybe I should looking for something else? But which one? People say that specs don't play but definitely you can't cheat physics and acoustics so those parameters can tell a lot about gear. I have had AMpeg 410HLF and I know that I don't wanna have so much subs, scooped mids, and so harsh treble like 410HLF has. And I need smaller cab for sure. I had GK NEO 2x12 and that was nice cab but probably a little bit too much modern to my taste? Since then I knew that 2x12 will be a sweetspot between great sound and reasonable wight and size. I had 15' Ampeg and Taurus amps and 15' is probably not what I like. Kind of muddy sound. Nice lows, harsh treble and mids. Lot of muddy mids.

[jb90]

1 hour ago, Bill Fitzmaurice said:

Neither of those are 200 watt, so I suspect those in the video are B102 or BP102. The magnet in the video also looks too large for the frame to be a twelve. It's true that one doesn't need a 32Hz F3 for low B, no more than does anyone need a 41Hz F3 for low E. But low B is still more demanding than low E, so I'd want at least 6mm xmax for low B use. 6mm xmax is usually going to cost more, but my philosophy is buy once, cry once.

I compared Beta12A speakers with those B102 and BP102 and the speakers looks like Beta's. This black outer part of the speaker looks like on Beta's not like in B or BP speakers. I know that probably -3db for 55-60hz for 5 string and -3db for 75-80hz will be enough (or even -6db I guess) but I still don't know if this cab can handle it. Or at least can handle without lost important low end frequencies which will be necessary to get good low end from my basses. If Beta's will be bad choice I will definitely buy other similar speakers with better specs but which one will be better? What should I looking for? I need to know answers for those questions to be sure I know what should I looking for. Thanks.   

[Bill Fitzmaurice]

Xmax is the distance the cone can travel before distortion becomes severe. The longer the xmax the louder it can play. The best way to compare different drivers is with speaker modeling software. The program I use the most for sealed and ported cabs is WinISD 0.7. With it you can see the effects of the box size and tuning, and see Maximum SPL, which is determined by both the voice coil power limit and xmax.

[Downunderwonder]

The faster the speaker cone moves the further it must travel to maintain the frequency relationship. Both of those take more power to do. Low bass eats power.

[Dad3353]

4 hours ago, Downunderwonder said:

The faster the speaker cone moves the further it must travel to maintain the frequency relationship. Both of those take more power to do. Low bass eats power.

 

The speed of cone movement is the frequency, no..? 

[Waddycall]

Maybe it depends on the combination of frequency and amplitude?

[Bill Fitzmaurice]

2 hours ago, Dad3353 said:

 

The speed of cone movement is the frequency, no..? 

No. Let's say the frequency is 100Hz. That means the cone must go from rest to full outward excursion to full inward excursion and back to rest 100 times per second. If it does so over a distance of, say, 6mm it must move six times faster than it does over a distance of 1mm. How cone velocity can affect the result is explained here: http://www.readresearch.co.uk/loudspeaker_papers/klipsch_modulation_distortion_article_1.pdf

[Downunderwonder]

7 hours ago, Dad3353 said:

 

The speed of cone movement is the frequency, no..? 

No. Speed is velocity, a unit of distance / time.

 

Frequency is how often something happens, unit kinda abstract but always /time

 

Independent of what is being described, the kicker is the wavelength, over which distance it takes an observer to experience the wave repeat.

 

Velocity = frequency x wavelength 

 

Turning up the loud knob makes the cone fly further making it louder, doesn't change the frequency. To travel further in the same time it must be travelling faster.

[BassmanPaul]

On 05/03/2022 at 15:09, Phil Starr said:

Lot's of love for Poland over here at the moment btw. 

 

And in Canada too!  From the bottom of my heart thank you for caring for the Children and their Mums!!