The magnificent Zenith 49cz852's

[markodimarko]

The big Goldwoods seem to be a popular choice for OB woofers. They may still be on sale at Parts Express at 20% off.

The 15" Alpha H-frames take up a lot of floor space and the 18" Goldwoods will require even larger H-frames. OB bass is not about plumbing the depths it's about accuracy.

 

[markodimarko]

Ok I understand your point but I see that you use an extra sub in the corner of your room to boost lower bass.

 

[markodimarko]

The big Goldwoods seem to be a popular choice for OB woofers. They may still be on sale at Parts Express at 20% off.

The 15" Alpha H-frames take up a lot of floor space and the 18" Goldwoods will require even larger H-frames. OB bass is not about plumbing the depths it's about accuracy.

Poultrygeist I understand your point but I see you use a separate cylinder sub at your room...?

 

[Poultrygeist]

Poultrygeist I understand your point but I see you use a separate cylinder sub at your room...?

I've used the bucket subs with the Alphas but they really aren't needed. Maybe if I listened to nothing but E. Power Biggs or electronic music they would be but the great majority of recorded music doesn't go below 40hz. My bucket subs are in storage but I do want to try them with the HT.

 

[opnly bafld]

Thanks Poultrygeist,

I actually will work your way. I plan to play the Zenith without crossover with my 50 se amp and biam the Eminence 15A with a 47labs gaincard with an active crossover. My preamp will output with a y adaptor two outs to the two amplifiers.

However at what frequency do the sub starts to play? Is it above 100Hz or below..?

Thanks

You really need to experiment since you have an adjustable crossover.
Play some test tones to find where the Zeniths start to lose output and play the woofers up to them.
Over time you can fine tune it with small adjustments.

 

[Poultrygeist]

Thanks Poultrygeist,

I actually will work your way. I plan to play the Zenith without crossover with my 50 se amp and biam the Eminence 15A with a 47labs gaincard with an active crossover. My preamp will output with a y adaptor two outs to the two amplifiers.

However at what frequency do the sub starts to play? Is it above 100Hz or below..?

Thanks

These are the 8 inch Zenith alnico's on a flat baffle over double Alphas and since there's no room in the house for anymore large OB's they reside in the garage.

I use a Ashly active crossover for the HF and LF because they are powered by class D amps and the combination sounds excellent. If I were using a SET amp for the HF I would allow the Zeniths to run full range and only filter the LF. If you have a active crossover and a single ended tube amp try it both ways and you'll see what I'm talking about.

My experience is that an active in the signal path sucks some of the life out of the SET amp and if you read the OB Epiphany thread you'll see I'm not alone in this belief. Folks using a flea watt tube amp and mini-DSP to change the frequency report the same issue.

One thing I've learned over the years is to trust experience over opinions.

 

[Poultrygeist]

You really need to experiment since you have an adjustable crossover.
Play some test tones to find where the Zeniths start to lose output and play the woofers up to them.
Over time you can fine tune it with small adjustments.

The problem here is that in stitching two dissimilar drivers together you can miss much of what the Zenith 49CZ*** is capable of. I don't think you have a pair or you would know how spacious they sound as single drivers without helper woofers. In the original Zenith consoles they were used as woofers so it's no wonder they make decent bass on their own. I hesitate to recommend cut off as it's a matter of personal taste. The Alphas or Goldwoods should not be brought in very high or they will mask some of the best characteristics of the Zenith. I would rather use OB woofers to augment rather than try and make an impossible seamless hand off to the full range driver. It's why H-frames are often called subs not because they play that low but because they are used like subs.

 

[opnly bafld]

The problem here is that in stitching two dissimilar drivers together you can miss much of what the Zenith 49CZ*** is capable of. I don't think you have a pair or you would know how spacious they sound as single drivers without helper woofers. In the original Zenith consoles they were used as woofers so it's no wonder they make decent bass on their own. I hesitate to recommend cut off as it's a matter of personal taste. The Alphas or Goldwoods should not be brought in very high or they will mask some of the best characteristics of the Zenith. I would rather use OB woofers to augment rather than try and make an impossible seamless hand off to the full range driver. It's why H-frames are often called subs not because they play that low but because they are used like subs.

I really have no idea what you are talking about, but Eminence calls the 15a a woofer and I used to have a pair of Zenith 49cz....

 

[Poultrygeist]

I really have no idea what you are talking about, but Eminence calls the 15a a woofer and I used to have a pair of Zenith 49cz....

Based on your posts you don't agree with my advice and explanation regarding running the Zeniths full range. How bout posting some pictures of how you used the Zeniths in OB's. And why on earth would you get rid of such great speakers?

 

[opnly bafld]

Based on your posts you don't agree with my advice and explanation regarding running the Zeniths full range. How bout posting some pictures of how you used the Zeniths in OB's. And why on earth would you get rid of such great speakers?

I never said anything about not running the Zeniths fullrange, where do you get that?

 

[markodimarko]

Hi Poultrygeist..
Thanks for the advice.. I am now building the boxes. I want to ask about the tweeter.. I bought the Eminemce asd1001 but I see you pit a realistic super tweeter firing back. Are you trying to have a dipole sound?
Some diy ob speaker guys like Lampizator and Gr research propose to recess by some like 12mm the tweeter compared to the FR in order to correct the phase.
Do you have anything to suggest?
Secondly , do you think that it is important to create a dipole tweeter sound with a back firing tweeter like yours in this ob design?

Thanks

 

[Poultrygeist]

Hi Poultrygeist..
Thanks for the advice.. I am now building the boxes. I want to ask about the tweeter.. I bought the Eminemce asd1001 but I see you pit a realistic super tweeter firing back. Are you trying to have a dipole sound?
Some diy ob speaker guys like Lampizator and Gr research propose to recess by some like 12mm the tweeter compared to the FR in order to correct the phase.
Do you have anything to suggest?
Secondly , do you think that it is important to create a dipole tweeter sound with a back firing tweeter like yours in this ob design?

Thanks

I added the rear firing super tweeter as I felt the ASD1001 was a little too pronounced by itself. Perhaps I didn't pad it down enough but it's probably a matter of taste. This build uses just the front firing ASD1001 and its where I got my inspiration. The Beta 12LTA is used here and its efficiency is very close to the Zenith. So much of this is just experimentation and what sounds best to each individual. That's what makes it so much fun.

https://speakerprojects.wordpress.com/2016/08/29/eminence-beta-12lta-on-open-baffle/

 

[fjdds]

Hello all,

Currently building an open baffle for the Zenith 852's. (pictures to follow)

Couple if quick questions if you guys don't mind. (Or should I start a new thread)


1. What actual diameter should I cut into the baffle? 12 inches? What about if I want to recess using a router?

2. I have a couple of Fostex FT-17H horn tweeters that I bought for another project that I ended up not using. Would these be a good match with the Zenith?
If so, what size cap would you recommend? (I'll put an l-pad for the tweeter to pad it down, if necessary)

I will be using these with a Dynaco Pas-2 and a Magnavox console pull, currently being restored.

Thank you!

 

[Poultrygeist]

1. I mounted my Zeniths in the same baffles that once contained the Eminence Beta 12LTA - 10.95 inches. You might go slightly less but no more than 10.95. A plunge router and Jasper circle jig is the best tool for cutting baffle holes.

2. Decent sensitivity match. Cap size would be trial and error. Maybe 1.0 uF or 1.5 uF? An L-pad is a good idea.

 

[fjdds]

Great. Thank you very much.

 

[fjdds]

Here's the work in progress OBs for the Zeniths . Ok. not exactly woodworking expert structures, but they should serve, once I get them stained and tung'ed.
Anxious to put them together and give them a listen.

 

[Poultrygeist]

This is what I use to cut holes for the drivers. You can do it with a jig saw but the results won't be as good. The Zeniths are so light weight they were originally mounted to the rear of the baffle cut outs. That's the way they came in the old consoles. The Zeniths have ugly beige gaskets which scream paint me black and I did.

 

[Poultrygeist]

Here's the work in progress OBs for the Zeniths . Ok. not exactly woodworking expert structures, but they should serve, once I get them stained and tung'ed.
Anxious to put them together and give them a listen.

Very nice. Glad you left room for woofers.

 

[fjdds]

That's the plan. Thought I would place the Zenith's only for awhile, and determine whether or not to add the other drivers.
(Router and circle jig on order!)

 

[Poultrygeist]

That's the plan. Thought I would place the Zenith's only for awhile, and determine whether or not to add the other drivers.
(Router and circle jig on order!)

That's a good plan. Listen and decide.