jaudere
Well-Known Member
Hi friends,
I have some questions. Before asking the questions, let me explain the back ground.
I have a new plan about open baffles.
I had a very good experience about Philips Hi-Q full range driver on open baffle. I had some space crunch. So I had dismantled my open baffles and I was using small bookshelve (Philips ready made with 4 full range drivers). I am/was happy with them.
The reason to say was is that, recently out of some fit, I took out the remaining pieces of open baffle and mounted 8 full rangers on them. I understood that those bookshelves are good for bedroom system and that I cant settle for anything other than open baffle. So I decided to build open baffles again.
I dont know the TS parameters of these Philips drivers. However I was quite satisfied with their performance on OB. This time I am planning to build flat OB rather than folded one (to avoid the problems of reflected waves). I will keep the width as 2 feet and height at 3.5 feet.
According to the baffle size calculator, for 24 there will be a roll off below 200Hz approx. (the calculator is 4560/baffle width in inches). So the bass output below this limit is very poor.
In open baffle systems, these problems are tackled in 3 ways.
1) active equalization: like orions
2) choose drivers such that the sensitivity of woofer is at least 6 dB more than mids/high(or full ranger in my case)
3) Choose woofer with QTS > 1(as I learnt recently, this high QTS is important only for low frequencies.i.e. woofers.)
After some search I found Eminence alpha 15 A to be a good choice but few people have mentioned that it can become boomy in smallish rooms. Besides it is a 15 speaker and I wont ask my friend to get it from US. With 2 naughty kids at home, I am not going to use a costly woofer.
Another option was Goldwood 10 or 12 woofer with QTS 1.1. However, the sensitivity is 86dB/W/m. It is extremely difficult to find a mids or full ranger with sensitivity 80dB( 6 dB less than Gldwood). Besides that I dont know how Goldwood would gel with full rangers. So I gave up on that.
When I do near field listening with Philips full rangers, I feel that their bass output is good. So I decided that I will use full ranger as woofer
So there are 2 plans about driver combinations to solve the difficulty with lower frequencies: In both the plans, no driver will actually work as full range; The lower driver will produce frequencies from 55-250Hz, the middle full ranger will produce frequencies from 55 to 4500 and tweeters above 4500. I feel that this should solve the situation where full rangers struggle to produce full frequency spectrum. They should theoretically perform better when given a task to produce wide range frequencies rather than full range.
1) 8 ohm Full ranger as woofer (with a low pass filter at 250Hz) + 8ohm full ranger as mid crossed with tweeter at 4.5 KhZ . In this design, frequencies below 250Hz will be played by 2 speakers which are identical(meaning perfect sonic match) and frequencies above 250 Hz be played by single speaker(250-4500 by full ranger and 4500+ by tweeter)
.
2) The second option which I thought about was that instead of using one 8 ohm single fullranger as woofer, I can use 2 full rangers of 4 ohms in series with the low pass filter at 250Hz. In this way I feel that I can achieve higher SPL below 250Hz without putting extra strain on my amp.
There are 2 plans about baffle design as well.
1) Complete flat baffle
2) Folded baffle for woofers so that I can add another foot of width to the baffle with 2 wings of 6 each. The middle speaker and tweeter will remain on flat baffle.
The Philips Hi Q full rangers are available in 4 as well as 8 ohms. This way I wont need active equalization . I am also more comfortable with smaller speakers. All speakers producing frequencies upto 4500 will be identical(all Philips 8 full rangers). So I hope there wont be much sonic mismatch (there may be some mismatch depending on quality of XO)
The total driver cost will be Rs 1800( 6 drivers at Rs. 300 each). I already have tweeters.
The low pass and 2 way filters are to be bought from parts express. The XO will be of Dayton and low pass filter, brand is unknown. Alternatively, I can buy the XO and low pass filter from Indian brand Ahuja. I am quite curious about Ahuja components. They will cost me Rs 3000 in total(costlier than Dayton, dont know whether it converts into a better quality or no.)I cant build XO myself. So I have to settle for readymade XO.
I had given a good thought to idea of active XO and gave it up after a bit of a search.
Till now I was not using tweeter. Cranky had explained me the purpose of using a tweeter(which actually I did not understand well). But I will take his word this time and cross full range at 4.5 K. This way, the majority of the used spectrum will still be produced by full ranger but it wont have to strain for higher frequencies.
Now here are my questions.
1) Which of the following give higher SPL at same wattage?
i) Single driver of 8 ohm
ii) 2 drivers of 4 ohm each, connected in series.
3) In all readymade cross overs, they have mentioned wattage. E.g. low pass filter of 250Hz , 650W RMS. What does that mean? What will happen if I use this filter with a 50 watt speaker or 300 W speakers?
4) I thank you for patiently going through my loud thinking, but do you feel
that this idea is feasible?
5) Does anyone have idea /experience about Ahuja components?
6) Can 2 woofers of 8 each give SPL equivalent to one 15 woofer at same
wattage and sensitivity?
7) Please have a look at the following link. It says that it is a one way XO but looking at the picture (by clicking on the larger view option), I felt that it is a 2 way XO with cut off at 4 KHz. If it looks confusing; I will go with the Dayton crossover.
Ahuja Sound Solutions
8) For low pass filter, I will have to use Ahuja only because parts express/madisound do not have low pass filter at 250 Hz (this is very important as this freq is decided by my baffle size.)
Ahuja Sound Solutions
Regards
I have some questions. Before asking the questions, let me explain the back ground.
I have a new plan about open baffles.
I had a very good experience about Philips Hi-Q full range driver on open baffle. I had some space crunch. So I had dismantled my open baffles and I was using small bookshelve (Philips ready made with 4 full range drivers). I am/was happy with them.
The reason to say was is that, recently out of some fit, I took out the remaining pieces of open baffle and mounted 8 full rangers on them. I understood that those bookshelves are good for bedroom system and that I cant settle for anything other than open baffle. So I decided to build open baffles again.
I dont know the TS parameters of these Philips drivers. However I was quite satisfied with their performance on OB. This time I am planning to build flat OB rather than folded one (to avoid the problems of reflected waves). I will keep the width as 2 feet and height at 3.5 feet.
According to the baffle size calculator, for 24 there will be a roll off below 200Hz approx. (the calculator is 4560/baffle width in inches). So the bass output below this limit is very poor.
In open baffle systems, these problems are tackled in 3 ways.
1) active equalization: like orions
2) choose drivers such that the sensitivity of woofer is at least 6 dB more than mids/high(or full ranger in my case)
3) Choose woofer with QTS > 1(as I learnt recently, this high QTS is important only for low frequencies.i.e. woofers.)
After some search I found Eminence alpha 15 A to be a good choice but few people have mentioned that it can become boomy in smallish rooms. Besides it is a 15 speaker and I wont ask my friend to get it from US. With 2 naughty kids at home, I am not going to use a costly woofer.
Another option was Goldwood 10 or 12 woofer with QTS 1.1. However, the sensitivity is 86dB/W/m. It is extremely difficult to find a mids or full ranger with sensitivity 80dB( 6 dB less than Gldwood). Besides that I dont know how Goldwood would gel with full rangers. So I gave up on that.
When I do near field listening with Philips full rangers, I feel that their bass output is good. So I decided that I will use full ranger as woofer
So there are 2 plans about driver combinations to solve the difficulty with lower frequencies: In both the plans, no driver will actually work as full range; The lower driver will produce frequencies from 55-250Hz, the middle full ranger will produce frequencies from 55 to 4500 and tweeters above 4500. I feel that this should solve the situation where full rangers struggle to produce full frequency spectrum. They should theoretically perform better when given a task to produce wide range frequencies rather than full range.
1) 8 ohm Full ranger as woofer (with a low pass filter at 250Hz) + 8ohm full ranger as mid crossed with tweeter at 4.5 KhZ . In this design, frequencies below 250Hz will be played by 2 speakers which are identical(meaning perfect sonic match) and frequencies above 250 Hz be played by single speaker(250-4500 by full ranger and 4500+ by tweeter)
.
2) The second option which I thought about was that instead of using one 8 ohm single fullranger as woofer, I can use 2 full rangers of 4 ohms in series with the low pass filter at 250Hz. In this way I feel that I can achieve higher SPL below 250Hz without putting extra strain on my amp.
There are 2 plans about baffle design as well.
1) Complete flat baffle
2) Folded baffle for woofers so that I can add another foot of width to the baffle with 2 wings of 6 each. The middle speaker and tweeter will remain on flat baffle.
The Philips Hi Q full rangers are available in 4 as well as 8 ohms. This way I wont need active equalization . I am also more comfortable with smaller speakers. All speakers producing frequencies upto 4500 will be identical(all Philips 8 full rangers). So I hope there wont be much sonic mismatch (there may be some mismatch depending on quality of XO)
The total driver cost will be Rs 1800( 6 drivers at Rs. 300 each). I already have tweeters.
The low pass and 2 way filters are to be bought from parts express. The XO will be of Dayton and low pass filter, brand is unknown. Alternatively, I can buy the XO and low pass filter from Indian brand Ahuja. I am quite curious about Ahuja components. They will cost me Rs 3000 in total(costlier than Dayton, dont know whether it converts into a better quality or no.)I cant build XO myself. So I have to settle for readymade XO.
I had given a good thought to idea of active XO and gave it up after a bit of a search.
Till now I was not using tweeter. Cranky had explained me the purpose of using a tweeter(which actually I did not understand well). But I will take his word this time and cross full range at 4.5 K. This way, the majority of the used spectrum will still be produced by full ranger but it wont have to strain for higher frequencies.
Now here are my questions.
1) Which of the following give higher SPL at same wattage?
i) Single driver of 8 ohm
ii) 2 drivers of 4 ohm each, connected in series.
3) In all readymade cross overs, they have mentioned wattage. E.g. low pass filter of 250Hz , 650W RMS. What does that mean? What will happen if I use this filter with a 50 watt speaker or 300 W speakers?
4) I thank you for patiently going through my loud thinking, but do you feel
that this idea is feasible?
5) Does anyone have idea /experience about Ahuja components?
6) Can 2 woofers of 8 each give SPL equivalent to one 15 woofer at same
wattage and sensitivity?
7) Please have a look at the following link. It says that it is a one way XO but looking at the picture (by clicking on the larger view option), I felt that it is a 2 way XO with cut off at 4 KHz. If it looks confusing; I will go with the Dayton crossover.
Ahuja Sound Solutions
8) For low pass filter, I will have to use Ahuja only because parts express/madisound do not have low pass filter at 250 Hz (this is very important as this freq is decided by my baffle size.)
Ahuja Sound Solutions
Regards
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Please solve my queries.
