Sealed Enclosure Design Help

[giralfino]

What am I missing looking at the plot showing 100 db at 40 Hz with 25 W input, considering the claims that no "real bass" can be had from these drivers.

What you are missing IMHO is the fact that at 150Hz and up you'll have more than 112 db at the same conditions. So the claim is true: unless you move to a better suited enclosure the bass from this driver in the simulated sealed enclosure will sound thin or nearly not existent.

Ralf

 

[speaker dave]

We are really talking about 2 different things. One is the natural response in a sealed or vented box, the second is the maximum output available, perhaps with an equalized allignment. Usually these are called the small signal and large signal conditions.

Since the system was designed for high efficiency, the unequalized response won't go as low (without EQ) as a high mass low efficiency woofer. Yet, for the equalized case nothing matters but excursion related output capibilities.

David S.

 

[gberchin]

I read this thread and wonder what I am missing. I see a really good-sounding driver from the midbass on up, that happens to roll-off below 91 Hz. I also see that it can produce 100 dB @ 40 Hz, with a few dB of EQ boost, before excursion- or power-limiting. And I see a lot of people who are saying that it won't work.

Not all situations require 120 dB @ 16 Hz! I think that this configuration will be wonderful, within its limitations.

 

[mefistofelez]

Hi David and gberchin,

I think that you have identified the issues clouding the discussion, which probably stem from my unfortunate use of the term "real bass", which people probably associate with sub-woofers.

Thank you for confirming that the alignment will work for the intended design frequency range and SPL.

Kindest regards,

M

 

[Cal Weldon]

Hi Cal,
Is it a semantics issue?

Perhaps, and I have been known to take things to an extreme. I really don't need deep bass. 40 or 50Hz is fine for me. In my big system I use the A7 cabinets with a Selenium woofer for my 'satellites'. That woofer has more oomph than the 515, albeit at the compromise of the vocals, but many are happy with that as a stand alone speaker. I just like to take it up a notch and add that same woofer in the A4 cabinets to 'fill-in' the low end rather than add EQ and possibly overwork the woofer. To each his own M and no one here can tell you what sounds good to you. Either way, the 515 is a great driver, no bones about it.

Cheers.

 

[Cal Weldon]

the term "real bass", which people probably associate with sub-woofers.

That was my mistake. I hear many persons talking about their 16Hz when chances are they're not hearing the fundamental.

 

[tvrgeek]

I used to be with Cal on the need for really deep bass, but after adding subs to all my systems, I can't do without. I listen to a lot of jazz and classical. There is not a lot there, but it adds surprisingly a lot. I don't do honking 16 Hz jobs. More like -3 @ 30, after room gain. Maybe if I went back to floor standers that could do 40 I'd be OK.

Anyway, it looks like these drivers are woofers, not subs. Different design requirements. Build them as woofers and see how they sound to you. You are the only one they need to please. Might consider a C4 alignment rather than QB3 for the perception of a bit more bass. You may find that in a room with real music, they are just fine. Then if you need a sub, build some subs.

 

[mefistofelez]

Hi Cal, tvrgeek,

sorry for my sloppiness with language.

Just like tvrgeek I mainly listen to classical and vocals, so with the help of room gain and perhaps little equalization, I should have enough bass. Also, I will be crossing over at about 900Hz, so the beautiful mid-range will be appreciated.

I will re-evaluate after i finish Unities, which should go down to about 300Hz.

Kindest regards,

M