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New Bascabinet RR 105.4 (B200G sp1076)

 
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willem-57
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Joined: 18 Jul 2014
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Location: Netherlands

PostPosted: Sun Jan 04, 2015 11:04 pm    Post subject: New Bascabinet RR 105.4 (B200G sp1076) Reply with quote

I wanna make a new and better bascabinet for my 105.4 speakers. It would be ideal if i had a datasheet of the B200G sp 1076 witch is only used in the RR105.4.
I do have a datasheet of the B200G sp 1075 witch was mutch used in several models but has another resistance.
My question: are most the data of both speakers the same? And in particulair the liters for an enclosed box (20-25 liters for the sp 1075)


Last edited by willem-57 on Tue Jan 06, 2015 8:46 am; edited 2 times in total
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SaSi
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PostPosted: Mon Jan 05, 2015 8:26 pm    Post subject: Reply with quote

I doubt that any change in the enclosure volume would have a significant effect on the sound, if you stick with sealed. Venting them would aim for a different design and you would need to have the specs before being able to model.

What are your plans on the bass cabinet?
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willem-57
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PostPosted: Tue Jan 06, 2015 8:26 am    Post subject: Reply with quote

At first, a good 2015 SaSi, and also for the other people here.

My plans are to make a more slim and higher bascabinet of 18 mm MDF, with round edges, like the head, so it will look more modern and same shaped as the head.
Measurements of the bascabinet will be about 74 cm high x 30 cm deep x 24 cm wide. I will make 2 braces in it, also at some bitume on the panels and off course damping material. I'm thinking to make the internal a bit bigger, 45 liters instead of 40 they are now, will that increase the bass notes, or do i get disortion or a flubby bas?
Original the 105.4 is about 96 cm high, this will be with the new cabinet about 110 cm, so the sound will also improve because the stage will be on a proper ear height when you sit on a chair.

Datasheet of the almost simulair B200G sp1075. By the way, is there somewhere a datasheet of the sp1076?

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SaSi
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PostPosted: Tue Jan 06, 2015 10:45 am    Post subject: Reply with quote

Hello, and a happy and prosperous 2015 to you and everyone here.

I doubt you will be able to find a datasheet for the SP1076, mainly because it was never in the DIY/KIT market. All the drivers with datasheets were made available in "constructor series" or kit forms.

Thinking about what you want to achieve with the new enclosure, I recommend you think about building a 4th order bandpass enclosure, something with the external dimensions of the R107.

I've done this with for use with a pair of heads from an R107 system that was scrapped (!!) and I can say I am impressed with the results. Bass extension and tightness is way much better than the R105, which is a larger cabinet than the R105.4 and goes down about an octave lower than the .4

I have kept the external dimensions identical to the R107, used 20mm plywood (I should have used 16mm and used 2 more layers of bitumen) and made internal rear compartments of about 20lt each with a front shared chamber of about 13lt. The vent is 29x12x41mm.

Everything inside was covered with 2 layers of 3mm bitumen sheet (roofing felt - I'm told it is) glued with contact cement.

I am using the original R107 low section crossovers - which contains conjugate sections to make impedance an constant 4Ohms.

I tried several different drivers - all KEF - including the SP1075, SP1070, SP1069, SP1022, SP1039 and SP1014. The results were similar with 8ohm drivers and not very good with the 5Ohm SP1075 drivers. Marginally best were the SP1014 ones.

You may have an issue to address with the heads being 8Ohms instead of the 4Ohms the R107 drivers are but I'm sure the original R105.4 crossover takes care of that.

I know it's a long shot but if it turns out right, you will be impressed with the performance and never look back.
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willem-57
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PostPosted: Tue Jan 06, 2015 2:25 pm    Post subject: Reply with quote

My intention is to keep the speaker as it is, because the filter etc is build for the used design. Also i like the bass from a closed box. But i will make it more modern and use better materials. The sound of the 105.4 is very good. About 15 years ago i owned a 107, but the bas was way too mutch in my modest room.
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willem-57
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PostPosted: Sat Jan 10, 2015 6:27 pm    Post subject: Reply with quote

Another question, is the B200 bass unit (SP1070), whitch is sitting in the model 303 the same dimension as the B200G sp 1075? Wanna know this so i can use it as a model for making the cutting out edges of the new bas cabinet. Someone can do this for me, so i have to send him a speaker, but i don't want to send the Original ones, suppose it got lost. So i want to buy a set of 303's witch are very cheap and i also have than a set of spare tweeters T33sp1074.

Can i use the B200 bass SP1070 as a model for the B200G SP1075 Question

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SaSi
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PostPosted: Sun Jan 11, 2015 10:31 am    Post subject: Reply with quote

Yes, minor differences from model to model - check the depth clearance. If you have them both, you can rest an SP1070 on it's face on the SP1076 (correct?) and confirm.

So far, I've seen all "delta" drivers having the same baffle profile.
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willem-57
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PostPosted: Sun Jan 11, 2015 11:08 am    Post subject: Reply with quote

Thx, i will do so. The 303's i bought for 35 euro/pair. So, no problem as an speaker will be lost. By the way they are playing now and must say nice speaker, great sound for such a small and simple box. Very Happy
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speakerguru
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PostPosted: Sun Jan 11, 2015 11:44 am    Post subject: Reply with quote

willem-57 wrote:
Can i use the B200 bass SP1070 as a model for the B200G SP1075 Question
Yes, the chassis is the same.
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willem-57
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PostPosted: Fri Feb 20, 2015 10:18 pm    Post subject: Reply with quote

Thx for the reply, i have drawings for the new Bascabinet, see the topic of the 105.4: http://www.hifiloudspeakers.info/speakertalk/viewtopic.php?t=1585&postdays=0&postorder=asc&start=75
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