Enclosure Design for Eighteen Sound 18LW1400

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cph2000

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Joined 2004
I would definitely go with a sealed enclosure for home use, and possibly with a low Q between 0.5-0.65. Chances are that you will have to stack these in a corner or against the front wall, and in that case the response you will get in your room is very different from what you will simulate. If you place the woofers in the corners of your room the direct sound will be in line with the first order reflections (see the lyngdorf boundary woofers) and with a bit of dsp and time delay for your main speakers you can get impulse aligned sound in the room at your listening position. I have heard this done and was amazed at how tight and coherent the bass was. The easy route is to get a lyndorf amp and a cheap pa amp for your subs.

Here is an example of a guy that has used your woofers in a home system (sorry in danish)
Reference hojttalere i reference rum - SpeakerBuilder Forum - Page 12
 
freddi

freddi

Member
Joined 2005
I used to use 4-vented 18 boxes - 2 -177l and 2-222l for a home system - I vented them like the R-J using a subbaffle spaced with 2"x2" cleats. Here's the 177l box - the 222l box below looked the same only taller. Response could be measured with mic in the aperture.

l7OjCYg.jpg
 
academia50

academia50

Member
Joined 2013
cph2000 said:
Here is an example of a guy that has used your woofers in a home system (sorry in danish)
Reference hojttalere i reference rum - SpeakerBuilder Forum - Page 12
Click to expand...



Hi cph2000, thanks for the link.;)

Indeed, it is in Danish, and I should register to see the photos.
Anyway I have read a little and I BELIEVE that the driver18 Sound that I chose is an excellent choice even for a home use.

To achieve that, I am evaluating some more power and correction by DSP, buy Mini DSp instead of Dayton SPA250 , of course they are other values, but I think it would gain a lot in performance ...

PWR-ICE250 | DSP plate amplifier powered by IcePower technology

Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

In addition, this model MiniDSP can be used both in stereo and monophonic configuration, which would allow me to start with a single cabinet and then move to two drivers Eigtheen Sound if necessary.......

So, do you need two subwofers? according to this link, wall yes ..

Stereo Subwoofers: Why Every Man Needs Two


Ohhh, this is getting too complicated ..... with MiniDsp I would not have high level input (connection by loudspeakers) and I wanted to use my Prima Luna valve amplifier and use the NAD 3020 for other uses .....:mad:
 
academia50

academia50

Member
Joined 2013
cph2000 said:
A good explanation of the boundary woofer system can be seen here:
YouTube
And
YouTube

Fast woofers with large BxL and low mms are generally preferred to have optional time domain response, the frequency response can be fixed using dsp. Your woofers are good in this sense.

YouTube
Click to expand...

I do not understand spoken English, I'm sorry. :eek: Thanks equally for the links.:)

The paragraph in bold is what I wanted to read ! :)
 
academia50

academia50

Member
Joined 2013
Well, I think the decision is made, I will build a single cabinet with a speaker according to the plans of the manufacturer and I will correct with the software of MiniDsp until finding the best balance with the satellite cabinets.
:confused: But, I am somewhat confused with modern technologies. Can anyone tell me if it is possible to use the MiniDSP connected to my valve amplifier by means of the speaker output?

Can I connect the balanced XLR Analog 1 and 2 XLR connections directly to the unbalanced outputs of the valvular amplifier output transformers?

Is there any risk ? :eek:

To be clearer, can I use the MinDspi connecting just as the Dayton SPA250 would do using the high-level connection ?

I attached the information, thanks in advance, friends, and, sorry my english..
;)

PWR-ICE250 | DSP plate amplifier powered by IcePower technology


miniDSP PWR-ICE250 2 x 250 Watt DSP ICEpower Plate Amplifier

https://www.parts-express.com/pedoc...50-watt-dsp-icepower-plate-amp-data-sheet.pdf
 

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academia50

academia50

Member
Joined 2013
GM

Thanks for the link. ;) It has helped me to realize that I have confused the XLR (balanced, line) connector with the Speakon professional speaker connector (high level)

Definitely, MiniDSP PWICE250 can not take the signal from the output stage of an amplifier. Be of solid state or with valves.:mad:


Hmm, it seems that I have no alternative to go for Dayton SPA250, but it has no DSP correction ..... why do they all so complicated ? :rolleyes:

Maybe there is some way. to connect the speaker output of the valve amplifier to the low level input of MiniDsp (RCA connectors) ...... I will have to continue investigating, I will appreciate any suggestion with the corresponding scheme....
 
academia50

academia50

Member
Joined 2013
I think I remember that you achieve 18 Hz with analog technology., I wish I could achieve that ....... .wow !!! :eek:

The information I was looking for is here,

Connecting an Amplifier to a Receiver Without Pre-Outs - Page 3 - Blu-ray Forum


, but there are some doubts on my part, which may be unfounded, the internet is an inexhaustible source of knowledge ... and confusion, being able to separate the straw from the wheat, is difficult.



I can continue to use Nad 3020 which has pre-out output towards the Mini DSP and towards the Prima Luna as I have done and is working acceptably with my vintage JBL...:)

Then, obviously, it will do much better with a modern 18-inch speaker, a good box, more wats, and electronic correction.


But ..... I read that one of the most renowned subwoofers, Rel, recommends using the high level connection for its minimum phase deviation because it is more direct .....

REL Acoustics | Powered Subwoofers for Home Theater Systems

Well, what does my phase deviation matter if I can correct it with MiniDsp?

I think, to be honest, I have some fear of embarking on the necessary adjustment through the soft provided by MiniDsp...:eek:

Is that I wonder if it will be worth ..... I want to enjoy the music, not learn to use sophisticated software ....:D
 
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academia50

academia50

Member
Joined 2013
:confused:;):)

Ohhhh, different languages sometimes cause misunderstandings ...... I do not understand that phrase, but you can rest assured that mine is very serious. What happens is that I no longer have the neurons so agile.

The diagram is excellent, thank you very much !!!

The buffer would be a series resistor to balance impedances, am I correct? An approximate value would be 47 Kohmn ?
 
B

BesPav

Member
Joined 2011
academia50 said:
The buffer would be a series resistor to balance impedances, am I correct?
Click to expand...


No, buffer is a some kind of follower with unity gain, it must have high input resistance (in range of megaOhms) and low output impedance (in range of Ohms/milliOhms).
High input impedance will keep divider from any loading and low output impedance will keep you from hearing wires/connectors/etc.

Balancing impedances for single-ended source needed with balanced receiving for keeping good CMRR.
 
academia50

academia50

Member
Joined 2013
Thanks bespav, here I found a good article on impedance matching. It is as you say.

Tackling One of the Most Confusing Subjects in Audio Electronics


But WAF has rebelled these days and I do not know if I can embark on making a new cabinet. Problems of size, of course, is always the same in marriage...:D

So I had an idea, but I do not know if it's good. You know Troels DTQWTII, what do you think of connecting MiniDsp only to the bass section? 2 x Eminence DeltaLiteII will be able to descend to 20 hertz without having mechanical damages? . :confused:
Remember that I do not have SET, but push pull valves Prima Luna. Then I would not really need the specific network to reinforce the bass zone as it was created by Troels for 300B or similar. I could undo this divider easily because I have provided double connection binding post terminal in my construction, and connect the PWRICE250 ....
I leave the Deltalite 2510II links to see TS (xmax seems small for use as subwoofer ....)



PWR-ICE250 | DSP plate amplifier powered by IcePower technology


http://www.eminence.com/pdf/DeltaliteII_2510.pdf

Wow, if I connect in parallel I'll have 2x250W @ 4Ω !!! ;)

I would like opinions all about this , sorry for the off topic....:)
 
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